The Many Benefits of New Windows
Windows are a controversial topic in the green building world. Most homeowners assume that their windows are the biggest drain on heating and cooling energy efficiency in their home, and the biggest gains in energy efficiency can be made by replacing old windows. Much of this assumption is driven by the marketing departments of window manufacturers, who for years advertised “guaranteed 50% energy savings” and similar claims – some of which have been banned by the FTC because they were found to be exaggerated and without scientific merit. Within the home performance sphere, window replacement is often shrugged off as a poor investment and one of the least important energy efficiency improvements. While it is true that window replacement is typically less cost effective than other home performance improvement measures, windows do save energy – and the more efficient the home is in terms of insulation and mechanical equipment, the more of a difference window replacement makes. Additionally, window replacement provides many benefits that improve the value and livability of your home:
- Sound: Especially in urban areas, it can be tough to find calm inside a home when noises from outside penetrate inside. The weakest point where sound transmits into the home is usually the single pane windows facing the street. Nuisance sound can range from traffic, landscape and construction work, and passing pedestrians, to the howl of rapid transit trains. Vibrations, especially from car and train traffic, can rattle old single pane windows. Windows are rated for sound control by the Sound Transmission Coefficient (STC). Sound transmission is halved by each 10-point increase in STC. An old single pane window would typically have an STC of 18. Upgrading to a typical dual pane window with an STC of 27 will yield almost a 50% reduction in noise transmission through the window.
- Air Leakage: While the attic and crawl space are usually the locations to achieve the biggest reduction in the draftiness of a home, without addressing the windows, it can be impossible to achieve the recommended air exchange level of 0.35 Air Changes Per Hour. If air quality and controlled ventilation are goals for your project, window installation will often be an important component to ensure a successful project.
- Resale value: Windows are one of the first things a potential buyer notices when considering a home purchase. Many people perceive that upgraded windows are a sign that a home has been well-maintained. In addition, windows are also one of the most expensive building components in a home, so many home buyers think of new windows as a deferred cost of ownership. Window replacement carries such a strong resale value that when Bankrate published a list of the “Top Ten Remodeling Projects for Resale” based on a study by Remodeling magazine, different categories of window replacement accounted for four of the ten projects on the list. Across the various categories and geographic markets in the study, window replacement recouped an average of 83% of the project investment at resale, and in markets like San Francisco and Los Angeles, the value added by the window replacement actually exceeded the cost of the project!
- Appearance: Aesthetics are largely subjective, and many people (including me!) love the look of classic wood windows. However, as these wood windows age, they require a lot of maintenance to remain beautiful and structurally sound. And almost universally, the aluminum windows installed in most homes built between the 1950s and 1970s are almost universally disdained for the way they look. In most cases, replacing windows will improve the look of your home from both inside and outside.
- Fire Safety: Building Code requirements regarding egress from a building in case of a fire are both stricter and more universally enforced than they have been in the past. Many bedrooms have double hung windows which often don’t have large enough openings to meet fire code egress requirements – meaning that some people, particularly children and senior citizens, may not be able to escape in case of a fire. Replacing these double hung windows with casement or awning windows, which allow the entire window area to open, typically bring the windows into code compliance. Also, many towns require tempered glass to reduce the likelihood of the window shattering in a fire. This is especially common in the Western U.S. where forest fires are more common and widespread. Meeting egress fire code may be required when undertaking a large remodeling project or selling a home, and could save lives in the event of a fire.
- Comfort: Our bodies’ thermal comfort is primarily dictated by the temperature and humidity of the surfaces around us. With an R-value of less than 1, single pane glass transmits heat many times faster than almost any other surface in a home, and sitting next to a window on a cold day can chill an occupant even when the thermostat is set to a comfortable temperature. In addition, single pane glass often gets colder than dew point, causing condensation to collect on the inside of the window, decreasing comfort even more and contributing to mold and even peeling paint and rot if the moisture is not wiped up.
The bottom line is that in the vast majority of cases, replacing windows will never pay for itself in energy savings. However, windows provide many benefits beyond energy savings, and often do pay for themselves when the home is sold. If you are considering investing in windows, consider all the benefits, not just energy, when making your decision.
Copyright September 2014 by Advanced Home Energy
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