12 Tips to Green your home’s Windows
Windows – By following the tips below, you can begin to reduce your energy consumption and the effects your windows have on the environment.
✔ Consider EnergyStar rated windows – Installing EnergyStar qualified windows can reduce your energy bills and carbon footprints by about 7-15% compared to non-qualified products.
✔ Install multiple pane windows – Two or more panes of glass, with an air or gas filled space in the middle, insulate much better than a single pane of glass, provide increased impact resistance, and sound insulation.
✔ Install windows with warm edge spacers – A spacer keeps a window’s glass panes the correct distance apart. Nonmetallic and metal/nonmetal hybrid spacers also insulate pane edges, reducing heat transfer through windows.
✔ Consider installing storm windows – Installing either exterior or interior storm windows can cut heat loss through your windows by 25 to 50 percent.
✔ Add window film to existing windows – Installing a window film or adhesive coating can boost the efficiency of your current windows by reflecting sunlight and reducing its transmission into your home or office as heat.
✔ Seal window air leaks – Sealing air leaks can reduce heating and cooling energy costs, enhance a building’s durability, and contribute to a healthier, more comfortable indoor environment.
✔ Consider low-e windows – Low-E stands for low emittance. The glass is coated with a virtually clear material that acts to cut the transmission of ultraviolet rays from outside to inside. Low-E glass further improves thermal efficiency of the window.
✔ Consider gas-filled windows – Modern window technology seals an inert gas (usually argon) between the panes of glass. The gas is a far better insulator than just air, so it further increases the window’s thermal value. Argon and krypton are the two most common options, either of which can be used on their own or in combination.
✔ Buy window draft stoppers – A draft stopper is a tube stuffed with insulating material that you place on the window sill or meeting rail to cut down on air leakage, especially in cold months.
✔ Use shades and window coverings – Lowering the shades, drapes, or blinds can prevent unwanted heat gain through windows on hot days or help retain interior warmth on cold nights.
✔ Check the NFRC label – The NFRC label can be found on all EnergyStar qualified windows and provides performance ratings in five categories:
- U-Factor measures the rate of heat transfer and tells you how well the window insulates. The lower the U-factor, the better the window insulates.
- Solar Heat Gain Coefficient (SHGC) measures the fraction of solar energy transmitted and tells you how well the product blocks heat caused by sunlight. The lower the SHGC, the less solar heat the window transmits.
- Visible Transmittance (VT) measures the amount of light the window lets through. The higher the VT, the more light you see.
- Air Leakage (AL) measures the rate at which air passes through joints in the window. The lower the AL value, the less air leakage. Most industry standards and building codes require an AL of 0.3 cf·m/ft2.
- Condensation Resistance measures how well the window resists water buildup. The higher the condensation resistance factor, the less buildup the window allows.
✔ Buy windows most appropriate for your climate – The most appropriate type of your window can be found by identifying your climate zone from the map below, and then looking up the optimal U- Factor and Solar Heat Gain Coefficient (SHGH) for your region. This can be done HERE.