Combination boilers are by far the most popular boiler type, accounting for over half of all new boiler sales within the UK.

Most wet central heating systems use a boiler to heat a copper cylinder in the airing cupboard to provide hot water. A combination boiler (usually referred to as a ‘combi’ ) heats water for the taps from within the unit and combines this with central heating.

Combi boilers don’t need a water cylinder on a cold water tank to feed it. Hot water running costs are therefore slightly lower. The water is heated as you use it and doesn’t sit in a cylinder which is gradually going cold. Depending upon the water pressure at your home, today’s combi boilers can produce flow rates similar to stored systems.

In homes where a number of taps and showers are likely to be used at the same time, we can advise you on whether or not the combi is suitable. Showers fitted to this boiler must be a ‘mains pressure’ type.
Because combi boilers are fed directly with mains cold water, there must be enough water pressure for them to work properly. Manufacturers state what the minimum pressure should be for each model.

Types of combi boilers
A combi (instantaneous) boiler is the most widely used type and directly heats incoming mains cold water to supply hot water to taps and showers.

A combi (instantaneous condensing) boiler operates in principle as an ‘instantaneous’ type but at somewhat higher efficiencies (see condensing boilers)

A combi (storage) boiler is a variant of the Instantaneous type and is designed to give better hot water performance. Dependent upon the make and model, the improvement in hot water delivery will depend upon the size of hot water store, and this can vary considerably.

The stored water will provide an improved initial hot water delivery and once this has been used the boiler then operates as an ‘instantaneous’ type.

A combi (storage condensing) boiler operates in principle as a ’storage’ type but is more efficient.

Combined Primary Storage Unit (CPSU) - This is a special category of storage combi and incorporate a very large store of water (usually more than 80 litres) which creates a high hot water flow rate to taps and showers and heats up radiators quickly.

We are Happy to provide a free, no obligation survey and quotation,

Just call (freephone) 01737 224425