Boilers - central heating and hot water for your home

Gas-fired condensing boilers are more energy efficient compared to their traditional counterparts. Modern gas boilers use supplied energy as well as thermal energy to provide heating and hot water for a range of homes.

The thermal energy is contained in the flue gas that is otherwise lost when it exists out the flue pipe.

The advantages of a gas condensing boiler to older heating technologies:

• Optimum energy efficiency of up to 98%
• Significantly less soot during combustion
• Energy consumption drops by up to 30% compared to an old heating installation
• Low investment costs, often quick to install
• Flexible expansion, e. g. with solar collectors, heat pumps, cylinders and controls
• Suitable for hot water supply as well as heating

A simple guide to the different boiler types

Combination (combi) boilers

Combination boilers (combi boilers) do two things, heat water and provide central heating.

Combi boilers provide hot water on demand minimising the need for a hot water cylinder. The boiler is connected directly to the water mains, meaning it only heats water as and when it's needed.

If you are in need of hot water at any time without worry, a combi boiler will likely be the best choice for your home. Another benefit is the lack of a water storage tank means that you’ll save space in your home too.

Homes which suit combi boilers

Modern combi boilers are highly energy efficient and compact. They don't require a water storage tank or a hot water cylinder, making them ideal for properties with limited space. They provide best-in-class energy efficiency combi boilers are one of the most popular boiler types fitted in the UK today.

Note that for larger households with multiple bathrooms in active use, the delivery of hot water can be affected when more than one hot water tap is in use simultaneously. Furthermore, homes that have poor incoming water pressure and/or flow rates could struggle to efficiently utilise a combi boiler. A certified engineer can assess the viability of a combi boiler in your home during a visit.

For more information, read our complete guide on combination boilers.

System boilers

System boilers, also known as sealed system boilers, need a water cylinder to store hot water, however there’s no need for a hot water tank in the loft. The heating system is built into the boiler itself, unlike regular boiler systems. These combine the benefits of a regular open vented boiler with a space-conscious combi boiler.

Homes which suit system boilers

System boilers are ideal for homes with more than one bathroom, as they provide a constant supply of hot water to any number of taps at the same time. However, they are space-conscious enough to warrant an internal water tank.

Furthermore, as all the necessary components for the heating system are built into the system boiler itself, this type of boiler is less susceptible to frost build-up. If you live in a particularly cold climate, where an attic water tank could be negatively impacted, a system boiler would be a better solution for your home’s heating requirements.

For more information, read our complete guide on system boilers.

Regular boilers (open vent)

Regular boilers, sometimes known as open vent boilers, heat only boilers or conventional boilers, provide central heating and hot water through a hot water storage cylinder.

The cylinder is often found in an airing cupboard and the cold water tank is usually found in the loft. Typically, older homes that have traditional heating systems will contain a regular boiler installed.

Homes which suit open vent boilers

If your home has multiple bathrooms, open vent boilers are perfect as they can provide a lot of hot water at the same time. Open vent boilers work well if you are replacing an old open vent heating system, and ideal if water pressure is low in your area.

Note that they do require more space than other boiler systems, due to the necessity of a separate water tank - often placed into an attic or loft space.

If your home has particularly old radiators and heating pipework (25 years old+) and a small hot water cylinder in the airing cupboard, chances are you already have an open vent boiler.

Open vent boilers work on a much lower system pressure than that of a combi or system boiler. Combi and system boiler types produce much higher system pressures when operating, this increased pressure can cause leaks and damage when fitted to older systems.

If your old boiler requires regular maintenance, it is often advised to replace it with another open vent boiler as you should not have to replace existing radiators and pipework. It's important that any changes to your heating system are carried out by a gas safe heating engineer.

For more information, read our complete guide on regular (open vent) boilers.

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