Windows

Windows are an important consideration in any new building or remodel, as they can greatly impact energy use through heating and cooling. Both the type of window and where they are placed (and how many) can affect insulation. The more insulation a window provides, the lower your heating bill will be during the winter months. The first thing to look at in choosing the most appropriate window is the National Fenestration Research Council (NFRC) rating. This contains 4 numbers which all indicate a window’s ability to block heat or light. The important numbers for insulation are the U-Factor (range .20-1.20) and the Air Leakage. Lower numbers in these indicate less heat transfer and thus a more energy efficient window. The other energy consideration is whether you want your windows to provide passive solar heating. Double or triple paned windows can be treated with a low-e glaze in between its panes which will allow solar energy to flow in but not out, passively warming your interior. This is a boon during colder months but may provide too much heat during the summer. If the room is air-conditioned it may be better to use a high-e glaze, which prevents solar heating. Lastly, try to use wood or vinyl framing for your windows, both of which provide good insulation. If these can be locally bought and sustainably made, even better. If you have the option of choosing where your windows will go, try to install south facing windows with awnings. This will allow more direct sunlight during the winter when the sun comes in lower, while the awning will shield light in the hot summer months.