There are actually several factors that make a window energy efficient. First off, choosing the right glass package for your home’s windows is critical in ensuring energy efficiency so you can be as comfortable as possible while saving on heating and cooling bills. The brand you choose will also have a big effect. Your technician likely has a favorite he or she likes to work with. Here at Rescom, we work exclusively with Bristol.
Here are some factors that go into whether a window is considered energy efficient:
- Panes of Glass: New windows have double pane or triple pane, meaning they have either two or three panes of glass. Generally, double is better but always ask your technician which is best for your home.
- Spacers: Here at Rescom, we use the Bristol spacer, which offers superior insulation and thus higher energy efficiency year round. The Bristol windows we install feature the BR50 Enviroseal Spacer System, the most advanced structural spacer on the market today. The BR50 spacer makes a seal that can form a barrier against air and moisture, plus the spacer material itself gives even more thermal protection.
- Gas Fill: These are non-toxic, inert gasses that are used between panes of glass instead of air. This helps to boost insulation and energy efficiency. Argon or Krypton gases are best, because they make it tougher for heat or cold to transfer through the glass.
- Low E (Emissivity) Glass: This is glass with a transparent, multi-layer, metallic oxide coating that is applied onto a glass surface. The coating works to reflect energy, thereby improving the window’s insulating U-factor.
- Solar Heat Gain Coefficient (SHGC): This is the ratio of the solar heat that is gained through a window to the solar radiant heat incident on the outer part of the window.
- U-factor: This is a measure of the rate of heat conduction that gets through the surface of a window. The lower the U-factor, the better, because it means it’s doing a better job keeping out heat and cold via conduction.
You can get a good idea of the energy efficiency of a window by reading its NFRC label. The National Fenestration Rating Council (known as NFRC for short) is the entity that provides testing, certification, and labeling of windows, doors and related products based on how well they perform in regards to energy efficiency.
This label helps installers and homeowners compare properties of energy-efficient windows, doors, and skylights by providing energy performance ratings in multiple categories, says the NFRC.
Contact Rescom Exteriors
To learn more about what makes a window energy efficient, particularly our Bristol windows, contact us today!