Room heaters within a house extension

Where the house that is being extended does not already have central heating, it is a good idea to consider the installation of a central heating system, with a condensing boiler, as part of the extension project.

However, if this is not appropriate or affordable the extension may be equipped instead with one or more fixed individual room heaters.

There are several types of room heaters, which run on gas, electricity or solid fuel.4 Better types of room heaters are equipped with time and temperature controls. Unless it is electric or has a balanced flue, a room heater must have a supply of combustion air brought into the room from outside.

Natural gas heaters include wall-mounted models as well as traditional open hearth and fireplace installations. Wall-mounted heaters provide more flexibility of siting within the room, depending on the type of flue; some models must be fitted on an external wall, but others can be fitted on an internal wall with the flue routed to an external wall. The efficiencies of natural gas heaters vary. Some decorative ‘open-basket’ focal-point heaters have efficiencies as low as 20 per cent, but the efficiencies of closed radiant convector heaters (including some with the popular coal effect) can be 75 per cent or more.

Electric room heaters such as panel heaters, convector heaters and radiant heaters are 100 per cent efficient (all the energy in the electricity is turned into heat in the room) but they are very expensive to run because they use on-peak electricity, and the associated carbon dioxide emissions are high. Wherever possible, these heaters should be equipped with programmers or time-clocks, and thermostatic controls.

Solid fuel room heaters include open and closed solid fuel fires with and without back boilers (to provide hot water), and free-standing solid fuel stoves. Closed room heaters (with glass doors) and stoves are much more efficient than open fires. In most urban areas only smokeless fuels may be used.

Using a gas-fired room heater to heat an extension will involve much lower carbon dioxide emissions than using an electric heater. However, using a wood-burning stove (burning wood chips, wood pellets or logs) involves little or no carbon dioxide emissions.