Condensing Combi Boilers

Combination boilers provide heat and domestic hot water on demand.

Typically they do not store hot water, although some do have a small storage capacity.

Water comes directly from the mains and is heated as it is used, so there is no need for separate hot water storage cylinder or cold water feed cisterns.

They can provide a continuous flow of hot water, but at a lower rate than a conventional hot water storage system. This means they are less suitable for houses where there are simultaneous demands on the hot water, such as multiple bathrooms or showers.

The advantage is that they require less space and avoid heating water that is not used immediately.

The disadvantage is that you must learn to use the hot water from one source at a time – no filling the kitchen sink while running a bath for instance. You might also miss using the hot water cylinder in your airing cupboard.

Combination boilers are chosen for their hot water heat output, which is usually greater than is needed for their central heating output.

For this reason the burners will modulate, reducing their firing rate to match the lower heat output requirements when you are just using the heating.