Combination boiler

Combination ("combi") boilers combine a boiler heating primary water for Central Heating with the facility to heat Domestic Hot Water for washing etc.

Most combis also contain components to make a sealed primary system thus requiring the addition of little more than pipework and radiators to make a simple central heating system. However this simplicity of installation comes at the price of the boiler being a single point of failure in the system, with repairs usually being more expensive than for a system built out of discrete components, as well as a limited rate of hot water supply.

For a discussion of all types of boiler see Ed Sirett's Boiler Choice FAQ