Natural lighting is a great way to save energy as you illuminate your home without electricity during the day. However, windows can also be a source of expense during hot or cold weather. In warmer climates that require a significant amount of cooling energy, windows with clear glazing can represent 40 percent of the air conditioning costs or more. More energy-efficient options like double pane windows can still account for 25 percent of the cooling energy used in these settings. Paying attention to your windows may provide insight into potential energy savings opportunities.
How Windows Affect Your Home Comfort Costs
According to an energy efficiency report prepared for the U.S. Department of Energy, a window is not much different than a hole in the wall as it relates to your home’s insulated envelope. Walls tend to be insulated, providing a barrier that slows energy transfer into and out of the structure. Energy loss through windows can be more than twice the loss through a wall, and increased energy loss results in more heating or cooling energy being required to achieve desired comfort levels in your home. Heat gain or loss can be affected by issues like the area of a window, the efficiency and glazing of the glass, and the positioning with regard to sunlight and other external elements. These issues are included in calculations of your heating and cooling load anytime new HVAC equipment is installed.
Strategies for Lowering Energy Expenses Related to Your Windows
There are numerous options for countering heat transfer through your windows. Some are more costly, requiring structural measures. Others are quite simple and affordable. Your home improvement budget may be a factor as you determine which steps to take. However, it’s also important to recognize that energy savings may offset the costs of more expensive solutions.
Upgrade to Double Pane Windows
Two layers of glass may reduce the loss of heating and cooling energy in your home. However, you should be aware that clear glass still contributes significantly to air conditioning loads. Look for windows that have been treated to filter wavelengths that increase heat gain. ENERGY STAR qualified options include the following performance ratings:
- Air leakage – a measure of the rate of air passing through joints in a window
- Condensation resistance – a reflection of the potential for moisture buildup between panes
- U-factor – a measure of the rate of heat transfer
- Solar heat gain coefficient – a measure of how well a window blocks heat that is caused by sunlight
- Visible transmittance – a measure of the amount of light allowed through a window
It may be helpful to discuss these ratings with an installation expert in the community who is familiar with environmental conditions and ENERGY STAR products.
Make the Most of Window Treatments
Insulating curtains may provide an extra barrier to incoming heat, allowing you to reduce the energy loss experienced during both summer and winter months. Studies indicate that heat gain during the summer may be reduced by up to 33 percent when curtains with medium colors and white plastic backings are used. Additionally, up to 10 percent of heat loss may be prevented with conventional draperies during the winter. Maximum efficiency in both scenarios occurs as the drapes are placed closer to windows. Additional window treatments to consider include:
- Blinds – reflective blinds can reduce heat gain by more than 40 percent
- Window shades – similar to blinds in reducing heat gain, but limited in allowing natural light into the home
- Reflective films – greatest impact is obtained on windows facing east and west
- Solar screens – excellent for windows facing south, east and west
- Shutters – provide insulating effects as well as weather protection
Consider Weather Proofing
Weather stripping and caulk may allow you to reduce the flow of air into and out of your home. Old caulk and weather stripping should be checked seasonally and replaced as it deteriorates. Energy Star estimates that a combination of air sealing and attic insulation can trim as much as 10 percent from home comfort costs.
HVAC Solutions for High Energy Usage
As you consider the role of your windows in your energy bills, don’t neglect HVAC maintenance and ventilation needs. You may find that an energy recovery ventilator allows you to keep fresh air moving into your home without the energy loss experienced through window ventilation. You may also discover that your high bills are connected to equipment that hasn’t been optimized recently. If you need assistance with these issues in your Hagerstown, MD, home, call us at Griffith Energy Services to schedule an energy audit or to discuss your concerns.
Written by Kevin Spain