PSHD (Passive Solar Home Design) is the term used to describe the process that takes advantage of a building’s site, climate and materials to minimize energy usage. A passive solar home gets at least part of its heating, cooling and lighting energy from the sun, and windows—and their ability to either retain or lose heat—play a large role in regulating that energy.
The efficiency of existing windows can be dramatically improved by utilizing weatherstripping or caulking, and by adding storm windows or window treatments and coverings. In some instances, the better option is to replace older, less efficient windows with new ones that are better-designed for energy-saving purposes. They quickly pay for themselves in reduced utility costs.
Before installing new windows, it’s important to determine the type that will work best in your home’s configuration. Consider that south-facing windows will collect the most solar heat. This is advantageous in the winter months, but less so in summer months, particularly in warmer climates. In those areas, overhangs, glazing, or other shading devices will help to prevent excessive heat gain. In colder climates, owners will welcome the additional warmth that southern-facing windows can absorb.
Windows on east- and west-facing sides of your home admit less sunlight. It is more difficult to control the heat and light that come through them; ideally, they should have a low solar heat gain coefficient (SHGC). This is a scale that determines the fraction of solar radiation admitted through a window or shading of some type. You can learn more about this scale at www.energy.gov.
Northern-facing windows collect no solar heat and generally are used only for lighting. They can’t be counted on to provide sustained warmth.
Consider, too, the type of window operating system you want to install, since different styles have different air leakage rates. Fixed panes do not open at all, making these generally airtight, but no ventilation is available, either, which can reduce their appeal.
Single- and double-hung windows have two separate panes of glass. In single-hung windows, only the lower half of the window opens, sliding upward. In double-hung windows, both halves are moveable. Both types have a much higher air leakage factor, since they don’t seal as efficiently as other styles.
Similarly, single- and double-sliding windows feature glass which slides horizontally, and they, too, have higher air leakage.
Casement windows are hinged at the sides and open outward. Both these and awning windows, which are hinged at the top, are more airtight since the sash closes by pressing against the frame.
Naturally, your selection is going to come down to the style that looks best on your home but, armed with this information, you can make a choice that balances aesthetics with energy-efficiency.
Even the most energy-saving windows must be installed correctly to ensure their efficiency. The craftsmen at Handyman Matters are always available to assist with this important home upkeep task. Call 1(800)FIX-MY-HOME to locate the office nearest you.