Tom Edwards has been an architect for 40 years and his clients have amazed their neighbors with this near-zero cost way of cooling an old house – but note this only works on houses with an attic and a hatch – which is many millions of houses but by no means all.
The principle at work: “nature hates a vacuum”. Something rushes in to fill it.
Thus, as heat rises to the ceiling in your building and is trapped there, you should let it out. Open the attic access panel, usually in your hallway ceiling, during the summer, attach, and keep attached during the summer, the largest fan that will fit in it, pointing up, to shoot that heat up into the attic. Then, as the attic is already hot like an oven, you also go up and attach another large fan to a gable end vent, blowing outward. I wire them safely to avoid shorts, etc, then have a switch inside a nearby doorway which I turn on and listen for attic fan. When I hear that it’s on I turn on the access hatch fan.
Then – this is critical – close every window in the place except the one on the coolest side of the house. Nature, then, offended by the vacuum you have created, pulls in that coolest air, which can lower the temperature by many degrees, on its way to the attic, while creating a nice breeze. So I put my work space right by that window.
The fans together use a tiny amount of the power and AC would use. Neighbors walk in and can’t believe it’s not air conditioned.
Find more tips on how to cool your home without air conditioning here: www.localcooling.com/
This is a great, low cost idea. I would also suggest a small but obvious tip: keep your shades down and your windows closed during the hottest times of the day. I have noticed that the rooms that I do this are actually cool, whereas the rooms that I live open to the sun are a good 5 degrees or more higher.
I’m a HVAC contractor in the mid-south and do a lot of attic work with both central air system replacement and thermostat controlled attic fans and ventilation.
Tom Edwards whole house idea isn’t new, whole house fans have been around along time.
But here, where the humidity can be severe in the summer, especially this year, you have to close everything and turn on the a/c to survive.
At Ft. Sill Oklahoma, there are some buildings constructed during the 19th Century that use this technique. In addition, they are build of heavy masonry to act as a thermal mass, which keeps the temperature fluctuations to a minimum. Air is drawn from a deep basement area and exhausted at the roof. I was in one of the buildings one day when it was over 40 deg C outside, but the interior was very comfortable.
It had zero power use save a thermal gradient.
There is also another way you can do the same, put what they call up ducts in each room, put a thermostat on the ” gable end fan”, then when it turns on to suck the hot air out of the attic, it will aoutomagicaly open the up-ducts to release the hot air in the rooms.
The whole concept is very much do-able for the average diy-er with a big box home improvement store near by. Instead of trying to figure out what fan will work and which one won’t, they have these fans available at reasonable prices designed to do exactly as explained in the article. A “whole house fan” to pull the air out of the house and into the attic and a “gable end fan” to expel the hot air in the attic. Great article!
I think that it’s crucial to remember/know that fans “blow” much better than they “suck” – which is why fans designed to draw air away from something have “squirrel cages” built onto them. There will always be baffling or a restricted housing surrounding the fan blades, otherwise the air movement will be AROUND the blades, instead of forward or backwards. This idea makes Mr. Edwards use of a fan at the “attic access panel” significant, as a fan in this (restricted) location will force the fan to “suck” from the hallway (or house area below the access panel) and “blow” into the attic. I would go a step farther and say that the fan attached to the house (“gable end”) vent(s) should have a housing that pulls the air (that is blown out!) from as deep into the attic as possible.
Interesting. The first part is self explanatory but not 100% sure I’m properly visualizing the second part. Does Mr. Edwards have a website or are there other sites that might have video or pictures of this set up?