Do You Know What Size Of Boiler You Need For Your Home?
- A smaller house or flat with less than ten radiators and one bathroom needs a boiler between 24 and 27 kilowatts (kw).
- A larger three bedroom semi-detached house with up to 15 radiators and two bathrooms will need a 28 to 34kw boiler.
- A large house with as many as 20 radiators and two bathrooms will need between a 35 and 42kw boiler.
What Size Boiler Do I Need?
If your boiler is on its last legs and needs to be replaced, buying a new one is going to set you back several hundreds of pounds.
We generally put a lot of thought into what sort of fuel we want our boiler to run on, less thought into how much power we want it to be capable of producing.
The power or heat which the boiler can produce is known as its capacity, and the decision about what capacity of boiler best meets your needs will depend on a number of factors so when asking yourself what size of boiler do I need consider the following:
Boiler Sizing - Bigger is not Better
The temptation can be to opt for a higher capacity boiler, in the mistaken assumption that a bigger boiler produces more heat and will therefore heat the house more quickly.
This is in fact not the case. Boilers which are “oversized” create a great deal of waste energy, as they produce more heat than can be pushed out through the radiators.
Any excess heat generated by a boiler which is too big will disappear out through the flue into the open air, however efficient the boiler’s certificate says it is.
Know The Averages (Rule of Thumb Sizing) When Choosing A Boiler Size
When thinking about what size of boiler you need, the first step is to go around the house and count up the number of radiators you have, as well as the number of bathrooms where you require hot water to be provided on demand.
A smaller house or flat with less than ten radiators and one bathroom needs a boiler between 24 and 27 kilowatts (kw), a larger three bedroom semi-detached house with up to 15 radiators and two bathrooms will need a 28 to 34kw boiler, and a large house with as many as 20 radiators and two bathrooms will need between a 35 and 42kw boiler.
This should provide the starting point for your search.
Future Plans For Expansion
Once you have looked at the average size of boiler needed for your property, it is wise to consider what plans you have for future renovations on the property.
If you are planning on converting a loft or garage, or thinking about adding another bathroom in the future, it might be best to consider a slightly larger boiler which will cope with additional radiators in the future.
A good heating engineer will be able to recommend a boiler based on your current and future requirements.
Online Boiler Sizes Calculators
Many of the major boiler manufacturers or installers such as Vaillant, Worcester Bosch and British Gas have calculator tools on their website which allow you to put in details about the size of your house and number of radiators and get recommendations about the best boiler for your needs.
The disadvantage of these is that they often do not allow you to compare boilers from different brands and do not always take every eventuality into consideration.
Online calculators should be treated as a good starting point, but are never a substitute for a home visit from a reputable heating engineer.
