Solar thermal
The solar panels that heat up the hot water, work in tandem with the existing system.
Pros: Free hot water when the sun shines. £ 400 in grant form is available.
Cons: Suffers from multiple glazing factors: improves reports on doorsteppers offering to install the system yet at a skyrocketing price.
What you should know: Expect to pay £ 4,000 plus. You may need to get a new water tank, which will add £ 400 or more for a fee. You also need a roof facing 90 degrees south. Further information: Solar Trade Association (01908 442290; solar-trade.org.uk).
Photovoltaics
Other solar panels, this time using sunlight to generate electricity. Also present as special tiles, very useful if you plan on replacing the roof.
Pros: The renewable energy strategy yesterday floated the idea of a feedback tariff, similar to that currently used in Germany. This means that households are paid a premium for the excess electricity they generate and hopefully ensure more people take the technology.
Cons: It will cost you - it could be £ 20,000-plus.
What you should know: Grants are available up to £ 2,500. Again, you need a roof facing 90 degrees south. Further information: Renewable Energy Association (r-p-a.org.uk).
Wind turbine
Critics say they will not turn on hair dryers. Supporters say they misunderstand. We say: they are controversial.
Pros: If successful, it is the highest statement technology. As renewable energy, the price is cheap - prices start at £ 2,000 for a 1 kw turbine (the average home power requirement is 2.5 kw, assuming a stable wind speed of five meters per second). 