What size boiler do I need?

#Buying Guide

How to choose the right size boiler for your home.

Knowing which size of boiler for your home depends on a multitude of factors but general estimation is for most small to medium sized properties (such as flats and small houses) to have up to 10 radiators and 1 bathroom. A property of this size will commonly need a combi boiler with a 24-27kw output. Larger properties 4+ bedrooms are likely to have 10-15 radiators and perhaps 2 bathrooms, which requires a lot more power in the range of 28-34kw.

How do you work out what size of boiler is required?

The size of boiler needed for your property is dependent on many factors, including;

  • Size of property - If the property has a large footprint with more space that needs to be heated. Alternatively, smaller homes don't require the boiler to work as hard to keep it warm.
  • Number of radiators - Properties with a small number of radiators connected to the heating system are likely to warm up a lot faster than properties with lots of radiators because there is less water/radiators to keep warm.
  • Number of bathrooms - The more bathrooms a property has, the more energy is required to heat them. As well as how many showers you are likely to be running off the boiler at any one time.
  • Usage - If you have a large family living in your home, then at peak times you may have high demand hot water (both/showers/heating).
  • How many floors the property's heating system covers - Most properties tend to be on 1 or 2 floors. However, modern and historic properties such as townhouses may have 3 or 4 floors, as there is more height in these properties, the system may require greater water pressure to ensure that the circulation is properly maintained.

How does BOXT work out what size boiler I need?

Customers of BOXT can simply visit Find-a-Boiler on the website and answer just a few questions about the property and heating needs. The website will then reveal a number of boiler options best suited for the property based on the boiler manufacturers recommendations, along with your fixed price (with no hidden charges or extra fees!).

What happens if I pick the wrong sized boiler?

It is likely that the boiler will still function, but it won't deliver the results that you need. If you have too small a boiler for too many radiators, the boiler may be put under too much pressure and now have enough power to heat all of the radiators adequately. As long as you chose from the list of recommended boilers you can be sure that the boiler will be suitable for your needs.