
When you are looking to buying a new boiler it can be quite a confusing situation, for starters what size does my boiler need to be, buy one too big and it will higher your gas bill, buy one too small and it will not heat your home sufficiently. So you need advice to know which one will suit your hot water and heating requirements.
There are three main size ranges in a combi boiler
- 24 to 27 kw combi boiler size
- 28 to 34 kw combi boiler size
- 35 to 42kw combi boiler size
Sizes 24 to 27 kw Combi Boiler
As a rough guide a smaller house such as a terrace or small semi detached you will run up to10 radiators and I bathroom and a 24 to 27 kw boiler will suit this home. The main issue that will put a combi boiler under pressure is the amount of water that you need to consume at once. If you had two bathrooms that were in use at the same time you may need to get a larger boiler to cope or a system boiler with a tank may suite your requirements better.
Sizes 28 to 34kw Combi Boilers
For a medium to large 3-4 bedroom house such as a larger semi, terrace or detached house you will have up to 15 radiators that need heating, hence you will need a larger boiler. As a larger family your water consumption will go up so you may have two bathrooms so a larger boiler 28 to 34kw would be suitable.
Sizes 35 to 42kw Combi Boilers
A detached larger house will have more radiators up to 20 radiators and a larger boiler will be needed to run the heating in this home, and the water requirements could be even greater A 35kw and a 42kw Combi boiler can cope with this demand.
When Do You Need A System Boiler
When you may need a system boiler is when you have a higher demand for hot water with a busy family at certain times of the day you will need a large supply of hot water, a system boiler has the added benefit of a water cylinder to store the hot water in..
For properties where a higher demand of hot water is needed the higher the kw of the boiler, the better the flow rate of hot water will be.
What Is A Combi Boiler?

A combi boiler is a single unit that will heat both your hot water and your heating from on single unit. It heats the water direct from the mains without any need for a separate storage tank. This is a great space savers in the modern household where space is of a premium.
