A Little Shade Makes A Green Difference
A new study finds that awnings over windows in residential buildings can reduce energy use.
A new study, “Awnings in Residential Buildings: The Impact on Energy Use and Peak Demand,” conducted by the Center for Sustainable Building Research at the University of Minnesota, has found that awnings over windows on residences can save energy costs and reduce energy use throughout the year by reducing the effects of unwanted passive solar heating.
The study was funded by the Professional Awning Manufacturers Association (PAMA), and was conducted to determine whether awnings are viable means to reduce energy use and reduce air conditioner usage in residential buildings and homes. The study investigated the energy savings for single-family homes in terms of heat gain, energy costs in heating and cooling and the reduction of energy use during peak periods.
- » See also: Greening Your Home
- » Get Green Building Elements by RSS or sign up by email.
The results illustrate that in predominantly cold climates and mixed climates the highest energy savings are achieved when awnings are used in the summer and retracted or removed in the winter. Hot climates benefit from awnings year round, but because they are typically used year round, there is less overall energy savings when compared to the cold and mixed climates. Removing awnings during the winter helps to increase sunlight-related heat gain by allowing more light into the home.
It’s a little funny that a PAMA-funded study had to be done to figure this out when many, if not most, people probably figured this out themselves to some extent. There’s a built-in advantage for people at higher latitudes: the summer sun is much higher in the sky than in the winter, making it possible to design a fixed awning that allows full sunlight penetration in the winter (allowing for passive heating) and minimal penetration in the summer. In Europe (at least the German-speaking areas), shutter and retractable awnings are very much in use. In fact, in the new energy efficient constructions, especially houses made to maximize winter solar gain, electronically controlled window coverings are automatically deployed to minimize summer overheating. While on this topic, I’ll also mention a neat use of the different solar elevations in a building material developed by Dietrich Schwarz. It serves four functions, that of transparent heat insulation, protection from overheating, energy conversion and thermal storage. Do you encourage people to leave links to other sites? In case not, an internet search for GlassX limited to the domain .ch (for Switzerland) should lead you to the English version site).
tset, thank for your insight. I agree that a PAMA study probably wasn’t needed, as this is pretty common sense. It’s nice to know that they want to communicate in terms of energy reduction and savings, however.
This story drew my attention because I have been reading about buildings applying large-scale fabric scrims to the outsides of their structures to reduce passive solar heating and to create a layer of insulation which has dramatically reduced energy costs. I haven’t found any studies that document the savings yet, though.
Just look at the old eyebrow windows in Key West.
I think people are looking for simple, energy-use-reducing solutions that they can apply to their lives that don’t involve moving the giant wheels of government!
You can start to make the sustainable living changes at home yourself, and right away. An awning is a simple, smart idea that people have forgotten about, that doesn’t require rebuilding your house from the ground up.