Boiler Size

Boiler Size

Most manufacturers make each of their boilers in a range of different heat outputs, typically ranging from 12 to 40kW.

A higher number means a boiler can heat water more quickly, so it can supply hot water to more radiators or taps. The greater the number of radiators or taps you're likely to use at a time, the higher the boiler kilo wattage you're likely to need.

As homes have vastly different numbers of radiators and bathrooms these days, it's difficult to generalise about what size boiler is needed for a flat, cottage or larger house. Your boiler will be sized according to the amount of heat and, in the case of a combi boiler, hot water you require.
More important than selecting boiler size is choosing the actual boiler type - combi, system or open vent - depending on the households heat and water needs - and of course deciding whether to change the system layout, especially when considering the budgeting of the installation
If pricing new boilers there is little difference between, for example - a 15kw or 18kw system / open vent boiler.
The same applies with combi boilers - there is little difference between a 24kw and a 27kw model.

Your installer will size the boiler according to how many rooms and radiators you have, as well as the number of hot water taps or devices that use hot water.

When buying a new boiler you'll need to get your hot water demand assessed individually by your plumber or installer.

 Useful Links

( Model numbers are a little confusing but you can see recommended combi, open vent or system boilers & sizes )
( Method requires details of house build, house size & construction. As used by heating engineers )

Contact Details

Simon Mason 

mobile - 07783146897
landline - 01733 755667 
Energy Efficiency Qualified - Part L - Heating Engineer
Gas Safe Register has now replaced Corgi Gas - the regulator for gas engineers