Windows are an essential part of a Katahdin Cedar Log Home. They provide light and an opportunity to bring the beautiful setting outside into the home. As part of our complete package, Katahdin provides Andersen 400 Series windows, designed to provide insulation and protection from the elements, as well as classic good looks and an array of sizes and shapes.
Recently, the Energy Star program revised its classifications on windows, which are now “Qualified” as Energy Star compliant. (The previous standard was “Certified;” no relabeling is required on existing stock, but more stringent requirements are now in force.) The new standards increase the efficiency required for each of the four zones identified for window classification: a mostly heating zone (Northern), two heating and cooling zones (North- and South-Central) and a mostly cooling zone (Southern). Each label shows a map identifying the regions where the window meets the requirements.
This means that each window has a label (left) that indicates the results of approved testing by one of the National Fenestration Rating Council’s approved laboratories. The windows are tested on four specific performance ratings: U-Factor, Solar Heat Gain Coefficient, Visible Transmittance, and Air Leakage. Another rating for Condensation Resistance may also be included. These all are important characteristics of windows, and provide an easy way to assess each window based on its orientation in the home as well as its geographic location or climate zone.
U-Factor— In windows, the U-Factor is used to measure how well the windows prevent a loss of heat. The lower the number is— in a range of 0.15 to 1.20— the better the window performs in keeping heat in the house. The U-factor is particularly important in colder climates where heating takes place through a good portion of the year. U-Factor, which measures the rate of heat loss, differs from R-Factor, which measures the resistance to heat loss. The U-Factor is also affected by the airflow or convection around the window and the amount of radiated or reflected heat through the glass.
Solar Heat Gain Coefficient (SHGC)—This rating measures how much of the solar heat is blocked and is reflected in a number between 0 and 1. In the Southern states, the SHGC should be lower to keep as much of the sun’s warming effects out of the interior of the home. In cooler climates, a higher SHGC will allow the homeowner to harvest the passive solar heat created by the sunlight through the winter.
Visible Transmittance—This measures how much light passes through the window and is also a number between 0 and 1. The higher the Visible Transmittance, the more light will be allowed into the interior spaces. A lower VT number might be considered for southern facing banks of windows to limit the amount of UV damage to interior surfaces. A higher number of the north side of a home would allow more daylight inside, while using smaller expanses of glass.
Air Leakage — This optional rating appears as a number between 0.1 and 0.3. A lower number is desirable as the window will keep conditioned air inside and outside air from filtering in, providing better energy efficiency. A lower number here would also indicate that proper mechanical ventilation systems should be included in the design to maintain healthy interior air quality.
As with many elements of a home, windows need to comply with local code requirements at minimum. A low-U-Factor series of windows may exceed the code requirements but will provide a long-term benefit of energy efficiency and comfort over the life of the home.
The Andersen 400 Series Windows included in Katahdin packages were selected for their superior energy efficiency, as well as variety and style. They are available in six exterior Perma-Shield colors, which never require painting, and either natural pine or white interior finishing. Windows are shipped separately from Andersen direct to the Katahdin construction site.