Heat rises. That's a fact. As there is no higher place in your house than the attic. In the summer, your attic can become a sweltering cauldron of painful heat. A lot of people just close off their attic, fill it with junk and forget it about. Not the most effective use of the space. Plus, all that hot air at the top of your house will raise your electric bills. Air-conditioning a space like that isn't a great option, energywise. You may consider venting it with a solar-powered attic fans?
A solar-powered roof vent or attic fan sits on the top of your house and vents your attic air, and it is powered completely by the sun. It doesn't add to your energy bill, and it doesn't contribute to climate change. In fact, because your house is cooler in the summer, you'll be using less energy. A solar-powered roof vent also reduces moisture build up, prevents ice dams from forming in the winter and extends the life of your shingles. Not only will this nifty gizmo lower your utility bill, it will protect the quality of your home.
They are not without a downside, however. Many of these fans don?t store energy, so if it?s cloudy and muggy day, your attic will go unventilated. Some attic vents supposedly turn off if a single cloud flies overhead. And they are disallowed in some high-hurricane areas, because they cause a structural weak spot in the roof. (Weak compared to a hurricane.)
The biggest downside is that they cost a few hundred dollars each and you need one attic fan per 150 square feet of attic space if you want your attic to be properly ventilated. That's a quite a bit of dough.
Now you know the possible downsides. Remember, not all attic vents are created equal. Look for brands that come with shade busters, have the capacity to store energy or utilize battery back-up. You should also look at the climate where you live. These vents probably won't be that great in Seattle. They have some merit in rainy places because of their ability to reduce moisture, but they won't be able to work at their maximum capacity. They seem best suited to places like the American Southwest and hot tropical areas.