Jeff Barsalou
Buying new energy-efficient windows is an exciting time. Whether you’re doing it to reduce the energy bill, enjoy comfortable, consistent home temperature, or hear less noise from the outdoors, the benefits are worth the upgrade. Simply buying the windows, however, is not enough on its own. Correctly installing them is the only way to experience the full benefits.
Reducing the energy consumed for heating and cooling is the number one reason for choosing higher efficiency windows. The payback period is between seven and twenty years. This depends on the building, lesser performing alternative, and the new windows being installed.
Another benefit of new windows is to minimize road and neighbor noise in the house. Sound transmission is measured either with the Sound Transmission Class (STC) rating or the Outdoor/Indoor Sound Transmission Class (OITC). Either way, the higher the number, the better the sound-blocking capabilities.
Another thing to consider is window performance levels. Besides the various insulation levels of double- and triple-pane units, the best windows also pass performance criteria discovered by independent testing.
Good windows improve the water resistance of your home’s building envelope and can enhance the appearance of the entire house, too. LoE coatings on window glass reduce the energy lost by radiation, and argon gas between panes improves the overall R-value of the whole glazing unit.
Divided lites and grilles are a significant visual window feature, especially with older homes. They can add a lot, but may not be the desired look you want when replacing. Newer window styles trend towards more glass, sowhen replacing units itis a great time to remove or omit features such as divided lites or grilles.
How you plan to install your windows can be a powerful part performance and it is crucial that it is done with care. Even if you know the steps and technical details like the back of your hand, always review a detailed installation procedure from the manufacturer, which should include the following points.Use caulking to seal the window mounting flange to the exterior surface of the building wrap if it’s visible. This caulking is part of the seal you need to create, but you still need exterior flashing.
- Use low-expansion spray foam around windows. This particular type of foam helps ensure window frames don’t bow inwards, allowing operable windows to be opened and closed easily.
- Install temporary props to support window and door jambs against bowing inward. These props are in addition to the application of gentle foam. Wooden props cut to fit opposite sides of the window jamb ensure that foam expansion poses no problem.
- Always use flashing. Never rely only on the window installation flange for waterproofing a window installation. (Flanges are for anchoring only, and while they keep out some water, flanges alone are not enough for a reliably dry installation.) Instead, use self-sticking or metal flashing. Install the flashing over the top of a window so it overlaps the flashing on the sides. This side flashing must overlap the bottom flashing, so the whole installation sheds water.
- Install a plastic drainage pan. This pan is cheap insurance against window leakage. Drainage pans are sloped plastic devices made to sit underneath a window unit in the rough frame. If leaks get past the windows, the sloped drainage pan directs the water out of the building harmlessly.
- Lap any building wrap over window openings, so all the layers shed water.
- Install support shims at all four corners of a window frame and every twelve inches along the bottom. Always use shims in pairs to provide full support under the window frame. They can be plastic or wood that won’t fall apart if shims get wet.
New windows are a significant investment and you should source professionals to help make wise purchasing and installation decisions.
Jeff Barsalou is the Marketing Manager and U.S. Business Development Manager for Kohltech Windows & Entrance Systems. Kohltech recently celebrated 40 years of vinyl window manufacturing.
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