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What is a conventional boiler?

For anyone in an area with low water pressure, a conventional boiler could be the perfect choice. Unlike combi boilers, they require both a hot water storage cylinder and a water tank and can provide large volumes of hot water to multiple bathrooms. They’re also known as heat only boilers, traditional boilers, open vent boilers, and regular boilers, and are a great option for older homes with lots of extra space.

How Does a Conventional Boiler Work?

Cold water from the tank is heated up in the hot water storage cylinder, which feeds into the household’s taps and faucets. Conventional boilers are either sealed or open vented. In sealed systems, the boiler doesn’t have a feed and expansion tank and is closed to the atmosphere, whereas open vented systems are open to atmospheric pressure and do have a feed and expansion tank, helping to accommodate water loss from leakage or evaporation. The water tank in the loft maintains the right water level whilst a pump circulates the hot water to your home’s radiators.

Conventional boilers can provide water to multiple bathrooms at the same time, so if you’ve got a large and busy family, this might be your ideal home heating solution. In addition, they’re a great choice for homes which have older radiators, as they may not cope well with the higher water pressure supplied by system or combi boilers. A conventional boiler should also be the first choice for homes which already have a conventional system in place as relatively little pipework will need to be replaced, making the installation process quick and easy. Finally, conventional boilers are compatible with solar heating systems, allowing you to lower your carbon emissions and saving on energy bills.

Why choosing the conventional right boiler is important

Choosing the right boiler will ensure that your home is heating efficiently without any energy wastage. The wrong type of boiler will lead to high energy bills and long delays in hot water reaching your home’s outlets. It’s always important to double check which boiler directly suits your home based on its layout, but don’t worry; we can help with that.

Conventional boilers can heat homes with up to 7+ bedrooms and more than one bathroom. If your home is large in size, you can still enjoy hot water from all outlets without the flow of water getting weaker. Unlike combi boilers, conventional boilers heat incoming water to then be stored in a hot water cylinder for later use. Be aware though that you will need to programme your boiler to heat the water in your cylinder, so you have plenty for when you need it.

How do I know if a conventional boiler is right for my home?

There are a few ways to tell if a conventional boiler is suitable for your home. The most obvious way to tell is the current layout of your central heating system. If your home only has a boiler, and hot water cylinder installed but doesn’t have a loft-installed tank, your current boiler is a regular boiler. Like-for-like regular boiler swaps tend to be a lot easier for engineers.

Regular boilers are the most traditional form of heating in the UK. Although they are still in use today, their popularity has fallen recently in favour of combi boilers. Despite this, a regular boiler could still serve your heating needs effectively. There is also a feed and expansion tank, located in your loft, which is filled with water. It keeps your heating system’s water levels relatively constant. It also incorporates a safety device whereby if there is too much hot water in the system it will fill the tank then exit through the overflow.

What are the Advantages of a Conventional Boiler?

The greatest advantage of installing a conventional boiler is that it can produce high volumes of water to multiple bathrooms at the same time, making it perfect for larger families. Some of the other advantages of this type of boiler include:

  • Easy installation in homes with traditional heating systems
  • Perfect for older homes in areas with low water pressure
  • Small leaks are generally not a large problem, and won’t cause a loss of pressure in your shower
  • Compatible with solar thermal systems, making them a very energy-efficient option and enabling you to cut down even more on carbon emissions

What are the Disadvantages of a Conventional Boiler?

It’s important to consider the potential drawbacks of installing a conventional boiler – they aren’t the most efficient boilers for every household:

  • Can be more expensive to run
  • Require space for both a hot water storage cylinder and a tank
  • Installation can end up being more expensive than other types of boilers
  • A water tank boiler may need time for the water to heat up
  • Only provide access to as much hot water as your tank is able to hold

Condensing Conventional Boiler

Outside of exceptional circumstances, all boilers installed in the UK must be condensing, which means that if you install a conventional boiler today, it will be a condensing boiler. These boilers extract heat from flue gases (which would otherwise escape into the atmosphere) and recycle it, saving energy and money in the process. In addition, conventional boilers are compatible with solar water heating systems, making them a good choice for environmentally-conscious homeowners. An increased level of fuel efficiency in your home heating system can help you to save money and reduce your carbon footprint.


Conventional boilers aren’t the most effective choice for every household. They require more space than every other boiler, which is why smaller properties might benefit from installing a combi boiler or a system boiler instead.

Combi boilers are an all-in-one home heating solution operating from one heating unit. They don’t need a tank or cylinder, making them perfect for smaller homes, and automatically respond to taps being turned on by sending hot water through the system. However, they can’t run hot water to more than one faucet at a time, so if several are used simultaneously, the water pressure is likely to drop.

System boilers are similar to conventional boilers, but they don’t need a loft tank, just a cylinder; all of the key components are actually built into the boiler. This makes them a more intuitive choice for smaller households since the installation will be quicker and easier, while their ability to provide hot water to multiple bathrooms at the same time is great for homes with high water usage and multiple bathrooms.

If you would like to know more about alternative types of gas boilers, check out our boiler guide.

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