Boiler Types Explained | Combi, Heat Only & System
Summary of Boiler Types
What is a combi boiler?
A combi boiler is a single unit that generates all the heating and hot water for the home. There are no hot water tanks. How much is a combi boiler? Read our guide to Combi Boiler Prices
What is a heat only (regular) boiler?
A heat only boiler only provides heating. It works with a hot water cylinder. How much is a heat only boiler? Read our guide to Heat Only Boiler Prices
What is a system boiler?
A system boiler has all the same components as a combi boiler without the hot water production. It works with a steel hot water cylinder. How much is a system boiler? Read our guide to: System Boiler Prices
How to use this Guide
Advantages of a Combi boiler
- Creates space when removing old hot water tanks
- Lower maintenance costs - the integral heating and hot water functions are covered by the boiler manufacturer's warranty/guarantee
- No long wait times for hot water
Disadvantages of a combi boiler
- They do not work well in properties with poor flow rates and/or poor incoming water pressure
- Hot water flow rates are reduced when providing hot water to two or more outlets simultaneously, although this is really only a problem in houses with two or more showers.
- High-performance combi boilers - that provide 12.5 litres per minute of hot water or more - may not be effective on 15mm pipework supplies and can be oversized for the heating - for more on the appropriateness of combi boilers see our Guide to Boiler Sizing