Q–Our new Victorian home has a very tall roof. During the summer, it gets very hot on the second floor. We have central air conditioning, but the thermostat is on the first floor, which stays quite cool. I have been thinking about getting a solar attic fan to draw out the hot air. Would that help keep the second floor cooler? Would a reputable roofing company be able to install it for me? Any advice?
A–An attic fan can’t hurt, but it’s probably not the solution to your warm second floor, says Michael Chimack, a senior research engineer at the Energy Resource Center at the University of Illinois at Chicago.
“Overall, it sounds like the house has a problem on the second floor with proper ventilation from the heating and air conditioning system,” he says. “The second floor is too hot because it’s not getting enough cold air. That’s a common problem with two-story homes.”
That means that a solar attic fan may pull hot air out of the attic, but it will only result in a temperature drop on the second floor of a couple of degrees or so. In other words, it still will be uncomfortable upstairs.
Before you install an attic fan (and a heating and cooling contractor is more likely to do that for you than a roofing company), there are a couple of other things to try, says Chimack.
The first is to close the air vents on the first floor of the home and make sure the vents on the second floor are wide open.
Next, you can try dialing down the thermostat a few degrees to see if that will make the second floor any cooler. Of course, that means spending more dollars on your electric bill.
Finally, on sunny days, make sure you keep blinds and/or shades closed on windows facing south and west. “There are a lot of windows on a Victorian and you want to try to avoid any passive solar gain,” says Chimack.
What may be a more effective solution than a solar attic fan, he adds, is to install separate heating and cooling systems for the first and second floors. While an expensive investment initially, such zoned systems are highly efficient.
For example, at night while sleeping, you can turn the downstairs thermostat up, while keeping the upstairs cool, and save energy dollars. Actually, most of the savings will come in the winter months with your heating bill.
You can also try investing in a whole-house fan, says Chimack. “It wouldn’t be that much more expensive than a solar attic fan but may bring better results,” he says.
This, however, will require some daily maintenance.
At night, when the temperature drops, you can shut off your air conditioner, open the downstairs windows and turn on the whole house fan.
That fan will draw the cooler night air into the house and exhaust hot air through attic gable vents. In the morning, you can close the windows, shut off the whole-house fan and turn up the air conditioner as needed.
“People who have whole-house fans love them and they’re a medium-cost solution,” says Chimack.
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