These provide heat for your radiators and domestic hot water on demand. Hot tap water comes directly from the mains and is heated as it’s used, so there’s no need for a separate hot water storage cylinder or cold water feed cistern.
However, there is a small time lag between turning on the tap and getting hot water, and the flow rate is limited by how quickly the boiler is able to heat up the water.
The advantage is that they require less space than heat-only boilers (because there is no storage cylinder), this avoids heating water that is not used immediately. On the down side, the flow rate limits how much water you can use at one time; e.g. no filling the kitchen sink while running a bath.
You could also miss using the (wasted) heat from your hot water cylinder in your airing cupboard, however we can always install a small radiator within the airing cupboard.
Heat only boilers provide heat for radiators directly, but they need to be connected to a separate hot water storage system including a hot water cylinder, cold water cistern and in some cases an additional expansion cistern.
These arrangements take up more space than a combi system, but are able to provide hot water to several sources at once and are more suitable for larger houses.
With a new high recovery unvented hot water cylinders are very quick to heat up and are very well insulated so the heat loss is very minimal
With older systems, unless a cylinder is very well insulated, it usually loses heat into its surroundings, thereby wasting energy, and with slow reheat times the amount of hot water you can use is limited by the size of your cylinder.
For instance you may run a bath, then need to wait for the boiler to heat up the water in the cylinder again before you can run another.
The system boiler, often listed as a ‘sealed system’, provides central heating and hot water via a storage cylinder, meaning that, unlike with a regular boiler, there’s no need for separate water tanks in the loft of your house.
These models are a great choice for those who have limited space in their loft, or for those living with a large family who wish to use hot water from multiple sources at once.
System boilers do not require a feed & expansion tank, freeing up valuable space in your loft and meaning that we can offer a more efficient and cost-saving installation process.
With over 20 years experience installing and maintaining heating systems, we will do all the calculations to provide you with a solution that suits both your property and your budget.
We are an independent installation company, which means we can choose the best products to suit your requirements and we are experienced in installing a wide range of heating systems.