Decorating & Design
January 13, 2009
Summer Cooling Tips
Solar heat gain is brilliant in winter, when it can help warm up your home. But in the summer, when the sun is at it’s highest and the heat it transfers inside the house makes air-conditioning work overtime, those extra degrees can be overwhelming. Use these tips to keep your home cool.
South, east and west-facing windows can create overheating problems in the summer months, when the sun is low enough in the morning and late afternoon to shine directly into them. Windows facing these directions can gain as much as 235 BTUs (British thermal units) per hour in the midday heat. Heat gain through skylights can be even greater, posing a further cost-threat to summer cooling efforts. For a new home, consider the placement of your windows in relation to the climate you live in.
If it’s too late for a window-placement redesign, consider other ways to limit solar heat gain. Outbuildings, overhangs, porches, awnings or trees (preferably deciduous) can help to block sunlight from windows. Exterior shading treatments are approximately 50% more effective than internal window coverings at blocking solar heat, but can be an expensive add-on and their design should work aesthetically with the rest of a home’s exterior.
One of the easiest and most cost-effective ways of controlling solar gain is the use of window coverings. Lowering shades or drawing drapery to block out the heat of the sun can help keep the interior of your home cool, decreasing the need to run air conditioners or fans for long periods of time.
Large custom windows or floor-to-ceiling condo windows, which can be difficult to fit with window coverings, benefit from solar film which can help control the amount of sun and heat that penetrate the window. While this type of product may deteriorate after a few years, professional installation can ensure a longer lifespan, about 8 to 10 years.
A more permanent though costly option is to install specialty window glass that has a greater shading cabability built into it. When researching new windows, check with the manufacturers to find out if they offer windows with one or more layers of low-e (low emissivity) coatings in their product. This technology works by reflecting heat back to its source and can help protect furnishings by screening out damaging UV rays. A coating of low-e is roughly equivalent to adding an additional pane of glass to a window and can reduce long-wave radiation heat transfer by 5 to 10 times.
Some manufacturers also inject argon gas into air spaces between the panes of glass. Environmentally safe and inert, argon gas significantly reduces the conduction of heat.