Passive House design reduces the carbon footprint of the built environment through low energy use, air-tight building envelopes, and sophisticated ventilation systems. Windows and doors play a key role in keeping wind and variable temperatures at bay while allowing views and natural light in. The selection of fenestration products for a Passive House home can be the determining factor of whether or not certification is achieved. Passive house windows and doors must meet (or exceed) stringent standards for the coveted performance values. With this in mind, the window and door selection process includes several different variables to determine efficiency.
Glo windows and doors have been utilized in multiple Passive House projects. Here are a few key factors to be considered when shopping for fenestration products. The first evaluation is U-value and R-value. These figures will tell you how well the window or door does at keeping heat from entering or leaving the conditioned space. Our windows and doors have u-values starting at U-0.28 (and lower) or conversely, R-3.57 (and higher). This series is the A5 double-pane, which is our lowest-performing window. Although this is our “lowest-performing series” it has been successfully utilized in Passive House projects obtaining certification. The double-pane low-iron argon-filled glazing units, multiple-air seals, superior thermal break, and Low-E coating are all pivotal characteristics of a Glo window and Passive House windows and doors.
Other contributing factors that can be adjusted based on climate and need is the solar heat gain coefficient (SHGC). This value determines the amount of direct or indirect solar radiation entering the window which can provide heat regardless of the temperature outside. A window or door with a high SHGC will capture heat during the day which will, in combination with thermal massing, be retained through the night creating “free heat” for the home/building. Conversely, a low SHGC will block much of radiation and maintain cooler temperatures even in full sun. The higher the number the more solar radiation heat is retained and the lower the number the less heat is retained. This becomes important depending on location. For example, a home in Southern California will have vastly different SHGC requirements versus a home in Fargo, North Dakota.
Evaluating your location and energy model will determine what glazing properties and whether double-pane or triple-pane windows and doors will be best for your project: Glo Windows and Doors can meet both needs.