Types of Gas Boiler and their Prices


A conventional boiler is one which heats water using a single heat exchanger. Some of the water circulates through the radiators. The rest goes into the hot water cylinder in the airing cupboard and is connected to the hot tap in bathroom and kitchen.

A condensing boiler has a larger (or extra) heat exchanger, to extract heat from the steam which would otherwise escape through the flue. The steam condenses back into water, which is where the name comes from.

Condensing boilers are more efficient than ordinary boilers, but they cost 100-200 more.

In 2005, the government decided that all new gas boilers being installed had to be condensing boilers, unless there were special circumstances. This can be thought of as a way of reducing fuel bills or or a green tax, depending on your point of view.

There are two types of condensing boiler: regular and combination (COMBI). Regular condensing boilers use a cylinder - the hot tank in your airing cupboard. Combination condensing boilers give instant hot water but have no cylinder.


There is little online information on the price of an installed boiler, unless you search through blogs and similar sources. Each house is different, and you need to choose the right one for a particular situation.

You can easily find prices for uninstalled boilers; they can be bought for 600-800 including VAT.

If all you want is a new boiler to slot into the place of your old one, you can get a good idea of the price by multiplying the boiler price by about 4.

A boiler, installed in an average-sized house, with no complications, will usually set you back about 2500 -3200. The fitting usually takes about a day.

My gas engineer friends confirm that these prices are about right.

If you need new radiators installing you can double it. 5k is not unusual.

ND, habitat21

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