Can't decide which system is right for you? Getting confused? Hopefully this page will help you to decide. Combi or Conventional?


The answer might not be as simple as it sounds. You have to bear in mind that with the combi boiler the hot water is being heated instantly on demand. If you have a large property and the most used areas of the house (in terms of hot water usage of course) are far from each other and the location of the boiler is also far from them than probably it is not a good idea to install a combi boiler. There are a lot more factors to be taken under consideration when thinking about installing a combi boiler. Read on...

comi vs conventional


How do combination boilers work?

Combination boilers work by delivering hot water directly from your mains water. The mains water enters the boiler and is heated up by a heat exchanger instantly, which then delivers hot water to your taps.

Whats the catch?

The one downside of combination boilers is they are dependant on the water pressure. You need minimum 12 litres per minute of flow coming from the mains water supply. They are generally referred to as 1-2 tap operational systems. So if you have 12 litres per minute coming out your tap as soon as you open a second tap that flow will be halved, so both taps will have 6 litres per minute instead of one having the full 12 litres.

The more flow you have coming in from your cold water supply the better the performance. Water flow from the mains can vary from 9-18 litres per minute in Cambridge. 

Key questions to determine weather a combi boiler is for you or not:

  • How many bathrooms do you have?
  • How many people live in the house?
  • What are the chances or two people showering at the same time / daily routines?
  • Do you plan to extend your home ?
  • What is my mains pressure and flow rate?
  • What is the proposed location of the new combi boiler relative to the hot water outlets?

You should always contact a professional to all the above measurements in order to help yo decide which system you are going to be using.


Combi vs conventional chart



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