What Makes Energy Efficient Windows Efficient?
With summer about to be in full swing, we’re all preparing for higher energy bills as we turn up the air conditioning to keep our homes cool and comfortable. But if you have older, non-energy efficient windows in your home, you could be spending hundreds of more dollars each month to cool your house, as the cold air escapes and the hot air seeps in.
Before you make an investment in green windows, educate yourself about some of the differences between energy-efficient windows and non energy-efficient windows:
- Air Infiltration: Older or improperly installed windows with unsealed gaps can account for up to 10% of your home’s energy use. Energy-efficient windows offer airflow protection, keeping cold air from escaping in the summer and keeping your home warm in the winter.
- Conduction: Conduction refers to the direct transfer of heat through the window, which can be reduced by using energy-efficient windows.
- Convection: When warm air from inside your home meets a cold window, a chilly, circulatory draft occurs. Energy-efficient windows reduce these convection-related issues.
- Heat Loss: Regular windows use clear glass, which can absorb interior heat and then radiate it outdoors. Energy-efficient windows use Low-E (short for low emissivity) glass coatings, which greatly reduce this heat loss.
- Solar Radiation: Solar and UV radiation in the summer can fade and damage furniture, and increase the cost to cool your home. Low-E microcoating in energy-efficient windows works to reduce solar radiation and provide UV protection.
- U Value: U Value, or thermal transmittance, is the rate of heat transfer between a window’s interior and exterior. The lower the U value, the better: lower U values mean greater insulating properties and thus greater energy efficiency.
Green construction products, like energy-efficient windows, are good for the home by insulating it from harsh summers and winters, the homeowner by saving energy costs, and the planet by reducing carbon emissions.
UPDATE: And just for a different perspective, Lloyd Alter from Treehugger reminded me that replacement windows aren’t usually the best “bang for the buck” – you can achieve the efficiency qualities below through other means (like weatherization).
Mark Kennedy heads the online marketing effort for Power Home Remodeling Group. Since 1992, Power Home Remodeling Group has specialized in providing exterior eco-friendly products for the home, including replacement windows, doors, siding, and roofing. Contact him at firstname.lastname@example.org.