Some of the technologies and features on show

High performance energy efficiency

Most of the Open Door properties have been retro-fitted with energy saving or generating technologies, but one or two have been constructed with energy efficiency in mind, so that they are cheap to run as well as being environmentally friendly. Energy efficiency may not attract the attention of renewable energy installations, but will become increasingly important as we seek to reduce the cost of running our homes and buildings, and the fossil fuels that we now rely on become more scarce and expensive.

Photovoltaic panels

The panels have become the most popular micro-generation technology over the last two years, and will prove a good long-term investment. The panels convert light into electricity, which can be used in the home or exported and sold to the National Grid. They can be mounted on roofs or on the ground.

Biomass heating

This includes wood burning stoves and automatically fed wood pellet boilers. Modern stoves and boilers can be very efficient and because trees take in carbon dioxide during growth, wood is a carbon neutral fuel.

Rainwater harvesting

Preparing water to drinking standard is energy intensive, so harvesting rainwater to flush toilets and water gardens makes economic as well as environmental sense.

Wind turbines

One of the oldest ways of harnessing the power of nature - generates electricity from wind

Solar water heating

This technology concentrates the heat of the sun into tubes within a panel to heat water, usually for household water supply.

Air source heat pump

In simple terms this technology works on a similar principle to a fridge (but in reverse), taking air from outside, removing heat from it (even in cold weather there is some residual heat) and pumping the heat into the home.

Micro-hydro power

This technology, using the power of water as it travels downhill, was used to power the first Industrial Revolution. The force of the water, which can be fully or partially diverted to increase its speed, is used to turn a turbine and thus generate electricity. It is a more constant energy source than wind, but each scheme has to be specifically designed for its location

Ground source heat pumps

Ground source heat pumps use pipes which are buried in the garden to extract heat from the ground. This heat can then be used to heat radiators, underfloor or warm air heating systems and hot water in your home. A ground source heat pump circulates a mixture of water and antifreeze around a loop of pipe – called a ground loop – which is buried in your garden. Heat from the ground is absorbed into the fluid and then passes through a heat exchanger into the heat pump. The ground stays at a fairly constant temperature under the surface, so the heat pump can be used throughout the year – even in the middle of winter. The length of the ground loop depends on the size of your home and the amount of heat you need. Longer loops can draw more heat from the ground, but need more space to be buried in. If space is limited, a vertical borehole can be drilled instead.

Permaculture

Permaculture combines three key aspects:

1. an ethical framework

2. understandings of how nature works

3. a design approach

This unique combination is then used to support the creation of sustainable, agriculturally productive, non-polluting and healthy settlements. In many places this means adapting our existing settlements. In other cases it can mean starting from scratch. The word 'permaculture' comes from 'permanent agriculture' and 'permanent culture' - it is about living lightly on the planet, and making sure that we can sustain human activities for many generations to come, in harmony with nature. Permanence is not about everything staying the same. It's about stability, about deepening soils and cleaner water, thriving communities in self-reliant regions and biodiverse agriculture.