Many buildings are heated by one or more gas boilers, often distributing heat throughout the building via a system of radiators much like a domestic central heating system. Some may use other distribution systems such as warm air distribution, usually as part of a ventilation system (which may also include cooling), or underfloor heating.
Smaller buildings may have a single package boiler, essentially a domestic boiler, where the burner, heat exchanger, flue and other elements are all supplied as a single unit or package. Larger buildings may have a bank of multiple package boilers, or they may have one or more commercial boilers, where the boiler itself, the burner, the flue, and the condensing economiser are all supplied as separate elements and fitted together on site.
If you have a gas boiler for heating then this will often also be providing hot water for taps, showers etc. Generally, the hot water will come from a separate hot water cylinder that is heated by a coil heat exchanger fed from the boiler. If you have a package boiler then this could sometimes be a combination boiler, or combi, in which case the hot water will come straight from the boiler as and when required, with no need for a hot water cylinder.
If you do have a hot water cylinder, then it is important that this is well insulated to avoid wasting energy as the water cools down. Insulation jackets can be applied to existing hot water tanks but often the best performance will be achieved by fitting a new pre-insulated tank. If a tank already has some insulation, then you could still save more by adding further insulation. We recommend at least 80mm of fibreglass insulation jacket or 50mm of pre-sprayed polyurethane foam.
Oil and LPG boilers operate in the same way as gas boilers, with a similar set of options. The main differences are that the fuel needs to be stored on site, with deliveries arranged when necessary, and the fuel is typically more expensive than gas. Oil is also a significantly higher carbon fuel than mains gas and so leads to a higher carbon footprint than an equivalent gas heating system.
Oil and LPG boilers are generally only found in buildings where there is no nearby mains gas supply.
These are not common in the UK due to the big price difference between electricity and other heating fuels. Where they do exist, the hot water produced by the boiler is usually stored in an accumulator tank – a large hot water cylinder used for space heating rather than for hot water supply. This means the boiler can be operated with a variable electricity tariff, heating the accumulator during cheaper off-peak times of day.
This will help to keep operating costs down but is unlikely to make this an attractive option for space heating.
There are a number of technologies that use electricity to heat a room directly, either by heating the air in the room or by radiating energy into the room, or a mixture of both. These include...
University College London has replaced boilers with more efficient models and connected its room booking system with the heating control system to ensure rooms are only heated when they are in use.