Comprehensive Guide To Central Heating In The UK

How Does A Gas Boiler System Work?

The boiler is the foundation of the central heating system. It sends heated water through to the taps and radiators to provide the home with hot water and heat. 

Gas boilers are either connected to gas mains where the supply of fuel is constant or run on LPG (Liquid Petroleum Gas) cylinders requiring periodic refilling. When the boiler is in operation, the valve that connects the boiler will open allowing gas to flow inside the sealed combustion chamber. A permanent pilot or electric-ignition system will then ignite to burn the fuel. 

Hot jets connected to the heat exchanger inside the boiler then transfer heat to the water, flowing over the exchanger. The electric pump will then push the heated water through to the taps and the radiators. 

All modern boilers are now condensing. They come with built-in heat exchangers that extract heat from flue gases. The condensing boiler then recycles the latent heat produced by water vapours which is a by-product produced through this heating processes. This heat is used for heating the water which returns from the central heating system. This type of system reduces energy waste since the heat energy required is reduced. By law, all the latest boilers have to be condensing. 


Boiler Types And How They Work

Even though the standard process of burning fuel and then sending the heated water to taps and radiators generally works the same for most boiler types, each type works differently.

Here is an overview of each boiler type, how they work, and how they provide hot water and heat. 


  1. Combi Boilers

Combi boilers provide hot water and heating to homes without the need for additional cylinders or tanks. They feature two heat exchangers with one connecting to the radiators and the other linking to the hot-water supply. 

Since there are no cylinders or tanks required, the combi boiler is always on standby, meaning it provides on-demand hot water. When heating or hot water is needed, the boiler burns fuel, causing the heat exchanger to heat the water. 

The combi boiler system also features control valves that operate in more than one direction, depending on whether heating or hot water is required. 


  1. Conventional Or Heat-Only Boilers


The heat-only boiler is a more traditional home heating type. These systems operate with an additional hot water cylinder (for water storage) and a cold water tank. These boilers also come with a built-in expansion and feed tank, that brings in the cold water for regulating water levels. This tank assists with expansion as the water heats up, and it also replaces water that is lost through leaking or evaporation. 

The mains supply fills up the cold water tank with water. Once in operation, the boiler sends heated water to the radiators or the hot-water cylinder. Provided the hot-water cylinder has enough water inside, it should be possible to access the hot water from more than one tap at a time. 

These conventional boilers can also come fitted with backup immersion heaters, which will provide access to heated water in cases the boiler breaks down. 


  1. System Boilers


A system boiler provides hot water and heating with the use of an extra hot water cylinder. The majority of the heating components are built into the system, so they do not require additional storage tanks. They work in a similar way to the heat-only boiler, but they require fewer additional components. 

The system boiler is a sealed pressurised system. A filling mechanism is used to source cold water from the home's mains supply. The water then heats up where it is stored in the hot water cylinder or onto the radiators. When hot water is required, these systems then send the heated water to the taps. 

Types of Central Heating Systems

 If you are looking to update or replace the central heating system in your home, here is a comprehensive guide on how to choose the right heating system to suit your home. 

There are many factors to consider before deciding on the ideal option to keep your home warm. 

There are various options to choose from. However, before you proceed further, It would make sense to clarify what type of central heating system you are currently using. 

The costs involved in fitting and supplying a boiler typically vary according to the size, brand, and installation cost. The cost to install a boiler will increase significantly should you decide on a completely different system from the current system. Depending on the current state of your heating system, this may or may not be a cost-effective option to choose.

It's also worthwhile noting that the prices vary considerably from one installer to the next. For this reason, we suggest that you compare 3 to 4 quotes to ensure you are choosing a service that is competitively priced. 


Electric Vs. Gas Systems

Central heating systems are usually not front of mind. and are often taken for granted by many homeowners until something goes wrong. But what system is more reliable? A gas or electric heating system? Which type is more cost-effective to run?

In the next section, we have covered these questions. We hope this will give you the information you need to make the right choice between a gas or electric system.


How Do Gas Heating Systems Work?

In the UK, the gas heating system is the most common. This type of heating system also called a  "wet system" consists of a gas-fired boiler that heats the water. These heating systems provide heating through radiators and the hot water to the taps in a home. Here is a step-by-step description of how they work:

Step one: Natural gas supplies the boiler from a pipe that is connected to the gas main out on the street. 

Step Two: The gas jets are aimed at the pipes that contain cold water, heating the pipe to around 60 degrees Celsius. 

Step Three: Water pipes make up only one section of a larger circuit of continuous pipe. This is a network that travels around your entire home. 

Step Four: The water passes through the radiators, before returning to the boiler. 

Step Five: As water flows through each radiator, it releases some heat which warms up each of the rooms in your home. The boiler must keep firing to make sure the water remains at a temperature high enough to keep your home warm. 

Step Six: These systems also use electric pumps to direct the flow of water around the central heating circuit and the radiators. 

Step Seven: Houses that are not connected to a gas network still use LPG (liquid petroleum gas) or a type of heating oil that works like gas but is more costly to operate. 


The Running Costs Of Gas

Gas boilers often offer significant savings. Some estimates have suggested a saving of up to £250 per year in comparison to other fuel types such as LPG, coal, or oil. 

Condensing, high-efficiency gas boilers might convert up to 90% of fuel consumption into useable and useful heat. The condensing gas-boilers are also known for producing a lot less CO2 or carbon dioxide when compared to standard gas boilers. They also lower heat loss from a flue. 


How Do Electric Central Heating Systems Work?

Electric boilers can be used as a replacement for a small or a medium-sized gas boiler, and as technology continues to advance, there are now electric boilers that match up to the requirements of larger homes.

These boilers also require fewer components when compared to gas boilers which makes them lighter, smaller, and more compact. They also run silently and offer an important advantage of being completely efficient. Electric boilers are still regarded as the new-comer to central-heating markets, and they are more commonly found in rural sectors when gas or oil supplies are not readily available. However, today they are also common in flats and newer housing projects that install electric boilers due to their environmental benefits

If you are thinking about changing over from a gas boiler to an electric boiler, it is important to know that the costs involved are significant, once factoring in the boiler, new piping, and the cost of installation. 


Is It Cheaper To Heat A Home With Electric Or Gas?

Gas-powered central heating systems are usually cheaper over the long term. 

Even with a slight shortfall in energy efficiency, the electric boilers at this stage, cannot compete with the 4p / kWh costs of gas. 

If you are not sure about which central heating system to choose for your property, we suggest contacting an engineer

The Most Popular Central Heating Systems

Today there are many central heating systems to choose from, which fall into different categories, these include:


1 Combi-Boiler System 

Combination boiler central heating systems are perhaps the most popular system today. This system does not need a hot-water cylinder, expansion tank, or feed tank since they heat water on demand. This also means these systems are more economical and require less space since they are only heating water when you need it. 

The combi-boiler system provides on-demand heated water, which means you won't have to worry about a tank taking up space in your loft. 



- Electronic controls pair to the boiler

- The main supply is directly fed to the combination system

- The thermostatically-controlled modern radiators are sized accordingly

- Space-saving

- Performs very well in a shower

- Hot water as you need it (on-demand)

- Economical since you are only heating the water that you use

- Eliminates the risk of frozen pipework

- Installation is typically cheaper


Combi-boiler systems also come with a few drawbacks. The main concern is the flow rate is relatively low since the water must heat up while travelling through your boiler (there isn't any stored hot water to rely on).

This also means that this system is not suitable for houses with 2 or more bathrooms since using water in 2 bathrooms at the same time will translate into an even slower flow rate.

Combination boilers have 2 heat outputs:

- Hot water for showers and taps

- Hot water for radiators and the central heating system

It requires more heat and effort to provide hot water to a shower or tap than it will to a radiator. For this reason, it is important to consider what type of hot-water output your home will need. 


2 Mains Pressure Heating Systems

This is a system that supplies mains-pressure heated water through taps in a home. 

The water is extracted from the cold-water mains and is then heated by the boiler. 

The water is stored inside a storage tank also known as the "unvented cylinder" until it is needed. 

When you open one of the taps in your home, cold water that comes from the mains forces hot water into your central heating system which then flows out of the tap. 

The pressure at the taps in a high-pressure heating system will be the same pressure as your mains which is usually much higher than what you normally experience. 

This type of central heating system is ideal if you already have a high-mains pressure, but if you have a low mains pressure this is not a suitable system. They are also expensive to install with some authorities requiring a certificate for annual maintenance that you will have to submit to them. 

It is also important to make sure your flow rate and mains pressure will be strong enough that they can power the central mains-driven heating system. 

If you have gone through the hassle and expense of installing this heating system and the water is only trickling out of your shower or tap, at this stage, there is not much that can be done to rectify the problem. 


Conventional / Regular Boilers

These types of central-heating systems use a system or regular boiler to heat your hot water and the radiators. The heated water will circulate around this system before it is stored inside the hot-water cylinder until you need it. 

Water that enters the boiler before it is heated usually comes from either an expansion tank or feed tank located in your loft space. It will also ensure that the water volume inside the system is constantly kept at an optimum level. 

There is also usually, a bigger tank that will replenish the hot-water cylinder after using water around your home. 

Water from the tank draws into this system by gravity, which is where this heating system derived its name from. The main disadvantage to these systems is that they require loft space to accommodate the 2 tanks, along with an airing cupboard or something similar to accommodate the hot-water cylinder. 

The gravity-based heating system works well if you have low mains pressure in your area, since the force of gravity associated with these systems usually provides more water pressure, especially when your main pressure is not doing the job. 


Wall-Mounted Boilers

Many of the latest models of boilers are designed to be wall-mounted along with lighter and compact heat exchangers made from materials such as aluminium, copper, stainless steel, or cast iron. 

Wall-mounted boilers are available in various versions which include Room Sealed or Fanned Flue. Similar to many other models of new boilers, these wall-mounted types must have a "system-by-pass" fitted to filter the water through the boiler to stop loud noises that boilers make known as "kettling". 


Free-Standing Boilers

Usually made narrow enough so that they fit between kitchen units. Since they are free-standing, you can also install them in other suitable locations. These boilers were once popular in the 70s and the 80s, and they are still a good option if you do not have enough wall space available for one of the wall-mounted boilers. 


Condensing Boilers

This boiler type offers a highly effective "heat exchanger" that allows the heat to re-circulate instead of losing this heat in the flue, which makes it a lot more energy-efficient. This can help to reduce your fuel costs significantly. 

One often mentioned issue about condensing boilers is the "pluming effect" that they create inside the flue terminal (it is often mistaken for steam). Plumeing is caused by water droplets that are suspended throughout the flue of the boiler. It is not dangerous in any way but can be regarded as a nuisance that occurs consistently while the boiler runs. Due to this problem, the position or placement of your condensing boiler could be an issue.


Common Types Of Boilers Faults

photo of a boiler on a wall

To get the most out of a boiler it is advisable to fire it up every so often during the summer. This will lower the chances of the system breaking down when turned on in the winter. But, there is usually not much to be concerned about, if an issue does come up. Fortunately, many central heating system problems require a simple fix, when something more serious arises, it is best to contact a heating engineer or plumbing mechanic to provide the most effective solution to the problem. 


Here is a list of some of the most common problems that homeowners experience with central heating systems:


- The Thermostat Controls Stop Working

In some cases, the homeowner has forgotten to switch on their thermostat. The temperature should always be set between 17 to 20 degrees centigrade as this is recommended as a good temperature range. If the radiator fails to heat up, the next step is to check the programmers to make sure the HW (hot water) and CH (central heating) setting is on. 

From here, the next step involves checking whether electricity is being supplied to the system. This also includes checking on the fuse as it might have blown. If this is not the problem, there might be an issue with the motorised diverter valve. This part controls hot water flow. Turning it off and then turning it back on again may solve this issue. 

Finally, if this does not solve the issue, the pump may have broken down. This is the device that pumps heated water from a flow pipe into the radiators and the taps. Mechanical failure and blockage are two of the most common problems with this part. If the pump is clogged it will require an intensive clean to get rid of the dirt that has accumulated inside or may need to be replaced. Trapped air can also cause the pump to stop working. There is a very small nut that will help to release any excess air. As soon as any water starts to flow out while releasing the trapped air, the nut can then be closed again. From here, the pump can be tested again to determine whether it is working. 


- The Radiator Only Warms Up At The Bottom

This issue is actually common and is easy to fix. The solution involves bleeding the radiator. The pump needs to be switched off to stop air from getting inside the system. place a bucket under the radiator. On one side of the radiator on the top is a brass square nut that can be opened with a radiator key by turning the nut in an anti-clockwise direction. This will allow any air inside the radiator to escape. As this happens, any dirty water will flow into the bucket. These radiator keys are easy to find in most hardware stores. This tool is essential for bleeding a radiator. After bleeding the radiator, the valve must be closed properly to check that there are no leaks. 


- Sludge In The Heating System


This commonly occurs due to a build-up of debris inside the radiator. This build-up must be flushed out, by taking the radiator off the wall and then flushing it out with fast running water. If this step does not solve the issue, the pump may be broken, a pipe might be blocked, or the heating system is poorly designed. 


- Strange Noises Coming From The Heating System


Kettling is the common name used for a sound that a boiler makes. If the boiler starts making this noise the first time that the pilot light is ignited, it may be caused by trapped air. The excess air can be vented out of the air-bleed screw. If this fails to solve the problem, check whether enough water is reaching the boiler tank. These problems can also come about due to a build-up of sludge. Flushing the system is the best way to solve this problem. If the system is pressurised, make sure the setting is at the correct level. 

- The Overflow Doesn't Stop


With a system or traditional boiler, the water tank situated in the loft will feed water to the heating system. If the ball-cock is jammed, it will create an overflow problem. When it comes to immersion tanks, only an expert plumber should be handling these issues. 


- The Heating System Pressure Drops Dramatically


There are many reasons why this problem occurs from excess air inside the system after bleeding out the radiator to water leakages. After a maintenance service, the system needs to be topped up with water, if there is a noticeable pressure drop. Expert engineers who have extensive experience installing central heating systems in London suggest using the filling loop to add more water. if you are unsure about how to do this, it is always better to hire a professional gas safe engineer to handle it for you. 

When central heating systems break down due to a boiler defect, it can become very costly. Losing hot water during the winter months is definitely not a pleasant experience. If you are faced with a problem, contact our Emergency plumbing services, solve your problem as fast as possible. 

Central heating is one of the essential parts of any home to keep the home comfortable and warm, especially during the coldest months of winter. Here is more information explaining what costs are involved in install new central heating and boiler systems in your home. 

What Are The Costs Involved To Install Central Heating?



Many UK homes still use old-fashioned and outdated central heating systems. These include electric heaters or gas fires. While the upfront costs involved to install a new central heating system and boiler can be costly, money can be saved over the long term, since modern home heating systems are far more energy-efficient, which translates into a reduction in energy bills.

The overall costs of central heating systems vary and mainly depend on the size of the home and the installation process. In general, the costs to install a new boiler includes the boiler itself, along with the pipework and any other parts required, as well as the labour that a Gas Safe registered engineer provides. 

Boiler Prices

The size of a home along with the bathrooms and radiators are taken into consideration to decide on a boiler type that is going to provide the home with enough hot water and heat in the most efficient way. 

The three most common boilers types include the system boiler, the heat-only boiler, and combi boilers. If the home already has a system or conventional boiler installed, the quote will include an extra cost to install a cold-water storage tank and/or hot-water cylinder. 

Since no tank or cylinder is required for combi boilers to operate, this can be a more cost-effective option. However, if a system or conventional boiler is converted to a combination boiler, there is usually an additional cost added to remove the cylinder and/or water tank. 

In general, when a large kW output is required for a new boiler, it typically costs more than those with a lower kW output. 


Additional Requirements And Parts

The boiler is only one part of a central heating system. Other elements are also needed to keep the home warm. When additional parts are required, this can increase the overall cost of the installation. Here are some examples of additional parts that increase the cost of the installation:


- New radiators, when the existing radiators are inefficient and old, blocked by debris, or faulty.


- When a power flush is required to remove debris and sludge from the current system.


- When filters are fitted to improve efficiency and extend the lifespan of the boiler.


- The choice between installing smart-heating or traditional controls with the new boiler.


- Pipework might need to be added, rerouted, or replaced, which will depend on the current condition of the pipework, or when the boiler is relocated to somewhere else in the house. 


The list above is just a few common examples of what may increase the overall costs for a new boiler installation. 



When working with gas appliances it is essential to ensure that the engineer is Gas Safe Registered, since only Gas Safe Registered engineers can legally work on gas-powered appliances. Here at Heat Quick Direct, our engineers are all professionally trained and Gas Safe Registered to ensure you receive a professional and high-quality installation. The complexity and time it takes to install the system are also factored into quotations. 

The costs involved to replace a boiler often vary, but they most frequently rely on factors such as the size and model of the boiler, and the complexity involved to install the system. 

When it comes to replacing boilers, it is important to keep in mind that the cheaper options may not be the best choice over the long run. It is better about it as an investment that will improve the quality of the home's heating. Even though modern boilers are more expensive when compared to traditional options, they often include innovative features and designs that heat homes a lot more efficiently. Ultimately, this helps homeowners to save a lot of money over the long term. 

The price to replace a boiler also has to do with the brand that is chosen. For example, a manufacturer like Worcester Bosch is regarded as a premium brand when compared to others. At the same time, it is essential to make sure that the Gas Safe Registered engineer has the knowledge and skills to successfully carry out an installation professionally and safely. 

The boiler cost on its own is usually lower when compared to the final price to replace the unit since labour costs still need to be factored in. When the installation involves additional work such as pipework modifications or scaffolding it can add to the overall costs. The costs can also increase when changing over to another system. Examples of this include changing from a standard gravity-fed boiler to one of the combi boilers. 


How Are Boiler Sizes Measured?

Boiler sizes are measured in kW (kilowatts). Kilowatts are the units that define the amount of energy that the boiler will output (in the form of heat). 

In general, homes that require a lot of hot water and heat will need a higher kW boiler, when compared to homes that require only a moderate amount of hot water and heat. 


Is It Wise To Oversize A Boiler?

In previous years when the insulation in homes was extremely inefficient where a lot of the heat from the boiler was lost, and the energy efficiency of these boilers were of 70% or less, some engineers used to advise that oversizing the kW of a boiler was a good idea to compensate for the heat that was lost. 

Today, most of the A-rated boilers operate on 90% or more energy efficiency, and most homes feature efficient insulation, which means it is no longer necessary to oversize a boiler. 

However, it may still be a worthwhile option to oversize a boiler when an extension is added onto the home or adding more radiators or another shower onto the property, or when a bedroom is converted into an en-suite. It means anything that is going to increase the heating demands or hot water from the boiler. But in most cases, it would be a waste to oversize a boiler since they use too much energy, cost more, and are generally bad for the environment. 


What Is The Right-Sizing For Hot Water?

Another consideration for the kW output for a boiler has to do with how much hot water output is required. The flow rate for hot water on a combination boiler is LPM, which stands for "litres per minute". This is an indication of how fast the boiler can heat the water. LMP varies from 9LPM to 25LPM flow rate. 

Most UK homes have combination boilers installed since they provide convenience since they heat hot water without the need for separate storage tanks in the loft to store hot water. The households that have higher water demands, which means running two or more showers or baths at the same time will usually do better with a system or conventional boiler. These systems include tanks that store hot water so that it is ready when needed. 

The output of a combination boiler increases when the flow rate required to fill baths and heat water more quickly also increases. Conventional and system boilers are a better choice and more efficient when it comes to larger households, but they also cost more to install and will require enough storage space to accommodate the hot-water storage tank. 


The Number Of Radiators

Another factor to consider when choosing the ideal kW boiler has to do with the radiators in the home. When there are many radiators in the home the boiler needs to work harder to keep each one at a desirable temperature.

Small flats with only 3 to 4 radiators only require relatively low kW boilers of around 12 to 24 kW. While the standard 3 to 4 bedroom home with around 10 radiators would typically require one of the medium-sized combi boilers of around 24 to 30kW. With a larger home that features up to 20 radiators, a larger combination boiler is required of around 35 to 42 kW to provide enough heat. However, with homes of these sizes, it would be more practical to choose a conventional or system boiler. 



Insulation also plays an important role when it comes to kW boiler requirements. Poorly insulated properties often experience less than adequate heat retention, which means the boiler has to work much harder to maintain a consistent temperature. 

Improving the loft/cavity insulation or upgrading windows from a single to a double glazed option will improve heat retention. Thermal leak detectors are also available on Amazon at reasonable prices to detect any areas in the house where heat might be escaping. 

The newer builds are generally a lot more efficient when it comes to insulation but by law, the newer homes are required to have a heat pump installed as opposed to the gas boilers. The heat pumps only work with modern insulation which is why they are not suitable for older houses. 


Additional Factors

Other factors also contribute to the kW boiler that is most suitable for a home. Some of these include:


- Fuel Type


At this stage, gas is still the more efficient fuel type for homes in the U.K, but there are also a lot of homes that have left the National Gas Grid, that now use oil or LPG boilers. The less efficient fuel types generally require more powerful kW boilers. 


- Water Pressure


Different areas typically have different types of water-pressure levels, while older properties may have a low water pressure when compared to newer homes. For homes that have lower water pressure, a higher kW boiler that features an adequate flow rate is recommended to avoid pressure drops when more than one tap is used at a time. 


- Alternative Energy


When a boiler connects to, or the homeowner is planning to connect the system to an alternative energy source like solar power, a powerful kW boiler is not necessary, since it won't be working as hard to heat the home. 

Many of the latest boilers feature designs that make them compatible with different alternative energy sources. It is always advisable to first check with the manufacturer whether the boiler will work with an alternative energy source. 


- Maintenance


Similar to other appliances, boilers should be maintained regularly to ensure that they are performing at optimal levels. An annual service for a boiler is important to make sure it runs smoothly, very similar to the way a car requires a service every year. 

We are hoping that our guide has provided you with the information that you need to understand what a boiler suit your home. 


Finding the right plumbing and heating engineer to replace your boiler system


photo of an engineer working on a wall mounted boiler

The decision to buy a new boiler is commonly made in haste. Mostly, you want to get your central heating back to its normal working condition and get hot water flowing as fast as possible after your boiler stops working in the middle of the cold winter season. However, the process of choosing a new boiler and installer can be quite challenging. More importantly, you might end up paying an arm and a leg if you choose an unreliable boiler or installer.   

 To help you understand the proper process of choosing the right boiler and installer, we have compiled a comprehensive step-by-step guide from experts in the industry. Tips on how to extend the life of your boiler are also included in this list. To learn what you need to find out from your boiler technician (from what to look for in a trustworthy boiler installation engineer to how to inspect a quote to ensure that it represents value for your money) when they come in for an in-person visit and give you a cost estimate, read on below. Read our detailed boiler guide to learn more about the best option, suited to your specific needs.    


Boiler Installation Cost  

 Your boiler engineer should take their time when putting together a cost estimate for the installation of your new boiler. Before recommending a suitable boiler type and size, the right installer should carefully assess your home’s hot water and heating needs by conducting a comprehensive survey. As such, before talking with an installer, be sure to consider the following factors.   


For The Best Outcome Answer The Following Questions 

In addition to informing your installer about any plans, you might have for your home in the future, make sure that you layout your hot water requirements comprehensively. Take some time to ponder the following questions and use the answers to brief the boiler installer: 


  • How many outlets do you normally draw hot water from regularly?


This question tries to ascertain how hot water is used in your household on a regular basis. 


  • Would you like to have a shower that requires pumped power in the near future, or are you already using one? 


A powerful electric pump cannot be paired with a combi-boiler – which means that you cannot enjoy the boiler’s space-saving benefits. As such, you will be forced to sacrifice your shower’s pump if you choose to go with a combi-boiler.  


  • Do you normally experience any fluctuation in your home’s hot water needs throughout the year?


If you normally have guests staying over during the holidays, or any other time in the year, your hot water needs are likely to fluctuate. 


  • Are you planning to conduct any related home remodeling projects in the near future? 


It is important to inform the installer of any future plans to install under-floor heating, extra bathroom, extension, solar panels, or loft conversion. 


  • Has the heating system in your home been experiencing any issues? 


Inform the boiler technician about any, and all, of the problems that your existing heating system has been experiencing.  


  • Do you have a preferred brand of boilers in mind? 


The best boilers are most likely bound to be three times more reliable than the worst ones in the first 6 years, as reliability is quite varied among different brands. Regardless of what your installer says, you should only choose from our recommended list of highly-rated brands. Always remember to choose a brand that suits your needs, instead of what the installer says, especially because some installers are paid (or rewarded) to recommend some brands.     

 Unlike the best ones, the worst brands are three times more likely to experience problems. 

 To ensure that the installer can recommend a boiler that is suitable for your home, it is paramount that you comprehensively answer the above questions.  

 For the best installation, don’t forget to ask about the following. 

 A good installer should be able to point out the following about your hot water requirements to ensure that you make an informed final decision. Be sure to ask about the following if the installer fails to mention any or all of them. The right installer should be able to explain all of the following extras, pointing out which is necessary.    

 In most cases, some of the extras mentioned below will not be required. The benefit of getting each service should be compared to the cost – which varies from property to property.   


Condensate Disposal 

 The condensate – water produced from the boiler – is directed to the drain through a network of pipes. The need for external piping should be minimized. The installation expert must ensure that any external piping, if necessary, is installed per instructions from the manufacturer, and shielded from cold weather.  

 Boiler Water Treatment 

Assuming that you live in a 3-bed semi-detached home with ten radiators, you can expect to pay around 375 pounds for water treatment – i.e. flushing and cleansing. A straightforward gravity cleanse and flush – with a chemical inhibitor at the system’s final fill – is the minimum requirement for most heating systems. On the other hand, a power flush might be necessary for systems that have a lot of sludge. The best fit, as well as the reasons behind that choice, should be pointed about by your installer. Here are some of the signs of a system that has a lot of sludge:    


The heating system is noisy during operation


The system takes longer to heat-up


The radiator has cold spots. 


Using a tissue to carefully draw a small volume of water from the radiator valve, you can get an idea of just how dirty or clean it is on your own. To prevent the accumulation of scale, corrosion and sludge, remember to ask the installer to add a chemical inhibitor when refilling your heating system.  


Scale Reducers/System Filters


Since scale reducers and system filters can extend the life of a boiler, find out from the installer if they are necessary for your new system. The cost of buying and installing them should be about 120 pounds. Combi-boilers installed in an area with hard water normally require scale reducers. Before the process of installing a new boiler starts, you must consider the need for a system filter or the previously described power flush, even though it may not be necessary for all situations. Sooner or later, you are bound to encounter various reliability issues if your new boiler is installed on an incompatible or dirty heating system.

If you are looking for a professional boiler Installation check us out at Heat Quick Direct London


Get a Gas Safe registered engineers.

Engineers that are not Gas Safe Registered may be putting countless homes at risk each year due to the dangers of carbon-monoxide poisoning and many other hazards. 

Whether a faulty gas-powered gas appliance needs repair in your home or a landlord interested in installing a new boiler before your next set of tenants take up residence, it is vital to ensure that you only hire an engineer that is Gas Safe Registered. These are the only professionals that have the experience, equipment, tools, and experience required to carry out these jobs to a high standard. 

So what does Gas Safe Registered mean? And how can one tell whether the engineer has these accreditations?


- Background Information


Any engineer on the Gas Safe Register has received the qualifications and correct training to perform work on and install gas appliances. These include fireplaces, cookers, and boilers. The HSE (Health and Safety Executive) has official lists that contain over 120,000 businesses in Guernsey, Isle of Man, and the UK that are Gas Safe Registered, along with more than 70,000 engineers. 

It is important to know that it is unlawful to work on any type of gas appliance when the person is not Gas Safe registered. 

The Gas Safe Register is in place to ensure that these businesses and engineers maintain a high standard when it comes to the work expected of these businesses and people. It is also in place to gather information against organisations or individuals that have performed sub-par or poor work to pass onto the HSE. 


What Are The Benefits Of Using A Gas Safe Registered Engineer?

It may seem like a good idea to try and fix a boiler on your own or ask someone that is not Gas Safe Registered to look at your boiler when you are trying to save money. But it is important to know that you are taking a gamble and here is why. Engineers that are not Gas Safe Registered are not trained properly on how to perform safe and professional work when it comes to gas appliances. For example, when installing a new boiler, carbon monoxide leaks can become problematic when there is not enough ventilation. Gas Safe registered engineers know what to look for along with any other potential issues. 

From explosions to fires, gas appliances that are not installed or repaired properly can pose many risks, which include carbon monoxide leaks and poisoning. Carbon monoxide is a dangerous odourless, and colourless gas that can leak from an appliance posing a danger to the lives of all the occupants in a household that are breathing it in. 

With a Gas Safe Registered engineer it provides the homeowner with peace-of-mind and assurance that the work is carried out professionally and by a person that knows what they are doing. It is important to know that your tenants, your family, and yourself are safe when it comes to gas appliances in your home. 


- How To Spot A Genuine Article


Getting onto the Gas Safe Register is not an easy task. Engineers are required to undergo various stringent checks. For this reason, you can be sure that all the Gas Safe registered engineers will be reliable, experienced, trustworthy, and professional. 

But just because someone is saying that they are Gas Safe Registered, doesn't always mean that they actually are. For this reason, it is essential to ask the engineer for proof before they start working on your appliances. You can also refer to the list on the official website of the Gas Safe Register. 

Look for engineers or companies that display a yellow triangle, as this is the symbol that the Gas Safe Register uses. You should also ask the engineer for their ID card, which will provide all their professional details, from the work they are able to carry out to their qualifications. 

This card should contain an ID number that should appear on the Gas Safe Register list. You should also check whether the date on the card is up-to-date (engineers are required to register annually). The professionals that hold the right accreditations will have no problem displaying their ID card. 


Tips On How To Calculate Radiator Size

When adding or replacing radiators in a home, every room in the home must be getting the correct size radiator. If the radiator does not produce enough power it won't warm up the room, and if the radiator is too large it will make the room too hot, and end up costing more money to operate. The power or size of a radiator is measured in something known as BTUs. 


What Is BTU?


BTU is the abbreviation for British Thermal Unit, which indicates the amount of heat that the radiator can give out.  One BTU is also an indication of the energy required to heat 1 pint of water by a degree (Fahrenheit). When the BTU number increases the faster the radiator is able to warm the spaces around it. The sizes for the central-heating radiators typically have BTU output between 600 to 10,000, or sometimes even higher. 


To make sure you are investing in the right radiators for a home, here are a few important considerations to keep in mind:


- The size of the room. This involves knowing the exact dimensions of a room where a radiator is required. This information is represented in square-metres. 


- How many windows does the room have? Every window can represent potential draughts, so this should also be factored into the calculation. 


- How many radiators do you need? Particularly large rooms will not receive adequate heating from one big radiator. 2 or 3 smaller radiators will usually deliver improved and more consistent comfort levels. 


- What is below, above, or on the opposite side of a wall? Radiators against or on a solid wall or floor or under a well-insulated ceiling are not forced to work so hard when compared to the radiators placed against a cavity wall or above a cellar. 


This information should help you to determine how many and the size of the radiators that your house needs. Based on average room sizes in the U.K. here is a list of a few estimates to provide you with the starting point that you need for your research. 


What Are The Costs Involved To Replace A Radiator?


The like-for-like radiator replacements where you are replacing your radiators with the exact same size and type of radiators you plan to remove is the easiest task for heating engineers, which means it is also the lowest of the cost options. 


Labour costs will also vary according to your location. For example, replacing a radiator in a home in London is going to cost more than the homes in the northern UK. The costs also vary according to the engineer chosen, the complexity or simplicity of the job. On average, radiator replacements range between £100 – £300, which includes labour costs.


A like-for-like replacement: £100 – £200

Installing additional radiators: £150 – £300

Relocating existing radiators: £100 – £150


The quote usually includes the cost of a radiator and any TRVs (Thermostatic Radiator Valves) and additional pipework, and any labour involved such as removing and draining old radiators, mounting, bleeding, and filling a new radiator, opening valves, installing new pipework, etc. 


The ideal way to know you are paying a fair price for radiators is to ask for quotes from at least 3 to 4 companies so that you can compare the costs involved. For instance, independent engineers might provide you with a cheaper price when the turnover of the business is under the VAT threshold since they are not required legally to pay VAT.


If you plan to add one or more radiators to your house, you need to ensure that the boiler can easily cope with this additional heating demand. If you only plan to add 1 or 2, your existing boiler will most likely be fine. But when you are not sure or you plan to add 3 or more, it is best to ask an expert engineer to examine your existing heating system. 


What Is The Best Type Of Radiator?


Plumbed Or Electric?


Radiators are either plumber to a central-heating system or they are electrically powered. 


An electric radiator is individually controlled and simply needs the mains-electricity supply in order to work. Some models are basic plugins, but other types will require the services of an electrician.


Plumber radiators connect the hot-water system through the pipework. In most cases, the boilers in homes heat up the water from a mains supply. The hot water will then flow around the radiators and pipes in the home. The plumbed radiators can only be fitted by a heating engineer or a plumber. 


Steel Panel Radiators


A steel panel radiator is a common option since they are cheap and very energy-efficient. They have wavy or corrugated panels, designed to increase the surface area of the radiator which enable the unit to emit or release more heat. Steel panel radiators come in various sizes to match up to just about any room. They also come in triple, double, or single panel models. The models with more panels obviously emit more heat. 


The steel panel radiator models typically come in white, and this is a drawback for some homeowners. For those interested in the efficiency and low costs of the steel panel radiators, but are not sure if these units will match up to the decor in a room, there is the option to buy a cabinet or radiator cover to keep the unit discreetly and safely out of sight. These models come in many colours and styles, and they are simple to install. 


Column Radiators


The column radiators feature vertical pipes that suit period and more traditional homes. They look similar to the original radiators used in the Victorian era, yet they can deliver modern-heating efficiency. The column radiators are available in many sizes, along with 2,3, or 4 columns. The radiators with the most columns are the ones that emit more heat. 


These models do occupy more space when compared to other modern radiators, and they are known for trapping dust and debris between each column. They also require a regular brush to make sure they are running efficiently. 


Designer Radiators


Today it is easy to find an extensive range of plumber and electric designer radiators. These options have become popular with the owners of homes that are looking for ways to not only save space but also to integrate radiators into the decor in their homes. Some homeowners even use their designer radiators as an attractive focal feature. Some of these radiators can also double up as a mirror, magnetic-memo board, or a heated towel rail. In addition to the profiles and sizes available, you can also choose a finish or colour such as chrome, wood veneer, stainless steel, or black. 


Thermostatic Radiator Valves


Any plumbed radiator will require radiator valves that will allow you to control the amount of heat the radiator is emitting. There is a choice between the thermostatic radiator valves that self-regulate or a manual option that involves a few simple taps that you control. TRVs can also detect the room temperature, and when the chosen temperature is reached the TRV will shut the radiator off. This also means that you can choose the temperature for each room in your home. This can help you to save on energy by not heating rooms that are usually empty or where you want the temperature to be a bit cooler. 


The TRVs cost around £5 but can go up to £30 or more when it comes to the smart TRVs that are controlled through an app from a smart device. Here is more information in Radiator Valves Explained. 


Where Should You Place Your Radiators?


It is important to decide where you would like to install your new radiators since this can affect the size and the type that you should be buying. 


Brickwork And Walls


Solid masonry walls, blockwork, or brickwork, can handle most of the radiator types provided they have been attached with the correct fixings. There should be no restrictions where you hang the radiator. Hollow spaces behind the wall or stonework can become a bit more tricky. With these walls, the radiator must attach to these studs vertically or to horizontal timber pieces where the plasterboard attaches. This can restrict the type and size of the radiator you plan to install. 


A radiator should only be installed on a wall that is in optimal condition, which means crumbling plaster or cracks need to be repaired before you install them. 


Existing Plumbing


It is also important to assess the existing pipework in your home. The easiest scenario is when pipework runs along a wall, which allows you to fit radiators that are slightly wider or a similar width with very little pipework cutting. If the radiator is smaller, extra pipework might be required to bridge these gaps. Pipework that runs from a floor upwards can be slightly more complex, especially when changing the style or size of a radiator. This installation may require lifting the floorboards during installation. 


When a wall-hung radiator is not an option or you prefer one of the other alternatives, you might be interested in skirting-board heating or underfloor heating as an easy way to maximise the space in a room. 


Radiator Maintenance


Bleeding Radiators


You should be bleeding your radiators at least once a year to make sure they are working efficiently and that you are keeping your overall energy costs down. As time goes by, air bubbles often accumulate and this means that hot water can no longer fill your radiator, which means the room is not heating up as it once did. You might find that you have to run your boiler for longer to get to the same temperature which translates into increased fuel bills. 


Bleeding a radiator simply involves letting the air escape. You can either do it on your own or hire an engineer to do it for you. The costs involved to bleed a radiator costs between £75 – £150.


Balancing Radiators


Balancing a radiator is also something you or an engineer should be doing once the radiator has been bled. If you find that some radiators in your home take longer to heat up when compared to others, it might mean that you need to adjust the lockshield valve. 


Flushing Radiators


Flushing a radiator is only something a professional engineer should be carrying out since it involves the addition of chemicals to the heating system that flushes out the rust, sludge, and debris that naturally builds up over time. You can also install a magnetic filter to reduce or prevent these build-ups. On occasion, these procedures may show up a leak in your system or indicate that you need new radiators. This procedure is also known as a Powerflush and costs between £300 – £600 on average.


If left, these contaminants can dramatically affect the overall efficiency of the heating system. In more severe cases, only a powerflush will work. Over time water present in your radiators, boiler, and pipes will deposit byproducts such as rust. The debris, dirt, and rust turn into a mud-like unpleasant substance that most professionals call "sludge". 


Sludge in a heating system often causes corrosion and blockages that either lead to the breakdown or inefficiency of the system. In very extreme cases, the effects are so damaging that a boiler replacement may be the only option. 


When Is A Powerflush Needed?

If you stick to regular maintenance and servicing (professional servicing should be carried out annually), then the preventative Powerflush only becomes necessary every 5 to 6 years to make sure the debris is completely cleared out and to prevent a blockage that is starting to take hold. 


However, this will also depend on the system type. For example, boilers that still use the copper-heat exchangers as opposed to the stainless steel types generally corrode faster. 


Important Tip: If you plan to replace a boiler it is vital that your engineer provides a Powerflush service before installing the boiler. If you fail to take this step, there are risks that your new boiler will become contaminated with the debris and sludge that is still in the existing pipework. 


Signs That Your System Needs A Powerflush


There are a few signs that will suggest that a central heating system is not operating as it should:


Cold spots or areas on your radiator, usually along the bottom

Excessive noises from the heating-system pump or the boiler

The water is discloured when bleeding the radiators

The heating takes a long time to warm-up

There is limescale in your system (cloudy tap water)

Some of the radiators are don't heat as well when compared to the others

The boiler shuts down regularly and requires restarting

The pipes are hot but the radiators are cold

No water comes out when bleeding the radiator

Noisy boiler and/or radiators

The radiator has sprung a small leak


Find out ways to keep sludge levels to the bare minimum in Water Treatment in Heating Systems. 


If you have noticed one or more of these issues, you should contact an engineer. While a Powerflush might be what the system needs, it is often more complicated than that. The system may have experienced significant damages that it may be a more cost-effective option to replace the system. If this is the case, you should contact 2 or 3 professional companies to ensure you are getting the right price. 


The Benefits Of A Powerflush


The main benefits of getting a Powerflush for your heating system include:


Your radiators will start heating up faster

Quieter boiler/radiators

Your radiators will start getting hotter

Increase the energy efficiency of the system which translates into lowered energy bills

Increased hot-water temperatures

Increase the life-span of the heating system

More reliable, reducing the likelihood of a breakdown


How Is A Powerflush Carried Out?


A qualified and experienced engineer connects a pump directly to the central heating system. If you have a combi boiler the pump connects at the head of the pump. For system boilers, the pump connects directly to the circulation pump. This pump then pushed specialised chemicals through the radiators, boiler, and pipes. 


One of the chemicals used removes the rust and sludge, while the descaler removes any limescale. There is also a corrosion inhibitor that stops further rust from developing. The engineer then collects and safely disposes of the contaminated water, particles, or debris that was extracted from the central heating system. 


The engineer will also use equipment and special tools on the outside of the radiators to dislodge a stubborn blockage. They will usually take a measurement of the temperature of the radiator before they started working on it, and then after to show the overall improvements after the Powerflush. 


The entire process can take between 6 to 10 hours which will also depend on how many radiators you have, how much sludge is present in your system, and how old your radiators and boiler are. The engineer might find other problems during the process such as having to replace certain parts, especially those that cannot be repaired. Most of the Powerflush jobs take place in a day, but for more severe scenarios, this can take longer. 


Qualified engineers have the skills and experience to carry out replacements, a Powerflush, and repairs. 


Who Should Be Carrying Out A Powerflush?


Not every company performs a Powerflush to the required standards. There is also a diverse range of equipment and chemicals available, and with all other industries, the providers are also associated with different levels of attention-to-detail and expertise. 


This is why it is best to check on independent and reliable review sites or request a customer recommendation. We suggest sourcing 3 to 4 quotes from different professionals, to compare the services and costs. 


Is It Possible To Perform A DIY Powerflush?


It is definitely not advisable. 


While it is possible to hire a Powerflushing kit and to watch instructional videos, it is a complicated and very risky job. Professionals often make Powerflushed look safe, clean, and easy, but this job can become very messy and even dangerous. Specialist equipment and chemicals should be handled by people that have the training to work with these tools. 


If you decide to carry out this type of work on a heating system, it could invalidate your manufacturer's warranty. An experienced and knowledgeable engineer will also provide a certificate that proves that your Powerflush was carried out by a professional. This is essential when you need this proof for an insurance provider or manufacturer. 


Ultimately, if this work is not carried out correctly, it may end up causing even more damages than you started with. 


NOTE: The installation of a magnetic filter won't provide the benefits that a Powerflush procedure will. However, it can provide protection to the system by preventing future sludge build-ups or blockages. 


How Much Does Powerflush Cost?


Many factors affect the prices of a Powerflush. For example, the complexity and size of a heating system, along with any incidental issues that may crop up during the procedure. A Powerflush typically costs between £300 to £1000+, and can also vary from one engineer to the next. In some cases, there are other costs involved such as replacing the TRVs or the need for more descaler chemicals. 


Your central heating system should be running at optimal levels all the time, and even though a Powerflush may appear to be expensive, it can end up saving you lots of money over the long run by reducing your heating bills. 


Is A Powerflush The Best Solution?


In extremely severe cases, it may be a more cost-effective option to replace your system rather than carrying out a Powerflush. A Powerflush won't repair or fix any broken parts. If the blockage has caused parts to break, this will end up adding costs and time to the job to get your system back to optimum levels. Only a professional engineer will be able to tell you when this happens to be the case.


keep your family safe from the dangers of faulty gas appliances

Gas Safe Registered Engineer

You should never allow anyone who isn't suitably qualified to service or install any appliance that uses gas in your home since this will drastically increase your risk of getting carbon monoxide poisoning. This particular gas is very toxic and can easily kill you without warning because it is not possible to smell, see or even taste carbon monoxide.

The official gas safety body for the United Kingdom is Gas Safe Register which was also called CORGI in the past. So, if you do need to hire someone to handle gas in your home, then you need to hire someone who is on the Gas Safe Register.

If you need someone to fix or diagnose your heating system, then you should only hire boiler engineers that are also on the Gas Safe Register. If they present a CORGI card, then they are likely not registered and you shouldn't hire them because they are not legally qualified to do this type of work.

Make sure to check the engineer's membership card and ensure that you look for the Gas Safe Register symbol which is a yellow triangle as opposed to an orange badge which is representative of CORGI.


10 Tips For Gas Safety

1. Check your appliances that use gas yearly

If you are disabled, have a means-tested benefit, have a chronic illness, or at the age of pension, then you are actually entitled to getting a completely free yearly gas safety check. So, if you want to know if you qualify for this free check, simply call your local energy company to find out.

2. Make sure that the engineer is Gas Safe Registered

In Guernsey, Isle of Man, or the United Kingdom, it is illegal for any individual to work with gas if they are not Gas Safe registered. As a result, before you allow any engineer into your property, make sure that they are on this register by either checking the official website or even call 0800-408-5500.

All engineers that are Gas Safe registered will have an ID card by Gas Safe.

Keep in mind that there are various types of registration. So, there are engineers who are only registered and qualified to work on gas fires but are not qualified and registered to work on pipes or boilers. Make sure that you thoroughly check the front and back of the card to make sure they are registered to do the type of work that you've called them to do.

3. Gas Safe Registered Business employees cannot do private work and it is illegal for them to do so

It is illegal for you to privately hire any person who is Gas Safe Registered and works with a Gas Safe registered business. While you may think it is a smart idea, it definitely isn't.

4. Always report any person who you think may be working illegally on gas

If you believe that someone is doing any type of gas work illegally, make sure that you call and report that person or persons to the Gas Safe Register.

5. Get an inspection for your gas work

If you've had gas work completed on your property within 6 months, you'll be able to nominate it for a free Gas Safe safety inspection. This inspection will check to make sure that your gas work is up to standard.

6. Make sure to get your appliances tested if you've moved

Whenever you move into a new house, you shouldn't automatically believe that all of your appliances are fine and safe. Make sure that you get them thoroughly checked out by a Gas Safe registered engineer.

7. Be aware of carbon monoxide poisoning and the common symptoms

It is important to know the signs of carbon monoxide poisoning since this knowledge cans ave your life or the life of your loved ones. The signs include:

- breathlessness

- dizziness

- headaches

- nausea

- loss of consciousness

These symptoms may improve when you leave your property and then start again when you are back in your home. Be conscious if more than one person is also experiencing these issues within the home, especially at the same time.

8. Be knowledgeable on what you should do if you believe yourself or someone else is suffering from carbon monoxide poisoning:

- Open all of the windows and doors and try to get fresh air as quickly as possible

- Exit the house

- Switch off any appliances that use gas as well as turn off the gas

- Make sure there are no naked flames in the house and turn off any if necessary

- Go to your doctor or a hospital. Make sure that you let them know that you believe you may have carbon monoxide poisoning. You should also call the Gas Emergency Helpline at 0800-111-999

9. Look for signals that your gas appliances aren't functioning well

Many signs may indicate that your appliances aren't working as they should; these include:

- Black marks around the appliance

- Issues with the pilot light going out often

- Orange or yellow flames on your stove since they should be blue

- A lot more condensation on the interior of your windows

10. Install a loud carbon monoxide alarm

Since it is not possible to see, taste, or even smell carbon monoxide gas you should get a carbon monoxide alarm to let you know when this gas is present for protection. These alarms are very similar to smoke alarms and they are simple to install. They typically cost under £20, however, you should only purchase a carbon monoxide alarm that has a European or British seal-like Kitemark.

Gas Safe Register Defined

This body was created in 2009 and replaced the previous gas safety body known as CORGI Gas Registration. This company has been in existence for over 17 years and successfully lowered domestic gas safety problems in this period.

However, in 2006, this body was reviewed by various gas engineers, stakeholders in the industry, consumers, etc and they determined that even more could be done to progress in this industry through reform. So, in 2008 the HSE or Health and Safety Executive allowed the Capita Group Plc to create a new registration for all gas engineers. As a result, the Gas Safe Register was formed and they have been working hard toward increasing gas safety for engineers as well as the entire public.

Poisoning by carbon monoxide

Every year, about 50 people are killed by carbon monoxide poisoning within their homes. Also, every year there are over 200 people who suffer from health issues due to exposure to carbon monoxide. As a result of this, you must be aware of the risks of this gas and how to prevent getting poisoned by it.

This gas is so dangerous because humans can't sense it via smell, sight, or hearing. Therefore, you need to be aware of the symptoms of CO poisoning such as breathlessness, headaches, feelings of nausea, dizziness, loss of consciousness, etc. Once you notice these symptoms only happening while you're in your home, then you're likely dealing with a CO leak which has to be fixed asap.

About the Author


Heat Quick Direct are Vaillant accredited engineers

Heat Quick Direct is accredited by all the major gas boiler trade bodies, such as Gas Safe and we are approved G3 unvented hot water storage engineers approved by Worcester as accredited engineers and we are approved advanced Vaillant engineers.