Boilers

Shop high-quality boilers from trusted brands like Ideal Boilers, Vokera, Vaillant and Baxi. At Toolstation, you’ll find gas combi boilers and system boilers compatible with most central heating systems.

What Are the Different Types of Boilers?

Combi boilers are a popular choice for many homes, heating water as you need it. They are smaller and more compact than system boilers, making them easier to install in any property.

System boilers store hot water in a cylinder after heating it, producing higher volumes on demand. They can be helpful for homes with two or more bathrooms. However, once the hot water supply has been used up, you’ll have to wait for the boiler to heat more.

Browse our full range of boilers and related accessories here, or check out our Boiler Buying Guide for more tips and advice on finding the right one for you.

How do I size a boiler for a house or building?

Boiler sizing depends on your heat load: number of radiators, insulation, number of bathrooms, and hot water demand. 
Use kW rating - oversize slightly rather than undersize, but avoid huge overspec. For instance, a mid-size home might need 24–30 kW for a combi boiler. Consult heat loss calculations or use a rule of thumb per radiator/room.

Can I swap one boiler brand for another?

Yes - in many cases you can - but ensure compatibility: flue position, gas supply, pipework routing, control connections, and warranty implications. Reusing existing mounting, boiler room layout, and condensate routes can reduce installation challenges.

How often should I service a boiler?

Servicing your boiler annually is standard for most boilers. Regular servicing helps maintain efficiency, catch faults early, ensure safety, extend lifespan, and keep the warranty valid. Also check for leaks, carbon monoxide safety, flue integrity, pressure, and proper burner operation.