Installing double-glazing can save you up to 20% of your fuel bill. It also reduces noise coming in from outside. Secondary double glazing – fitted in addition to your existing windows, is cheaper, but less effective. This is because it is the air gap that provides the insulation, not the extra layer of glass, and this is more effective in a double glazing unit.

Limecrete is an environmentaly friendly alternative to concrete, which is lightweight, breathable and self-insulating.

As those of you who saw it being used to build the foundations on one of Kevin McCloud's Grand Designs programmes on Channel 4 will remember, it is advisable to bring in experienced layers to do the job.

Aircrete bricks look like breeze blocks but are only a third of the weight, thus saving on raw materials. They are made from a substantial proportion of recycled materials, which in some cases includes coal-fired power station waste. They have excellent thermal insulation properties thanks to millions of tiny air holes. Building is quicker because the blocks are lighter. They can be used externally, internally and for foundations. They are resistant to water and rot and are extremely fire resistant.

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