Combi Boilers

A combi (combination) boiler produces its central heating and all its hot water from just one unit. These are a very popular space saving boiler fitted in over half of the homes in the uk. There is no need for other components with this boiler saving on installation costs, time and money. Due to the nature of how this boiler works there is no need for expensiver pumps to increase your hot water pressure, the boiler converts a “cold mains feed” into a “hot mains feed” instantaniously.

There are five different types of combi boilers

Believe it or not there are five ‘varieties’ of combi boilers offered by boiler suppliers in the U.K., so it’s worth thinking through what’s right for you before diving straight in.

  • A combi (instantaneous) gas boiler is the most commonly used form of combi boiler and as the name implies instantaneously heats incoming cold water from the mains to supply your taps, showers, baths and other hot water requirements.
  • A combi (instantaneous condensing) boiler operates as an ‘instantaneous’ boiler but at somewhat higher efficiencies than the standard combi boiler.
  • A combi (storage) boiler is a variant of the instantaneous combi boiler type referred to above and is designed to give you better hot water performance through the internal storage of heated water. The stored water also can give you better initial water supply from cold water mains on first turning on the tap. Once the stored heat has been used, this boiler will tend to operate as an ‘instantaneous’ type. Dependent upon the make and model, the improvement in heated water delivery will depend upon the size of water store, and this can vary widely.
  • A combi (storage condensing) boiler operates in principle as a ‘storage’ type but at higher efficiencies.
  • Combined Primary Storage Unit (CPSU) is a special category of storage combi which will incorporate a very large water store allowing a high water flow rate to taps and other draw off points and to quickly heat radiators before the water store is used.
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