When it comes to replacement windows, you might find wood an attractive option because of the classic, rich look and feel. However, with that classic look and feel comes heavy maintenance. Wood windows are initially expensive and need to be frequently stained and sealed to keep from rotting, swelling, or warping. Wood’s susceptibility to the elements doesn’t make it the most energy efficient choice, which is why many homeowners concerned with home energy, will opt for vinyl windows.
Milwaukee area winters can be intense, and it’s important to have windows and home exteriors that can resist heat loss, keeping the heat inside your home rather than escaping out. This is what U-value measures. When looking at U-value ratings, the lower the rating, the less heat escapes the home. .3 or lower is the minimum rating required for a window to be considered “energy efficient”, although the Energy Star program requires a .27 or lower U value for our Northern Zone. Vinyl has excellent natural thermal performance, and vinyl windows can have U value ratings as low as .12 in triple pane glass, or .24 in double pane glass. Wood windows, on the other hand, can have U-values up to .5 or even higher for your old existing windows, especially if worn down from water damage or age. Even new wood windows generally do not meet the Energy Star U value requirement for U value, and those that do, do so by using technology more appropriate for warmer climates that can result in very dark glass, or even more condensation.
On the other hand, solar heat gain coefficient (or SHGC) is useful when summer comes in as well as winter. SHGC measures the window’s ability to keep heat out of the home, and should be balanced due to the fact that we want to keep heat out in the summer, but allow it in during the winter. The lower the rating, the less solar heat it conducts through the window. However, much like U-value, the performance of wood windows is often deteriorated due to prolonged exposure to the elements. As wood windows warp or swell, it’s easier for heat to get in. Energy Star rated vinyl windows can have SHGC ratings as low as .15, however in a cold climate like ours, we really want to see this rating around .20 or higher (up to .30+).
Air infiltration, or air leakage, is very important. This measures simply how much air passes through the window, whether escaping out or getting in. The goal, of course, is to have this as low as possible. This can be measured in CFM, or cubic feet of air per minute. The worst possible air filtration rating that can still be sold as certified is .30. At Homesealed Exteriors, many of the vinyl windows we offer have an air leakage rating of .01, the lowest possible rating, because a rating of 0 can’t be measured.
Design Pressure is something that’s talked about less, but it’s just as essential. Design pressure measures the amount of pressure from wind that a window can handle. Here, vinyl is a clear winner. While wood is heavier, it’s also much more susceptible to water damage, which can make it structurally weaker, eventually sagging and even breaking under the weight of pressure from static snow or other elements. Vinyl, on the other hand, is naturally flexible and sturdy, making it more durable and able to better withstand pressure. While vinyl itself can be pliable, the chambered structure of a quality vinyl window extrusion such as Okna will provide unparalleled strength, with DP ratings as high as 80, which is equivalent to a wind load over 200 mph! You may say, “Hey, I live in Wisconsin, not a hurricane zone!”, and that would be true. That said, the ability to withstand these high wind speeds speaks volumes about the strength of the window, and how long you can expect it to last.
But what does all this mean for your home? Well, the better your windows resist air infiltration, heat loss, and balance solar heat, and the better they stand up to the elements, the less you’ll have to use your heating and cooling to keep your home comfortable. This will help you to conserve energy, as well as save money on your heating and cooling bills. For more information about how vinyl windows can benefit your home, contact Homesealed Exteriors today.