Would a gable fan in attic help with cooling costs?
Bigdogdaddy
| Posted in Green Products and Materials on
I had radiant barrier insulation installed in attic, and so far I can not tell that it is helping. Was wondering if a gable fan would benefit me.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Search and download construction details
Replies
Elvis,
This is a fairly common question whenever things get hot. The problem is you are trying to address is heat gain from the attic. In order to prevent that from happening, the most effective thing you can do is air seal the attic floor and insulate. Then it doesn't matter what the attic temperature is. You have uncoupled the living space thermally from the attic.
Homeowners are often tempted to buy a powered fan (or a solar powered fan) to draw out the hot air from the attic, but the result is that it tends to suck cooler air from the home and bring in warmer outside air through the air leaks in the building enclosure. The attic will be cooler, but at the expense of increased energy costs to cool the home. This is assuming the house is not very well air sealed. See the article "Fans in the Attic"
One reader recently asked the same thing - venting the attic in a 100 year old house in Wyoming. There were some good suggestions from Martin Holladay and Dana Dorsett in that answer.
Martin Holladay referred the owner of the home in Wyoming to an article he wrote called "Energy Upgrades for Beginners". It is very informative and talks about inspecting your attic and the energy upgrades you can make to improve comfort. And the article really applies to anyone.
There is a very spirited discussion about solar-powered attic fans by building scientist, Peter Yost, "Are Solar-Powered Attic Ventilators Green?". It presents the pros and cons of this particular type of attic fan.
I hope one of these references will help you make your home cooler.
References:
1. GBA "Fans in the Attic: Do They Help or Do They Hurt?"
https://www.greenbuildingadvisor.com/blogs/dept/musings/fans-attic-do-they-help-or-do-they-hurt
2. GBA "Radiant Barriers: A Solution in Search of a Problem"
https://www.greenbuildingadvisor.com/blogs/dept/musings/radiant-barriers-solution-search-problem
3. GBA Q&A "100+ year old house in Wyoming with hip roof is hot as heck — should we vent it?"
https://www.greenbuildingadvisor.com/community/forum/energy-efficiency-and-durability/27829/100-year-old-house-wyoming-hip-roof-hot-heck-
4. GBA "Energy Upgrades for Beginners"
https://www.greenbuildingadvisor.com/blogs/dept/musings/energy-upgrades-beginners
5. GBA "are Solar-Powered Attic Ventilators Green?"
https://www.greenbuildingadvisor.com/blogs/dept/building-science/are-solar-powered-attic-ventilators-green
Elvis,
Q. "I was wondering if a gable fan would benefit me."
A. Probably not. In fact, a gable fan is potentially dangerous.
There are better ways to spend your money (for example, reducing air leaks in your ceiling, or installing thicker insulation on your attic floor, or sealing leaks in your attic ductwork, or improving your duct insulation). Installing a gable fan will probably make your energy bills higher, not lower.
Read all about these facts here: Fans in the Attic: Do They Help or Do They Hurt?