Boilers
Central heating boilers are often powered by gas and come in two main types.
A conventional boiler heats water which is stored in a hot water cylinder for use in the domestic system - the water from the taps, as well as heating the water which heats the radiators.
A combination boiler does not need a hot water tank as it makes hot water on demand. This means energy is not wasted keeping a tank hot.
Modern boilers of either type are usually condensing type which means that the heat which would have escaped in the exhaust gas from the boiler is recaptured, making them extra efficient. New boilers usually must be the condensing kind.
When choosing a boiler it is best to go for high efficiency A rated models. There is a guide to high efficiency boilers on the Energy Saving Trust website.
See the page on Grants for heating and insulation to see if you could get help with a new boiler.
Renewable Energy
Alternatively it is possible to have a boiler powered by biomass, which means fuel grown sustainably such as wood pellets, but in Lewisham these have to meet strict air quality rules.
Details of grants and much more information on these and the renewable energy options below is available at the Low Carbon Buildings Fund (external site).
See also the Grants for Renewable Energy page.
Energy from the sun and wind
Energy from the sun and wind are called renewable as they do not get used up.
Solar energy can be used to heat water in addition to your normal boiler, but check if your boiler is able to work with this system. It can also be used to make electricity from a photovoltaic cell, also known as pv.
Wind turbines convert the power of the wind into electricity but tend to work better in the countryside than city as the buildings interfere with the air currents.
Heat from the ground or the air
Ground source heat pumps take the heat out of the ground and use this to heat your home, air source heat pumps take heat from the outside air.