Eco House Design

Sustainable materials still tend to be more expen­sive than their alternatives and skilled people are hard to find and come at a premium. So trim the design, not the build. Cutting costs at the end of the pro­ject can result in a building that is a compromise which satisfies no one.

Shape and Orientation

The shape, size, location, topography and surroundings of your plot will all influence what can and can’t be done. South-facing elevations and roof planes are great, and tall, thin windows on the south will introduce more light and heat to the back of a room. But south-facing win­dows can overheat the home in summer. Planting decid­uous trees in front of the window will let sunlight in during winter and provide dappled shade in summer.

Designing an eco home is not just about the building. It is also about how the building sits in its landscape. Minimise its impact and think about its surroundings. Permeable tarmac for the drive, for instance, will reduce run-off and put water back into the land. Trees, shrubs and ‘wild’ areas will increase biodiversity and interest.

If you’re using solar-heat gains you will need some masonry mass to hold the heat. A concrete slab with tile covering in front of a south-facing window will hold heat well, but there is not much benefit in putting that oppo­site north-facing windows. Put the mass where it will do some good and minimise cement use.

Materials

Think first of using recycled or salvaged materials: they have virtually zero embodied energy, are available locally and cost less than a new equivalent. Timber, roof slates, and even bricks are all readily available and the range of new goods from recycled materials is growing — from carpets to roof tiles.

As to structure, timber frame, especially sustainable timber, with sustainable insulation, has true eco creden­tials. The rules are: timber first, steel last, less cement and avoid PVCu.

Energy

Let’s be clear, the greatest environmental impact of a house is from the fossil fuels it burns for its energy. No amount of eco-certified bamboo flooring can compen­sate for the impact of an oil- or gas-guzzling house. Direct the budget to energy conservation first, energy generation second and everything else last.

Operation

Eco design is as much about living in an eco-friendly way as about the house itself. Minimising your energy use, providing space for recycling bins or clothes drying, and using grey water will all help to reduce your impact on the planet, and the impact of the people that come after you.

Cost

In the long term, a well-designed eco house will recover its extra expense in lower running costs. It will command a premium price and will be more attractive to the buyer than the estate home down the road. More than ever before, a sustainable home is a sound investment.

Read more about eco homes in the Green section

Eco Self-builds

• An Energy-efficient Contemporary Self-build
• A Low-impact Self-build by the Thames
• A Low Impact Eco House
• A European Green Home

Further Reading:

• The Code for Sustainable Homes
• How to Specify Your Eco Home
• How to Build a No-Heat Home
• A Guide to Green Technology