Throughout the history of mankind, buildings and homes have been constructed with much consideration for environmental conditions, making the best use of the sun for light and warmth and the wind for cooling. Although these measures were intended initially for survival, they are the earliest measure of environmentally friendly solutions.
Today there are many technologies, products and systems which provide opportunities to minimise use, and thus cost, of energy used in buildings. Many of these solutions, such as solar panels, photovoltaic panels, ground and air source heating, are able to produce energy from a source we would never have considered in the past. They are almost able to conjure energy from nothing at all it seems.
The use of low impact materials, which are sustainably produced are healthier for the environment as well as a buildings occupants, and compliment the environmentally friendly energy solutions mentioned above.
Use of low impact materials -- that are healthier for the environment as well as the occupants in the building. E.g. use of materials that are non-toxic, produced in sustainable ways and are found locally, are made from recycled materials, or can be reused or recycled at the end of its lifespan, etc.
Use of energy and water efficient technologies -- that help to conserve energy and water use in the dwelling. For example, the use of motion sensor lighting, energy efficient air-conditioning, water saving devices, high performance insulations, ground or air source heating systems, solar panels for water heating and photo voltaic panels to generate electricity.