Best Combi Boiler – Find the Best for your Budget
Follow our step by step guide to find your best combi boiler:
How to use this Guide
Follow these instructions to get the most from our best boiler tables:
1. Pick your property size from the drop down tables below. NB if you have multiple bathrooms, you can opt for the next property size up in order to achieve better hot water flow rates. For example if you have a 3 bed house with 3 bathrooms, with showers that often in use at the same time, you could consider one of the boilers in the 4 or 5+ bed category.
2. Do you need a boiler that will fit in a cupboard? If you are installing your new combi boiler in a kitchen cupboard you will need a compact boiler.
3. Is the length of manufacturer cover important to you? If you are moving in a few years perhaps you do not need one of the more expensive boilers with a 10 year warranty; a budget end boiler with 5 a year warranty will do and save you £500.
4. Is boiler efficiency a big factor in your boiler purchase? If so, you can use the tables to find the most efficient boiler in its budget group. NB these are 'factory tested' efficiencies and are only achieved when the boiler is operating in what is known as 'condensing mode'. Due to oversizing in boilers this rarely happens.
5. Finally, litres per minute for hot water – this is how fast the boiler can heat cold water. The smaller boilers will always be around 10 litres per minute, the bigger boilers over 16 litres per minute. Litres per minute is important if you and your family have multiple bathrooms and shower at the same time in the mornings.
What size combi boiler do I need?
The average UK home requires no more than 6-8kW of heat at peak times, i.e. on a cold day in February. Stated outputs for combi boilers are 24kW and upwards, which seem enormous. However these are for hot water production. For heating the output are lower but not by much, the smaller boilers start at 18kW which is still three times the size of most homes.
For combi boilers it is best to factor hot water production into your decision and just make sure the boiler, whichever one you pick, can be adjusted down (called range rating) to meet your heat requirement. This must be done by a competent gas safe registered engineer. Note however that really large combis will not adjust down low enough and will therefore prove very expensive to run. If you have multiple bathrooms in use at the same time opt for a system boiler with hot water cylinder.
For more on boiler sizing try our Guide to sizing your boiler. For more on the important role balancing and heating controls play in getting the most efficiency from your system, read our blog: Why oversized boilers are bad for your bank balance and the planet.