My brother and his family are visiting us in Northern California right now. We are going through a hot spell and don’t have an air conditioner. We looked into putting one in a while ago, but since we are built into a steep hill, there was no economical place to put the compressor. My brother was suggesting that we get a whole-house fan. He briefly explained how this would work, and since we have an (unfinished) attic, he said it would work for us, and cool us off significantly.
Does anyone have experience with these? How much do they cost (for the machine and the installation)? What brands do you recommend?
Many thanks.
Jocelyn
Replies
A whole house fan won't "COOL" off anything.
What it will do is bring in the outside air so you can't get any cooler than what is outside.
Now I don't know what you climate is or insulation.
But I love my whole house fan.
In only run my AC during the most humid part of the summer. The other hot times I close the windows during the day and then in the evening open the windows and run the fan.
I have not priced one recently, but I think that they start at about $250-350.
If you have enough ventalation in the roof system and a place for placing the fan installation should not be very expensive.
You want a 2 speed, belt driven unit.
Even better are these Tamark units. They have insulated automatic doors and they are Quiet. But much more costly and don't move as much air. Probably more usefull in areas that have extrememes in both hot and cold.
http://www.energyfederation.org/consumer/default.php/cPath/30_407
"We looked into putting one in a while ago, but since we are built into a steep hill, there was no economical place to put the compressor."
Have you tried some "good" HVAC contractors the do more then installation in track homes. There are a large number of options. Roof mounted compressor is one.
Thanks for the info.
As for the AC we looked into, it was with a larger shop in our area. We are in an established area, so we don't have a lot of "tract" homes. Anyway, we didn't consider a roof compressor, but that might be out because of earthquakes. Thankfully, we haven't had one in a while, but the experts keep promising that it's coming.
Jocelyn
I put in the Tamarack HV1000. Like Bill said, it's quieter, but doesn't move as move air. It moves 1000 cfm, larger belt drives move something like 5 times more, I think. I only considered the Tamarack because it has insulated doors that open and close automatically.
We're in Woodland, CA (by Sac) and it helps cool the house down in the late evening when the outside becomes cooler. It was worth for us, because our 1930's bungalow only has window AC units and a non-forced air furnace. Just a new forced air furnace before AC was over $5K.
We are in the Bay Area. Did you purchase your machine at a local shop in Sacramento or a national chain? Also, does it cool things off during the day? We can't put in AC, so I am just wondering how effective this will be as a substitute?
Thanks.
Jocelyn
How it works during the day depends on a lot of conditions. If humidity is low then having the fan running during the day is almost always a winner, since it promotes evaporation from your skin and makes it feel cooler. (Open windows in occupied rooms first, to put the airflow where it does some good.)Another approach is to run the fan at night to pull in cool air, then shut the house and close the curtains to minimize heat gain during the day. Use room fans and the furnace circulating fan to move air around in the house and provide a breeze. Then only open the windows and turn on the fan during the day after it gets too warm to tolerate with them closed.If you have a basement, you can open windows in the basement and have the fan draw air up into the house. The basement is generally cooler, so you get cooler air in the rest of the house than if you open windows in upper floors.The main thing is to try to figure out how to work around the hottest part of the day, assuming the rest of the day is reasonably pleasant (at least relatively speaking).
Which city (airport) on the following list best matches your climate.http://www.weatherunderground.com/US/CA/I know that you are in the bay area, but if I am not mistaken between the bay, hills, and valleys you don't have to go far to have signficant different weather.
Quite so. We are about 20 north of Palo Alto. Our town is called San Carlos, and it has roughly the same weather.
Jocelyn
Here is the summary for the month todate.http://www.weatherunderground.com/history/airport/KPAO/2005/7/15/MonthlyHistory.html82 is the hightest hight so far.Lowes in the 60's or even upper 50's.Dewpoint 55-60.If that is typical summer weather it would be criminal to install AC.An whole house fan would be perfect.You will need to experiment with this, but probably keep the window closed during the day.Open then in early evening and run the fan for a couple of hours and then shut it off, but leave the windows open till moring.
82 seems a little low. My husband's thermometer said over 90 degrees yesterday. Our hottest days are in September and October, though.
Jocelyn
Jocelyn,
I have the Tamrak 1000 and got it on the internet. We live in Pleasant Hill - upper 90's every day this week. The insulation in our ceiling is only around R-11 right now; will be going to R-30 hopefully next week. Regardless, the house has been getting to around 84 by the end of the day. Once it drops below that outside I open all the windows and run the attic fan all night. The house gets down to around 72 by morning. Close everything up and repeat.
I got the Tamrak for the same reason as the other poster - insulated shutters. Our home is around 2100 sq ft, and it is a little undersized but definately quieter than the big single blade units. They make a couple of larger units now. They all qualify for PG&E rebates.
Wayne
I ordered mine from the company themselves. I don't know if they are sold in stores, but no doubt an installer could find one for you. They are on the web @ http://www.tamtech.com.
The fan simply sucks outside air in through your windows/doors and expels it through your attic vents. Sometimes it is required to add more venting so your attic doesn't become pressurized. If you have a furnace in the attic, a lockout switch is required so that the two can't operate together (not sure if that's national code, or just in Davis, where I work.
The fan will not cool your house if the outside air is warmer. Like the other poster, we use it to cool the house more completely overnight, so by 6pm the next day, it's not oppressive in the house. That's been tough this week (106 yesterday), so we used the window AC's for two nights. I think whole house fans should be required anywhere it's not too humid and the nights cool down enough. Much nicer to the planet than AC.
Can a whole house fan work with an insulated attic?Tamarack has a whole-house fan that might fit the bill, the TC1000-H. Only 800 cfm though. It would be nice if one could just get a motorized insulated hood to allow attic air to exhaust to the outside, then one could just go with the HV....
"Can a whole house fan work with an insulated attic?"Do you mean a conditioned attic; ie, the installation is between the roof/walls and the outside and not between the lower level and the attic?If so you can, but it will some work.The fan needs to draw from the conditioned spaced, that is the house or attic, and exhaust outside.There are large vent fans that mount on the walls or on the roof and ventr outwards. They are designed for bath and kitchen venting, but would work the same. But I don't know if any have good seals. Look at Fantech for some ideas.There are also gable end vents that have lovers on them.And with enough work you could possible figure out a way to mount one of the Tamarack unit with an exhaust duct to the outside. I have nto looked at it closer, but the Ghost unit might be easier todo that with.Another option might be to put of a dummy wall about 3 ft from the gable end and make that space vented to the outside. Could possible do something like that with a dummy dormer. Or a False ceiling in one area to mount the fan and the area above it would be heavly venrted.
I think the TC1000-H is like those bath/kitchen fans, but bigger. Has 1/2" foam insulation on the damper, that opens and closes automatically.My concerns: (1) As you say, how good is the seal on these things? (2) If I put a piece of machinery on an outside wall, sort of like a window, what happens when it wears out and has to be replaced? (3) At first I liked your idea of the fake inside wall, but then thought that that's just moving the issues to the fake wall instead of outside wall.I'm thinking that the best solution may be awning windows in the attic gable-end walls (awning because they can be left open in the rain) and then whole house fan in attic floor. It does require going up into the attic to open and close windows, but the low-tech solution has the advantage of less maintenance worries....
We have both whole house fan and AC. The fan is a Sears direct-drive unit, and we don't find it to be noisy enough to bother us (noise being the usual complaint about direct-drive). This unit (now about 20 years old) was designed for DIY installation and was fitted with a plastic box that could straddle ceiling joists to avoid the need to cut joists. The shutter grille mounts below the ceiling to similarly avoid the need for cut joists.
My wife is a big complainer about drafts, but has never complained of a draft coming from the shutter in the winter. I suppose it could be that this is because of air leaking the other way, but we've had no indications of that (snow/frost melted on the roof above the unit, frost in the attic, etc).
Forgot to add: We don't really like running the AC except when it's exceptionally hot/muggy (like now). We're not just stingy -- we prefer the fresh air.
Edited 7/16/2005 11:56 am ET by DanH
We don't have snow here, and it doesn't usually get below 40 degrees at night in the winter. Sounds like this would be a good way for us to go.
Thanks.
Jocelyn
Your house was able to be built level on the big slope. You could definitely have a condensor leveled out somewhere. On pile foundations & coastal applications, we have put them on an inconspicious side of a wrap around porch. Actually a small platform could be built off that with a decorative fence or something. How aboout concrete?.....Just ideas
I love Central Air!!!
Humid NY,
Erik
We have a slope on the side of the house that could hold one compressor (on a platform). It would only be for the upstairs part of the house, though. The question was where to put the compressor for the downstairs. We were out of places. There isn't room for two side by side or top to bottom. We almost put in just the one to help but chickened out. My son was just Bar Mitvahed last week, so central air is out for this year.
Jocelyn
If the humidity is low enough how about swamp coolers?
I give up. What's a swamp cooler?
Jocelyn
Uses water to evaporatively cool incoming fan pulled air. Very common in southwest US. Usually mounted on roof. Earthquake issues - I don't know.
Was in Sacramento last winter. Riding the light rail into town I noticed a lot of houses with swamp coolers on the rooftops (usually on a platform on the rear slope of the roof), but an even larger number where the swamp cooler had apparently been replaced by a regular AC, on the same platform. Not the most efficient place to put an AC condenser, but I suppose it was the path of least resistance.Presumably that would be a last-gasp option here -- put the unit on the roof.
I don't think a roof-mounted option would fly.
Jocelyn
Living the desert Southwest, a swamp cooler is very useful. Temperature was 115 today, with the swamp cooler getting it down to 85 inside. As for earthquakes, the swamp cooler is mainly a big metal box with very little inside of it. Usually about 3 inches of water, a big paper pad and a squrrel cage fan with motor. Turning off the water pump makes it a whole house fan that blows rather than sucks the air through the house.
Also have the Tamarack HV1000.
Quiet, and those sealing doors are great. Easy to install.
Much of the advantage of a whole house fan comes not from the air volume moved, but from blowing the heat out of the attic space. Otherwise the trapped heat will radiate down on you for many hours after sunset.
Thanks much. I'll have to have my husband look into this. Sounds like it could be a big help.
Jocelyn
I agree with your previous correspondent, csnow. The most important thing in most homes is to get the heat out of the attic in order for the captive heat in the house to rise out of the top floor.
I live in a two story house that was heated until about ten years ago with an electric furnance heat pump that also switched to an air conditioner during the summer. When we switched to gas, we kept the heat pump for an airconditioner but it is not powerful enough to cool the second floor during the hot muggy summers in Ottawa. We have over a foot of blown insulation on top of fibreglass insulation and that really keeps the heat locked in the second floor even with the windows open.
We installed an exhaust fan in the roof that within minutes lowered the attic tempurature to a comfortable level. By keeping the attic door open in the stairwell, the house heat soon rose from the second floor and the house was unbelievably cool even during the heat wave.
The air conditioner was on so little that I had to jump start it in order to keep the basement dry.
The only problem we had was the fibre glass insulation eventually clogs the motor burning it out. We have looked at the Tamarack fans but their distribution in Canada is limited.
Thanks much. I think we will be looking into this.
Jocelyn
I'm also in the Bay area (San Jose) and don't have AC or a "whole house" fan. I do, however, have double pane, low e, windows and ceiling fans in almost every room.
We open the house up at night, then close it up in the morning and it stays reasonably cool all day. Last Sunday afternoon, the outside temperature was in the high 90's and it was 82* inside the house.
When I was growing up in MO, my parents had an attic fan in the hall near the bedrooms. It was on a mechanical timer and did a good job of cooling the bedrooms at night.