Boiler Capacity Calculator
Calculate the heating capacity and hot-water flow your home needs, then see boilers matched to your required output. Factor in ceiling height, bathrooms, and climate.
2,200 sq ft
2 bath
114,000 BTU/hr
Recommended capacity (heating + headroom)
Heating load99,000 BTU/hr
Suggested DHW flow4.6 GPM
Combi suitable?Yes — combi works
Frequently asked questions
What is boiler capacity?+
Capacity is the boiler’s heat output (BTU/hr) plus, for combi units, its domestic hot-water flow rate (GPM). Both must meet your home’s peak demand.
How many GPM do I need?+
Roughly 2 GPM per simultaneously-used fixture. A single combi typically handles up to ~5.5 GPM; beyond that, consider a storage combi or heat-only boiler with a tank.
Ready for the next step?
Get matched with approved local installers and real quotes.