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Boiler size calculator

Which Glow-worm boiler is right for your home?

We know that trying to find the right boiler for your property is a difficult thing to do, so we have designed this boiler size calculator to help you find the boiler best suited for your home. Once you have submitted a few details about your property and the amount of occupants currently living there, our calculator will give you a suggested heating appliance for your home. If you are happy with the suggestion that has been given to you, feel free to get in touch with a local installer through our Find an Installer tool to enquire about it!


Combination boilers

Choose our convenient solutions for smaller households to benefit from hot water on demand and a perfectly heated home.


View our combi boiler range

System boilers

These boilers are fitted with a cylinder to provide steady hot water and a comfortable home temperature.


View our system boiler range

Regular (open vent) boilers

Offering unrivalled comfort with a continuous hot water supply and the perfect temperature in large households.


View our regular boiler range