A window is a window is a window. Right?
Wrong. There’s a lot to consider when buying windows – and it’s more than just aesthetics that comes into play. Of course, you want your windows to look good, but more importantly, you want them to keep out winter’s cold and summer’s heat.
According to the U.S. Department of Energy, heat loss and gain through windows are responsible for 25 to 30 percent of residential heating and cooling energy use. One way to combat those statistics is to look for the star – as in the ENERGY STAR label. On it, you’ll find information about that particular product’s U-factor and solar heat gain coefficient as well as its visible transmission of sunlight, condensation resistance and air leakage. Those first two are energy performance ratings that can give you a good idea of how efficient your new windows will be but only if you understand what they mean.
According to the energy department, U-factor is the rate at which a window, door or skylight conducts non-solar heat flow. The lower the U-factor, the more energy-efficient the window, door, or skylight.
Solar heat gain coefficient [SHGC] is the fraction of solar radiation admitted through a window, door or skylight – either transmitted directly or absorbed – and subsequently released as heat inside a home. How your windows face the world and how exposed they are to sun and shade plays a key role in determining how high or low a particular window’s rating should be. A product with a high SHGC rating is more effective at collecting solar heat during the winter. Likewise, a product with a low SHGC rating is more effective at reducing cooling loads during the summer.
It stands to reason that large windows without significant shade from trees, overhangs or awnings are more likely to let in all the benefits of sunshine and its hazards, including UV rays that can fade carpets, floors and pictures. South, east, north, west – yes, you have to consider location when picking windows that fit your needs best.
In addition to understanding performance ratings, educated consumers are wise to gain a basic knowledge of glasses and glazing.
Window glass is available in single, double or triple panes, but in St. Louis, single-pane glass really is not an option. Double- and triple-pane windows up the energy-efficiency quotient through the use of thermally efficient gas fills between the panes. Gas fills combined with low-emittance [low-e] glass results in a window that maintains a low U-factor while reducing SHGC even as it allows in beautiful sunshine to fill the room.
Now, that you understand the basics, it’s time to call in the pros.
Installing windows is part art, part science and, for the sake of your bank account, is best left to professionals.
The window experts at Dalco Home Remodeling can help you choose the right windows for your home and make sure that their installation is a worry-free process that will help you save energy and dollars from day one.