Heat only boiler size guide

Choosing the right heat only boiler for your home is crucial for efficient heating and energy cost savings. Whether you have a small apartment or a large house with multiple bathrooms, various factors must be considered when determining the size of your heat-only boiler. 

This guide will help you understand the different boiler sizes available and how to select the ideal one based on your home's heating demands. From the recommended kW outputs for various home sizes to the importance of balancing efficiency with power, learn everything you need to know to make an informed decision.

If you are looking for more information, our handy blog on the advantages and disadvantages of heat only boilers is here to help. 

What is a Heat Only Boiler?

Heat-only boilers are a common feature in many older UK homes, especially those constructed before the 1970s. If your heating setup includes a hot water cylinder and two water tanks (usually located in the loft), it’s likely you have a heat-only boiler. These components collaborate to supply hot water to your radiators, taps, and showers. 

For a deeper understanding, check out our blog post, 'What is a Heat Only Boiler,' for more insights.

Still unsure which boiler you need? Read our blog on differences between a Combi, System and Heat Only boilers. 

What Factors Affect Boiler Size?

Once you have selected the boiler type for your home, you will need to choose the correct boiler size for your home’s heating requirements. A few factors to take into account include: 

• The number of radiators

• Number of bedrooms

Number of bathrooms What Size Heat Only Boiler Do I Need? 

Heat only boilers store water ahead of time, meaning they are built with a smaller power unit than combi boilers. Below we have shared the ideal boiler size depending on your home’s heating requirements. 

Please note these are general guidelines for what size boiler you should have. We always recommend consulting a trained Ideal Heating engineer before making a final decision. 

Size of Ideal Heating Heat Only Boilers

See the different sizes of heat only boilers we offer. 

Discover more top tips on the Ideal Heating Blog, or for further advice on choosing the best heating system, use our boiler selector tool. Also, if you encounter any issues with your heat only boiler, head to our troubleshooting guide.