by Chris Woodford. Last updated: November 6, 2013.
Most of us take a pride in where we live and look after our homes. Earth is our home too, but you'd never know it from the way we treat it: the planet is under ever-increasing pressure from the things we do. Each day, there are more people trying to survive on the world's limited resources—by turning farmland into factories, burning down forests, pumping out oil, and belching pollution into the air. If you care about the planet, there are lots of small things you can do that will make a small difference: you can recycle your trash or swap your gas guzzler for an electric car. But if you want to make a really big difference, you have to make a much bigger change in the way you live. One way you can do this is to swap your cold and drafty, energy-guzzling house for a lean, green eco-home powered by renewable energy. Let's take a closer look at eco-homes and how they work!
Photo: This typical eco-home in Westminster, Colorado is built from wood (a sustainable, local material), has huge windows to absorb sunlight, and makes power with solar cells on the roof. Photo by John Avenson courtesy of US Department of Energy/National Renewable Energy Laboratory (DOE/NREL).
Where to build eco-homes
If you're trying to show a bit of respect for the planet, the last thing you want to do is build a big, brash, shiny new home. Instead, you want your eco-home to blend into its surroundings the way a moth camouflages itself against the bark of a tree. Some of the most striking eco-homes are earth-sheltered houses. Instead of being made of brick or concrete and standing proud above ground, they squat modestly against earth banks or they're constructed substantially underground. That not only helps them blend unobtrusively into the landscape, it also provides warmth and shelter, reduces the need for heating, and saves energy.
Photo: This earth-sheltered in Minneapolis, Minnesota is set into the ground. Photo by Pamm McFadden courtesy of US Department of Energy/National Renewable Energy Laboratory (DOE/NREL).
Eco-materials for eco-homes
Building a house uses a huge quantity of raw materials. From the
bricks that make up the walls and the timbers that support the floors
to the electricity cables and pipes
that run in between them, a house is
consuming a significant amount of Earth's raw materials. One of the
most effective ways to reduce the environmental
impact of a new home is
to use recycled materials instead of
brand new ones. It's relatively
easy to find recycled timbers to make floors, for example, and recycled
glass made from old glass bottles is also fairly easy to come by. You
might be surprised just how many recycled products there are and how
much fun you can have trying to place them in your home! Did you know
that you can get chairs made out of recycled bicycles,
from recycled office paper, and kitchen crockery woven from recycled
telephone cables? You can buy a lot of nearly new things from eBay and
save a fortune, as well as help to save the planet. Most places have
local community recycling schemes and salvage yards nearby. It costs
you nothing to explore these places and you might be surprised by what
It's seldom possible to make a new home from entirely recycled materials. Where you need to use new materials, you can try to source them locally. That will help reduce the cost of transporting materials to the construction site (and the energy wasted in the process), but it also helps a new home to blend in with the local architecture. If you use local artisans and workers to build your home, you're also helping to put money into the local community and the local economy. Thinking globally and acting locally is an important part of saving the planet.
Saving energy in an eco-home
Most homes consume colossal amounts of energy,
mainly for heating in
the winter, air-conditioning in the summer, and supplying hot water for
our baths and showers. We use smaller (but still significant) amounts
powering domestic appliances such as clothes washing
televisions, and computers. (Generally speaking,
appliances that get hot when you use them are the most inefficient:
they waste quite a bit of the power they take onboard making that heat
from electricity with heating elements.)
Photo: You can reduce the energy losses from a home by squirting the walls full of foam insulation, which you then simply cut and smooth to fit. This home is insulated with Icynene, a plastic insulation material similar to that used in pillows and mattresses. Photo by Paul Norton courtesy of US Department of Energy/National Renewable Energy Laboratory (DOE/NREL).
Eco-homes try to tackle the problem of energy use in two different ways. First, they are designed so they need less heating and air-conditioning. Many eco-homes have large areas of glass on walls that face the sun for much of the day. By absorbing as much sunlight and heat as possible (a technique called passive solar gain, eco-homes can reduce the need for electric, oil, or gas heating. Most eco-homes also have very large amounts of insulation (dense, air-filled padding stuffed into the walls and ceiling spaces) to reduce heat losses to the atmosphere. While many traditional buildings (especially old-fashioned offices) need air-conditioning in the summer months, eco-homes are generally designed to use natural ventilation. As well as having opening windows, some of them are designed in an egg or spiral shape so that air naturally sucks in through the bottom and spirals up and out through the top to keep the building cool.
Photo: Huge glass windows, oriented to face the sun, heat this home effectively through passive solar gain. Photo by Chris Gunn courtesy of US Department of Energy/National Renewable Energy Laboratory (DOE/NREL).
No matter how well-designed and insulated, an eco-home still needs energy to power appliances. But there's absolutely no reason why this power has to be transported huge distances from an enormous power plant, wasting vast amounts of energy in the process. (Did you know that two thirds of the energy a power plant makes is lost either in the plant itself or on the journey to your home? What a waste!) Every building in the world has the potential to make a significant proportion of its own power. In sunny climates, solar panels on the roof can be used to heat water (known as passive solar or solar thermal energy) or to generate electricity (known as active solar or solar electric energy). In windy countries, how about a small micro-wind turbine mounted on the roof or positioned in a corner of the garden? Spinning away silently as the breeze blows past, it could be cutting your energy bills and helping to save the planet. Most eco-homes come to an arrangement with the local power companies so that any extra energy they generate beyond what they actually use can be sold back to the power grid, earning them money!
Photo: The electricity meter in this eco-home is designed to run either forward or backward. When the solar panels on the roof are generating more electricity than the house needs, the extra feeds into the local grid and helps power other people's homes. It can be very satisfying to watch your electricity meter running in reverse! Photo by John Avenson courtesy of US Department of Energy/National Renewable Energy Laboratory (DOE/NREL).
Saving water in eco-homes
Most of the world's water is used for such things as agriculture and industry, but our homes also use a great deal as well. Every time you flush the toilet, brush your teeth, or fill the kettle to make a cup of coffee, you're using water—but you also using energy, because it takes energy to make water clean and pure enough to drink. We can all reduce the water that we use in simple ways like switching the tap off when we brush our teeth or buying "intelligent" washing machines that get our clothes cleaner with less water. These things all make a difference. But if you're building an eco home, you'll want to go one step further by installing a greywater system. This is effectively a large tank in your house or your garden that stores some of the water you've used for reuse before it returns to the sewage system. Water from your washing machine and shower is probably still clean when you've used it, so instead of draining into the ground, it flows into the greywater storage tank instead. This, in turn, can flush your toilet and water your garden. (Think about it: why flush your toilet with crystal clear drinking water that's been super-cleaned and purified? It's just absurd!)
Talking of toilets, they waste a huge volume of water. In many countries there are now laws requiring new toilets to have a dull-flush system, which lets people choose either a small or a large amount of water when flushing. Again, some eco-homes go one stage further by having composting toilets. These do away with water altogether. Instead of flushing into the sewage system, the waste drops through into a container underneath the house where it is safely turned into compost (an earth-like material) that can be used on the garden to help grow your plants. Composting toilets might not sound very nice, but they don't smell and they really work! And there's nothing better for the environment than "closing the loop": turning your waste back into something useful.