Is Your Roof Cool?
Sustainable architecture is a great way to reduce your carbon footprint. One element to consider during the process of making a home more green, is by making the roof cool.
First of all, what is a cool roof?
A cool roof is one that reflects heat and solar radiation, therefore reducing the heat that is brought into the house. This way, electricity usage is lowered as well as costs for the home-owner. Copper roofing or special paint pigments can be used to get a cool roof.
The process of keeping your roof cool is similar to the difference between wearing a black shirt or a white shirt on a hot day. One material will absorb the heat while one reflects it.
So, how do you know if you are getting the results you want?
There are a couple tests you can do to see if you have a cool roof.
R - Reflectance
Reflectance is one of the ways to assess your roof’s cooling properties. This test measures the amount of solar energy that is reflected from the roof.
E- Emittance
Emittance refers to the the infrared radiation energy that the roof emits.
Both Reflectance and Emittance are measured on a scale from 0 (least reflective/emissive) to 1 (most). The tests are done both right when the roof is built and it has been three years since construction.
So, a white roof will reflect more infrared sunlight while a darker one will absorb more. This is not to say that you need a white roof for cooling, because there are some darker colors that can reflect, but in general the white roofs are more efficient.
Cool Metal Roofing
Metal can be used to help the cooling process. The metal itself can even be shaped to look like shingles (if you prefer that look) and can be formed to fit a wide variety of roofs. There is a diverse selection of colors and textures to choose from so it can still fit your personality and design preferences.
If you are using a copper roof, which changes over time, your level of cooling will be affected. It is important to take this into consideration when choosing which type of metal to use.
Need more reasons to invest in a cool roof? Since your house will stay cooler, your air conditioner will last longer. And, in some locations, you can get a utility rebate.
Cool roofs are affordable, too. Typically, the cost of installing one is comparable to installing any other type of roof. Since you’re saving money on your power bill and potentially receiving a rebate, it is definitely worth it to install a cool roof.
Some areas are even starting to have building codes that require that you meet cool roof guidelines.
Having a cool roof benefits the environment and your wallet. So, is your roof cool?
Learn more here: http://www.copper.org/publications/pub_list/pdf/a4094.pdf
And here: http://coolroofs.org/
-J.C.
