Windows are a major source of heat loss and gain, and therefore they're a key element in any environmentally-friendly design. Here are some key tips for designing environmentally-friendly windows.
- Choose the appropriate size of windows for your home's orientation and your climate. Large windows on the north side of the home will maximize natural heating. But large windows on the south side may cause heat loss.
- Wooden frames are attractive, provide good insulation and are eco-friendly if the lumber comes from a renewable source. But bear in mind that they can be expensive to buy, especially if custom-made, and require periodical maintenance to ensure the wood does not rot. They are also hard to seal because the wood swells and contracts with changes in temperature.
- PVC frames are durable, require little maintenance and provide good insulation, but they are made from non-renewable resources and their production is a source of pollution.
- Aluminum frames are lightweight and durable. But because aluminum is a good conductor of heat, they can become hot to the touch and also require some kind of insulation (a 'thermal break') or treatment to make them energy-efficient. In addition, the production of aluminum uses large amounts of energy.
- Make windows taller rather than wider. This will let more light in.
- Select appropriate glass for your climate. Some types of glass are absorbent, meaning that they allow heat into the house; others are reflective, meaning that they keep heat out.
- Consider double-glazing if you're living in a cold climate. This type of window can be expensive to install, but it can cut heat loss by as much as 50 percent. It can also help to block outside noise.
- In warm areas, consider fitting insect screens over windows so that you can leave windows open and let cooling breezes in.
- Louvres, either in the form of louvred glass panels or louvred shutters, are a useful feature for warm climates, allowing you to admit and direct cooling breezes.
Remember these tips if you're planning to upgrade your home's windows to make them more environmentally-friendly.
