Solar Thermal - for heating your hot water.

Great product - gives you around 40 - 60% of your hot water in a typical year. Take advatage of the Renewable Heat Incentive and reduce your payback time to just a few years.

Solar PV - for generating electricity.

Has been around for a long time, but the cost put people off. The new feed in tariff makes them much more acceptable. The payback is now a quarter or less, so get some on your roof. Before long you will be generating electricity for your own home.

Ground source heat pumps

Really best for new build or major refurbishment projects. They really need underfloor heating throughout the house to work at their best.
Remember this basic rule - you need 4 times the floor area of the house for the outside pipes in the ground. Or a deep borehole (expensive).

Air source heat pumps

Not as efficient as the ground source, but still usefull when put with underfloor heating. They loose efficiency in really cold weather and if you push the output temperature above 40C. Very good if used with solar thermal for the house or swimming pool.

Biomass boilers

Generally this means wood pellet boilers. Very efficient, work just like your old boiler and should be considered when replacing oil or LPG boilers. Very low impact on environment and work with radiators or underfloor.

Log Stoves

Simply wonderful to look at. Take care to find the ones that are actually designed for high efficiency and not just for looks. Though the two do go together with some manufacturers. You can also get wood pellet stoves, which look great.

Rainwater harvesting

Simply makes sense to do when building a new house. Given the shortage of fresh drinking water in many parts of the south of the UK, why would you waste good water flushing the toilet? Always buy quality pumps and other equipment.

Insulation

This should really be at the top of the page. After all if you spend the money to heat a house, why let it all pour out quickly because of poor insulation. Add it everywhere you can.

Compact Flourescent Lamps - CFL

Real energy savers. Greatly improved from a couple of years ago and give much better life than old bulbs. The savings you will get means you simply replace ALL old bulbs NOW. Check out the ssavings example.

LED lamps

You do need to be careful with these. There are lots of claims of equivalence with various levels of halogen lamps. The definitive numbers are in this table - and the reasons. Their lifespan and very low running costs mean they pay for themselves very quickly.