Keep your Cool this Summer – Without the Cost of A/C
By N. R. Mallery
Keeping indoor spaces at comfortable temperatures requires huge amounts of electricity. In the U.S., it accounts for a full 16.5% of energy use.
There are many options that can help you keep cool while also conserving your energy.
SHades. Window shades may help improve energy consumption and lower energy bills by keeping homes cooler in summer and warmer in winter.
Most Efficient Shades. There are many types of window shades available, but the U.S. Department of Energy states that dual shades are more efficient than regular shades. Dual shades have a white, heat-reflective side, and a black, heat-absorbing side. The white side should face the window during the summer, and the dark side should face the window during the winter. Quilted and honeycomb window shades contain several layers of material and are sealed on the end to provide insulation and prevent air seepage.
For the greatest energy efficiency, place the shades as close to the window and walls as possible. In summer, keep shades lowered on the southern side of the house during the day to limit the amount of heat entering the room. In winter, shades on the southern side of the house should be up during the day to increase the amount of heat entering the room. Window shades are particularly effective in improving the thermal condition of inefficient windows.
Solar Screens are heavy-duty window coverings, used for reducing heat absorption and sun glare, reducing the absorption of heat through the window by about 80-90%. At the peak of summer, up to 230 BTUs per hour can hit each square foot of window. A solar screen operating at 80% efficiency would block 184 BTUs per square foot from reaching your windows each hour. Alone, they can reduce the temperature of a room by 10°F to 15°F. This means less use of the air conditioner during the summer months; consumers have reported a 15 to 25% reduction in their energy bill. Usually made up of heavy duty woven mesh, they absorb and reflect solar heat before it actually enters the windows. Sun-shielding solar screens add function, style, and efficiency to home and businesses, offering you the choice of how much sun to allow in your space, giving you control of light and heat gain. The darker shades are functionally more effective than the lighter color solar screens.
Awnings and Porches. Keep summer’s hot sun out of overexposed windows. Awnings are cost- effective in blocking hot sun from radiating through windows and decrease air-conditioning bills in the summer. A commercial awning also protects patrons from the elements in front of a store. Retractable awnings allow solar gain in the winter. They also create shelter to stay out of the suns for protection against the harmful UV Rays. Porches are permanent, so if you want the heating advantage of solar after the summer, you will want to consider this and locate them with this in mind. Enclosing porches in the winter serves as a block from the elements on the north side of your building, helping to reduce heat loss.
Shading. Reduce summer electric bills with shade trees.
Shade trees can save you money! Scientists have shown that properly placed trees can reduce your summer electric bills by as much as 35%. Called “Tree-based Energy Conversation,” they are a low-tech solution to a high-tech problem.
- Plant windbreak conifer trees on the west and northwest to provide mid-to-late afternoon shade in most locations. In winter these windbreak trees protect your home from cold north winds. But note that trees planted within 15 feet of the north side of a house actually increase summer electricity use, because they trap heat. For a windbreak, plant far enough away to prevent the trap effect.
- Shade east and west windows with deciduous trees, but prune lower branches to prevent blocking the view. In winter, after leaf fall, warming sunlight comes through.
- Plant shade trees over patios, driveways, and air conditioning units to cool areas around your home.
Trees for Saving Electricity. Tall maturing, deciduous trees (hardwoods) are generally recommended for shading because they cast the largest shadows. Importantly, they also drop their leaves in winter when you want the sun to help heat the house. Select trees with dense canopies. Planting a tree or shrub to shade your air conditioning compressor can increase cooling efficiency as much as 10%.
You can estimate the benefits, in dollars, provided by trees around your house by visiting arborday.org/calculator/index.cfm?