Sustainability, energy conservation, wise use of natural resources, recycling, save the earth—these are all related ideas, and timely, given rapid development in much of the world and the fact of global warming. “Green design” is the latest form of the idea, especially as it relates to manufactured products and buildings. Buildings, including houses, use more energy than transportation or industry, so any improvement in this sector has a far-reaching effect.
If you are a homeowner or a building manager, you can use green design to reduce your operating costs, while benefiting the planet. The national design program called LEED is the most comprehensive way to go about it, and there are programs like EarthCraft and Energy Star. They all analyze a wide range of materials and methods, and they use a point scoring system to show how a project is better than standard practice. There is no one answer, but many choices which you can combine in various ways. For new construction or remodeling, here are five features that are frequently used.
Rain Water Collection
Instead of piping rain water from the roof to a storm drain, or spilling it on the ground, collect it in a rain barrel or cistern. You can use it for washing, watering plants, filling a garden pool, or whatever else you can think of. Plastic rain barrels are available in various sizes and prices, or you can make your own for a few dollars. A cistern is larger, and may be specially built, either in the ground or elevated to provide gravity flow. If you want to use the water for drinking, you will need a way to filter it and test the purity.
Solar Collector Panels
These are typically mounted on the roof, facing south for maximum solar gain, at an angle determined by the type of panel and the location of the building. The technology is still developing, and there are many types of solar panels and storage systems. Those used to generate electricity are still expensive in relation to other generators. They are used for special low-demand purposes, or in places like Germany where government subsidy balances the high initial cost. Solar panels are most cost-effective when used to provide domestic hot water. And they work best in places with lots of sunshine, like the American Southwest, not so well in cloudy climates.
High-Efficiency HVAC
Heating, ventilating and air conditioning, or HVAC for short, has advanced in the past few years. The engineering of HVAC systems, electronic controls like thermostats, and the quality of equipment and installation have all improved greatly. Efficiency, which measures how much of the energy going in accomplishes the task, is rated in SEER, and the ratings rise year after year. By replacing old HVAC equipment, and by overhauling existing systems, you can reduce energy use, whether electric or oil, save money, and improve comfort at the same time. The payback period for such an improvement can be surprisingly short—a few years, if the old system is very inefficient.
Insulate and Seal Gaps
In new construction, one of the easiest and cheapest ways to improve the energy performance of a building is to insulate properly, and to seal all gaps and penetrations to prevent air leaks. Insulation comes in many types, some of which are greener than others. Blown cellulose, for example, is recycled newsprint. The key with insulation is to put the right amount into floor, wall and roof, as determined by the building code or engineer, and install it as the manufacturer recommends. Where doors, windows, vents, and other things penetrate, use caulk and other sealants. In remodeling, the task is not so easy, but the benefits are just as great. Sprayed foam insulation is sometimes put in existing cavities to both seal and insulate.
Use Quality Windows
In a new house, windows are a significant part of the budget, and builders are tempted to use an inexpensive product. For long-term use and savings, though, it pays to use windows that are made with quality wood and metal, insulating glass with low E, and flanges and hardware that ensure a tight fit. In an old house, you can replace the windows, and get the same benefit. In both cases, you can add awnings or other exterior shade devices to reduce solar heat gain. Or you can add glass area to increase passive solar absorption in winter—think of a greenhouse. Natural sunlight can reduce the need for electric light, and natural ventilation—open a window—can reduce the energy used to heat and cool. Whatever way you look at them, windows are green, if you choose wisely.