Attic Fans & Ventilation
Archived Q&A and Reviews
Attic Venting
August 2008
There is an attic space right off of my bedroom that we use for storage. It is unfinished. During warm/hot weather, the attic heats up and makes the upstairs unbearable. There is currently one small exhaust fan installed but it isn't doing much. Can you recommend a service or company to vent and properly remedy the problem? Thank you. Amy
Rule of thumb is about one square foot of venting for every hundred square feet of attic. More if your shingles are black. Contact any good roofer for attic vents. I suggest Shamus Collins. Cliff
Whole House fan wanted
August 2006
After suffering through the recent heat wave, my husband and I have decided to get a whole house fan installed in our attic. These large fans draw up hot air from the house and blow it out the attic, replacing it with cooler air from outside. We are looking for a recommendation for an experienced installer and the type of fan installed. We would also like to get feedback on the fan's effectiveness. Thanks! Susan
The fan you want is the solafan. Its a solar powered unit placed in the roof to suck all the hot air out of your attic. Cooler air is replaced from below. You can purchase the fan at any builder supply, and can recommend Economy Lumber Company in Oakland as my supplier. lj
In reply to the person looking for info on whole house fans - visit BuildItGreen.Org and send an email or call the ask the expert hotline.. They'll have lots of info on whole house fans- - check out the list of Certified Green Building Professionals on their website to help install one. My friend has a whole house fan and was really impressed how it cooled down the house once the air outside was cooler than inside. Instant relief - especially for a two story home. Good choice! meri
Solar Star Attic Fan
August 2004
I wonder if anyone has installed a solar-powered Solar Star attic fan in their home and would be willing to share their experience. I looked on the archives and didn't find anything. My concern is that the fan might actually cool our Berkeley house too much during ''normal'' spring, summer, and fall days when we rely on the heat of the afternoon to warm our house after it has cooled down at night. Yet the Solar Star seems like the perfect solution to those horrible 5-10 days a year when it doesn't cool down at night and our house is unbearably hot. It's also supposed to help improve the efficiency of your heating system in the winter by keeping the attic cool and dry. Anyone who'd like more information on the Solar Star, check out www.solatube.com. Ashby Lumber carries these fans but they are not at all knowledgeable about their operation. Maria
Solar Fans - I have one installed in my house - have one fatal flaw. They only cool during daylight hours. You need to circulate cool air into the attic space once the sun goes down, or the attic remains warm through the night and the cycle starts again in the morning. Also, our fan does not move enough air to cool the attic space - I ended up using the fan motor and adding a low-voltage power supply to it to keep it running through the night. tjay
I would love to share what we did. Though our house is quite a bit larger than yours, this method still worked, and we are so pleased I took the time to research a more environmentally sound solution. We installed two QuietCool whole house fans (you would only need one). For the days of smoke and extreme heat, we use a portable LG AC, the highest rated one available, which we bought at Home Depot; we vent it out our chimney rather than window so it takes up less space. So far this year it hasn't been needed once, and we store the AC in our garage for most of the year. Not only is AC very expensive, it's also terrible for the environment, and shuts people inside their homes. I've been saddened by all the people in our neighborhood running AC this year, which can be annoyingly noisy, when they could just run whole house fans when it's cooler outside!
An added benefit of whole house fans is that you refresh your home with outdoor air every time you run it. Our house feels and smells great during and afterwards - a beautiful gentle breeze flushes the house. Outdoor air is healthier than indoor on all but smoky or other disaster days.
With the whole house fans, there are a few things you should know, which many consumers overlook. I called the manufacturer and discussed our attic ventilation with them. We needed to increase attic ventilation in order to have enough space for the heat to vent out effectively; we hired a roofer to add some vents. Many people skip this step and then the unit doesn't work optimally. (They also offer a model for homes without attics.) The whole house fans lower your home's thermal mass, so the home stays cooler, even when you're not running the unit. The fans are very quiet when run on low; on high they are noticeable, but the sound doesn't bother us. Aside from ensuring proper flow and unit size, we also got skylight covers and window shades for the windows that didn't already have them. We also bought outdoor umbrellas for our patio, and continue to grow a garden with shade trees. All of this results in a home that is wonderfully cool and feels connected with the environment. Before we took these measures our home regularly exceeded 90 degrees, which was unbearable for indoors; now on the very hottest days the house does get into the 80s, but cools down once we can run the fans because it's cooler outdoors, maybe starting around 6 pm, depending on the day. And if we really can't stand it we can set up the AC as needed, rather than run AC as default.
When our furnace goes (in a few years?) we will replace it with an electric heat pump, which also runs cooling; if you're going to do AC this is the quieter, more environmentally sound way. We will still run the whole house fans for at least 95% of the year; the AC function would only be utilized on the hottest, smokiest days.
Elizabeth