Most houses with access to mains services are heated by gas central heating or electric storage heaters and those further away from suburbia can import heating oil or liquid petroleum gas (LPG) to run similar systems.
Of course, if global warming is really upon us, we will have to get used to cooling buildings as well as heating them. This is nearly always done by electrically powered air-conditioning units, most of which contain gases that are harmful to the atmosphere when released.
But all of these, either directly or indirectly, rely on fossil fuels to generate their power, and the drive is on to find less damaging alternatives.
Of course, the first steps to reducing fossil fuel usage in the home is to insulate properly and stop up any draughts, install or upgrade double glazing and install newer, more efficient boilers and controllers. This will mean you use less fuel, regardless of the type of system you have.
The most common form of ‘green’ building heating at the moment is solar powered water heating using panels on the roof, though often it’s used to heat the water in the home, for washing etc, rather than to heat the home through a central heating system.
This is because the temperatures that these systems can reach in the British winter, just when you need the heat, simply aren’t high enough for a conventional radiator system.
They can assist the heating though, so that although you have to use other methods to heat the water to the required temperature, at least you aren’t starting from such a low initial temperature.
An ecologically sound alternative is to use a wood burner, either to heat a room directly, or to heat a back boiler that serves a heating system.
Although it might seem odd to promote burning wood as a ‘green’ heating solution, the theory is that as long as the crop that you burn is replaced by growing at least the same amount back again, the system is technically carbon neutral.
The fuel needn’t necessarily be wood as such. There are plenty of burners that will accept pretty much any combustible material, generally referred to as ‘biomass’.
These can be fast growing crops such as bamboo, willow and some types of reed. It could even be agricultural by-products such as grain husks or animal waste.
Newer multi-fuel burners can burn these fuels in a clean and efficient manner, so it really depends on what sources of fuel you have available to you.
None of the systems mentioned above can cool a building though, they are all about heating.
The best way to cool a building to use passive cooling, i.e. cooling that happens without requiring energy to make it work.
This is most likely to be through properly controlled ventilation that uses the properties of air currents to conduct heat away into the outside air, but it is only really possible in a house where this has been designed in from the start.
Ground Source Heat Pumps
However, one system that appears to present a win-win solution to heating and cooling is the ground source heat pump.
This consists of a long coiled pipe that is laid down under the frost line, in most parts of the UK about a metre, where the ground acts as a heat store and keeps the temperature at a fairly steady 11-12 degrees centigrade.
A pump passes fluid through the coils, which can be arranged horizontally if there is room, vertically if not, and takes this heat to a conventional radiator system.
Then in the summer, when it’s hotter outside, the system can be used to cool down the air inside the house, transferring the heat back to the ground.
The system works much better with underfloor heating, which requires far lower heat levels than conventional radiators.
It does take a fair amount of electricity to move the fluid through the system, but if you can find a reliable renewable source for that, such as a wind or water turbine, or photovoltaic cells, that will help all the more.
Of course, you need to be on ground that is soft enough to excavate, so it often cannot be used in remote mountainous regions where the topsoil layer isn’t deep enough.
In this case there is an alternative in air source heat pumps, although they are not such efficient heaters at cold temperatures, so any system should be thoroughly investigated before selecting it.
Many renovations and self-build projects are carried out by people who are unable to find properties built by commercial developers with this level of ecological commitment.
This trend is increasing and delivering a route to market for the systems that these people need, which in turn makes them cheaper.
Hopefully the trend will continue and in the future, commercial developers will embrace these systems too.