Sustainability is expressed as meeting present environmental, social, and economic needs without compromising these factors for future generations A practice cannot be said to be 'sustainable for X years/generations.' The use of any span of time disqualifies the activity. Sustainability is for perpetuity.
Sustainability also means greater efficiency in resource use, ultimately giving benefits to economic growth and overcoming poverty, as well as health and quality of life.
Sustainable design and sustainable development are critical factors to sustainable living. Sustainable design encompasses the development of appropriate technology, which is a staple of sustainable living practices. Sustainable development in turn is the use of these technologies in infrastructure. Sustainable architecture (see Green building) and agriculture are the most common examples of this practice.
Solar thermal energy
. The sun is the source of the vast majority of the energy we use on earth. Most of the energy we use has undergone various transformations before it is finally utilized, but it is also possible to tap this source of solar energy as it arrives on the earth’s surface.
There are many applications for the direct use of solar thermal energy, space heating and cooling, water heating, crop drying and solar cooking. It is a technology which is well understood and widely used in many countries throughout the world. Most solar thermal technologies have been in existence in one form or another for centuries and have a well-established manufacturing base in most sun-rich developed countries.
The most common use for solar thermal technology is for domestic water heating. Hundreds of thousands of domestic hot water systems are in use throughout the world, especially in areas such as the Mediterranean and Australia where there is high solar insolation (the total energy per unit area received from the sun). As world oil prices vary, it is a technology which is rapidly gaining acceptance as an energy saving measure in both domestic and commercial water heating applications. Presently, domestic water heaters are usually only found amongst wealthier sections of the community in developing countries.
A rainwater catchment system set up by Isla Urbana with the Huicholes in Mexico.