Curious about whole house fans and how effective they really are. Open up the downstairs windows and turn on the upstairs fan.
Seems logical but my question is how much more effective are they than just sticking a $50- box fan in the DH window at the top of the stairs on hot nights?
The cfm numbers from whole house fans ive seen dont seem to compete with cfm on a cheap box fan. What am i missing?
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I'm a fan of whole house living and I'm pretty effective
.
;)
OK, enough of that.
I would be concerned about pumping all that moist air into the attic. It has to have a way to get all the way out of the house, not just above the ceiling.
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Being centrally located, they draw more evenly from the whole house, and they don't make one room with a fan a "wind tunnel". And the relatively cool air blowing through the attic has an additional cooling effect. Plus they're generally quieter than window fans.
The window fan will work, though not as well and not as conveniently.
That reminds me -- time to cover the fan for the winter.
This country will not be a permanently good place for any of us to live in unless we make it a reasonably good place for all of us to live in. --Theodore Roosevelt
If you're in a humid environment, they're bad. Let's say its been 90 and humid all day; you're inside with the AC on at 75. Nighttime comes, temp drops to 75; open the windows and crank up the fan.
BUT - the 75 degree air outside is almost fully saturated (close to its dew point); the inside air at 75 is dry because your AC has been working hard all day to de-humidify it.
Next morning, you've got to spend electricity to pull all that moisture out of the air, your fabrics, everything. You can make the calculation that your AC may spend more energy on dehumidification than on cooling.
There was a period here in the SE when they were popular; now they are not recommended.
Forrest - actually an engineer
Yo Forrest,
I have a rope lite, and half of it quit. what gives?Spheramid Enterprises Architectural Woodworks
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Use the other half!
No - really - is it LED? I'm guessing there are multiple paralled strings of serially-attached chips to get the forward voltage required. How many went out?
Forrest
Yeah, a rubbery rope with the lil lites inside, it quit about the middle. I use it for the stairway light path inside. Strange to me, but I'm not sure if they are LRDs, kinda cheap for that.Spheramid Enterprises Architectural Woodworks
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PROUD MEMBER OF THE " I ROCKED WITH REZ" CLUB
A lot of the LED (and even non-LED) ropes work just like the old-style Xmas lites -- they run off two (or more) circuits if they would be too long for the thin wire used to carry the current for the whole strand.
Yeah, they're getting cheaper. Prolly not worth the agravation to fix.
Oh, and ALWAYS use a pizza stone. Even if you stoop to using the frozen imitations of that culinary delight. ;-)Mike HennessyPittsburgh, PAEverything fits, until you put glue on it.
I just went and checked, the whole dang thing is out now, time for new. It's been on 24/7 for a year.So how HOT does the stone need to be? The wife made a huge mess on the stone, and I think the crust just fell apart semi cooked, while top was burning. It's not a REAL stone, it's a 1" thick marble tile about 16" SQ.Spheramid Enterprises Architectural Woodworks
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In the restaurant we cooked pizza in a wood-fired brick oven; we started the fire at about 9 in the morning (from the coals of last night's fire, usually) for the lunch crowd. Burned about ten or twelve 16" logs down to coals at full draft, then spread the coals 4-6" thick over the cooking area. When it came time to bake a pizza, we broomed a spot clean and slid the pie onto it.
So, how hot is that, LOL?
For your oven stone, usually they have to be about 450ºF to prevent sticking. Which means you gotta crank the t-stat on the oven up to 450 and preheat the stone for a good 20-30 min. Also, there has to be a decent amount of flour on the bottom of the crust. Not wads, of course, but a good dusting.
If yer using frozen, you have to put it on the stone frozen. Don't thaw it out first.
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
She didn't preheat enough.Ya'd think that would be a trait for a Sicilian woman.
Now she swears she'll never use it again, and it's my fault.Spheramid Enterprises Architectural Woodworks
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Now she swears she'll never use it again, and it's my fault.
Well, of course it's yer fault. Yer the pointer and she's the setter.
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
A stone is a stone is a stone, to some extent. A good stone is a bit porous so it'll let the dough steam -- helps it crisp up the bottom and keep it from getting soggy. It retains a bunch of heat -- kinda like the copper head of a soldering iron.
Plain ol' firebrick works great. If you have any around you can just store 'em on the bottom of the oven or the lowest shelf. This has the added benefit of evening out the temp profile of the oven, but has the disadvantage of making it slower to preheat and/or cool down. But marble should be OK too, but I'd use it rough side up.
Sounds like DW didn't pre-heat the stone enough. For pizza, you need to preheat for a good while, since the oven will heat a lot faster than the stone. I get the floor of my wood-fired oven up to around 700° for pizza and the walls are closer to 900°. That gets 'er done in about 90 seconds. For a normal oven, I'd crank it as high as it'll go and let it preheat about 20 - 25 minutes. If you have an IR thermometer, you could check the stone with that to make sure it's hot before you load the oven. (I've even heard of some who heat the oven & stone on self-cleaning mode for higher temps.) For frozen, you may have to experiment a bit, but I'd probably turn the oven down after the stone was around 450° to whatever baking temp is recommended by the manufacturer -- wouldn't want to void the warranty! ;-)
As for the mess on the stone, it'll just burn off next time you heat it. That, or let the dog at it -- he'll clean it like new.
And tell me you didn't have runny pizza for T-day! Gasp! ;-)Mike HennessyPittsburgh, PAEverything fits, until you put glue on it.
Thats exactly what I told her. HOT, HOT, HOT.No, I set the mess outside for a few weeks and it's all gone off the stone now. This was awhile ago.we make some killer strombolis and Calzones, all fresh made dough, and have a funny pizza cooker that rotates.I get the 10 for 10bucks party pizzas and nuke em for a quick snack, fold in half with lotsa extra cheese and garlic and hot peppers, like a pizza taco.She sometimes likes the Red Baron type or "Gormet" frozed when she don't feel like making from scratch, thats what she ruined ( I ate it anyway) and got in a tiff about my stone idea.Always my fault. (G)
Oh, its gas stove, so I will experiment next time.Thanks.Spheramid Enterprises Architectural Woodworks
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"Thats exactly what I told her. HOT, HOT, HOT."Yeah, if it's not hot enough, it just keeps the bottom cool while the top burns. Kinda like soldering a pipe with water in it.
"No, I set the mess outside for a few weeks and it's all gone off the stone now. "Racoons, dogs -- all the same.
As for the frozen stuff, we just make 8 or 10 extra shells when we make it and prebake 'em a bit. Freeze them and top 'em with your own stuff when the mood strikes. Come to think, we're runnin' low. Time to bake.
"Always my fault. (G)"Can't be -- always MY fault.
That's what I'm told, anyways.
Sad thing is, she's usually right.
"Oh, its gas stove, so I will experiment next time.Just peg the knob, let it preheat 20-25 mins, and yer good to go.Mike HennessyPittsburgh, PAEverything fits, until you put glue on it.
This is weird, she went out to get us some cold medicine, we both got it bad. Just called and said to preheat for....Frozen Pizza!So I just stuck the stone in and set it at 455. She'll be here in about 20.
I'll report my findings..LOLSpheramid Enterprises Architectural Woodworks
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We've got a (unglazed) ceramic "stone". Probably 1/4" thick, mostly. (It has feet molded into the bottom.) Works fine for us -- I think we warm it up 15 minutes or so, or just put it in the cold oven and wait until the oven is warmed up, plus maybe 5 minutes more.
This country will not be a permanently good place for any of us to live in unless we make it a reasonably good place for all of us to live in. --Theodore Roosevelt
I have 12V LEDs in the back yard and I've fixed the wires when they broke.
They are small so put on your close up glasses.
I have tried to fix real small wires and I guess they were just to small.
I think the rope lights have real small wires and the insulation (clear part) is so thick it would be a pain. "There are three kinds of men: The one that learns by reading, the few who learn by observation and the rest of them have to pee on the electric fence for themselves."Will Rogers
There was a period here in the SE when they were popular; now they are not recommended.
I would suspect that the period during which whole house fans were popular down your way was prior to the advent of universal AC. Certainly that was the case in New York in the 50s and 60s. It doesn't get as hot there as Jawjah, but it does get up to 90 on a regular basis and quite humid. Look at photos of people sleeping on the roofs of tenemants in NYC in the 1920s, or blowing a small electric fan across a 50# block of ice in the kitchen.
say its been 90 and humid all day; you're inside with the AC on at 75. Nighttime comes, temp drops to 75; open the windows and crank up the fan.
I can't imagine why anyone would try to combine a whole house fan with central AC; okay maybe you'd save a few bucks on electricity not running the HVAC system at night, but few people accustomed to bone-dry conditioned air are gonna feel comfortable suddenly changing over to ambient air with the normal amount of humidity in it.
To use a whole house fan to its best effect, the house pretty much needs to be buttoned up tight and the shades drawn during the hot part of the day; then, when the sun goes down and the temps drop, you open a couple of windows in the basement, and crank up the fan. It'll pull in the cooler night air, and the thermal mass of the concrete walls in the basement will cool it further before that air is pulled up the stairwells to the upper floors. It works quite well, unless, of course, you're sitting under a big, fat, humid, hot low-pressure system all night....
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
I agree - but I've worked on tons of little houses in my area from the 50s and 60s (originally built with central air) that have now-unused whole house fan louvers in the hallway ceiling.
Speaking of sleeping on rooftops - DW and I are designing our next addition - a sleeping porch over this flat roofed wing that abuts our second-floor bedroom (left window). Think completely screened walls, like a Florida room, open to the rafters, several screened gables, ceiling fans, generous overhangs, and some skylights. Might even use galvanized steel framing, for the visual lightness and shininess at night.
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Forrest
Oh, yeah, sounds great. Oughta get you up above snake level, too.... ;0)
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
whole house fans can be detrimental to your health!!!!
When the costumer called that the gas company had shot the water heater down because there was no venting on the chimney and they suspected that there was a blockage in the chimney, and Carbon Monoxide was spilling into the home and tripping the smoke alarm. The chimney was clear with no obstructions we asked the customer if they had a whole house fan and if it was running? the answer is always yes! The fan sucks the ambient air from the house including the air from outside through the chimney and out the water heater diverter into the home. The OH has two choices the water heater of the Whole house fan.
Nothing wrong with the fan, but the HO sounds like a prime candidate for a Darwin Award.
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
I'm convinced that ducted whole house fans work very well, when installed in a central location. I'm also convinced that cooling the human body by evaporation provides the most relief and is better for its health.
I trimmed a house with that system one hot summer and it made a big difference in my comfort. The fan was placed in the ceiling of the central upstairs hallway. It was ducted out the nearest gable end.
The down stairs double hung windows were cracked open a few inches at the bottom. When the fan was running there was a continuous flow of cooling air passing by.
Your location in So. Oregon is probably dry enough to allow you to use the whole house fan that exhausts into the attic and then out through the gable vents.
But your Q seems to indicate that you'd prefer to use the cheaper and simpler window fan if it would be effective.
I think the window fan will work--even two of them located right would be far cheaper and easier than the whole house fan. And, of course, you could always go for the whole house fan later if you're not happy with the window fans.
Keep in mind that what you will be doing is de-pressurizing the whole house when the fans are exhausting air. Any windows that you open will allow air in, so you can control the air path to a certain degree by which windows are opened.
Safety: If you have a gas water heater in the basement, it could begin backdrafting if no windows are open to allow air in. The flue of the water heater could become the opening that supplies outside air to the fans.
I am a BIG fan of whole house fans. I recommend Tamarack's fans. They have louvered insulated motorized doors that seal the fan when you turn it off. This really helps in winter but it also keeps the bugs out in summer. The big fans sold in big box stores move more air but are loud and must be covered in the winter and they let in bugs in the summer. Get the manual switch on the Tamarack, it works better than the remote. I use the fans in NC and they work great.
I use the box fan in the window method...actually, in my upstairs hallway there's a door that leads out to a deck on top of the back porch, and the screen door is sized just right for two box fans situated one on top of the other. With a couple windows opened downstairs, they do a real nice job of pulling air through the house. The box fans are good quality ones I bought at Grainger - they seem to pull more air and last a lot longer than the flimsy ones you'll find at Home Depot.
FWIW, a few times I've informally tested installations by putting a draft gauge in a furnace or water heater flue in a basement, all windows and doors closed, turning on a whole house fan, and opening a sliding door in stages to find the point where the neg pressure created by the WH fan stops drawing air down the flue.
Lots of variations of course, but as a general rule, a sliding door has to be about 15-20" open before the neg pressure created but the who;e house fans stops creating flue back drafting.
I don'r think an ordinary box fan would create anywhere near the air flow that a whole house fan does, not to mention the location point that several have raised.
"Man's capacity for justice makes democracy possible, but man's inclination to injustice makes democracy necessary."
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I think what you are trying to re-invent is the 'economiser.'
Found on nicer AC units, they monitor the outside air temp. When the night cools off, the unit stops 'conditioning,' and just brings in the fresh outside air.
Ideally the unit would monitor humidity as well, and calculate the relative cost of cooling the inside air vs dehumidifying the outside air.
This country will not be a permanently good place for any of us to live in unless we make it a reasonably good place for all of us to live in. --Theodore Roosevelt
For all I know, they do ... though to what extent - energy cost is a variable - I can't say.
A proper AC unit will not simply cool the inside air; you need a certain amount of air exchange.
Now that I think about it, the unit's I've seen also heat the air in winter, so they have air intake ductwork. True, these were commercial roof-top units, but residential units are usually tied into the furnace ductwork and have a similar ability.
I've seen the commercial units, but never seen a true residential "economizer", whether "smart" or not.
This country will not be a permanently good place for any of us to live in unless we make it a reasonably good place for all of us to live in. --Theodore Roosevelt
Lots of good points here - based on my experience, part of the appeal of whole house fans depends on what you want to experience.
I have an early 50's ranch with both central AC and a humongous 30" fan over louvers in the central hall - didn't work when we moved in, but I REMEMBER how great they were when I was a kid, so I immediately renovated the thing and set it in motion.
Yep, gotta open windows first or the backdraft down the fireplace chimney and down the hot water flu are truly educational.
Yep, in comes humidity and pollen with all that fresh air. However, in comes all that fresh air! The whole house just smells better after an evening of whole house fan.
And, that annoying "thrum, thrum, thrum" of the central AC is OFF for 12 hours or so.
I finally modified mine with a more modern two-speed motor so that we didn't experience a hurricane through the bedroom window when we go to bed at night and, for paranoia's sake, close and lock all the other doors and windows.
It's all in what you like.
I Still have to devise a practical way to seal the thing in the winter so that it isn't a 900 square inch open heat duct to the outside via the attic during the winter months. Plus I had to box it in so's we could add insulation to the attic and not have it foul the fan. Maybe I'll put a couple of foam doors on it like the more modern versions - or ????
Mike D
I built a box out of corrugate lawn signs (I have a garage full) and foil duct tape. Sits over the fan and seals it pretty well. In the spring just turn on the fan and it blows off.
This country will not be a permanently good place for any of us to live in unless we make it a reasonably good place for all of us to live in. --Theodore Roosevelt
I have the Tamarack, it works great, just way too loud. if you buy a whf, check the noise rating.
Edited 11/30/2009 10:15 pm ET by shellbuilder
That's the unit with the four small fans? Yeah, I was wondering if that was kinda noisy. A regular whole house fan runs at a lower RPM (especially if you turn the speed control down, which is normal for us), so the noise is a lower pitch and less annoying.And, if there's room in the attic, one can elevate the fan 2-3 feet above the ceiling, line the resulting box with sound absorbing material, and achieve an even quieter setup.
This country will not be a permanently good place for any of us to live in unless we make it a reasonably good place for all of us to live in. --Theodore Roosevelt
It's tolerable on low speed but not effective on low speed. I like the remote, you really need the remote to turn the thing down to hear tv or whatever.
Edited 11/30/2009 10:18 pm ET by shellbuilder
It depends on your climate, especially humidity. I've been using cheap box fans for a while, but plan to go with a whole house fan when we get a little money ahead.
Here in Southern California, moisture isn't a problem. In the summer, we can quickly replace the 120 degree air in the house with 80 degree air when we get home, and later in the evening it goes down to about 70. (Actually it hasn't been all that hot the last few summers -- Al Gore must be slacking off....) On winter mornings, we can replace the 50 degree air with 70 degree air, and sometimes up into the 80's in the late afternoon, if there's a Santa Ana.
-- J.S.
I installed a WHF from Tamarack in my row house in DC. Wrong location for one, I know most will think, and I had begun to think myself. But I used it pretty consistently this fall, probably 2 months or so, when the humidity and nighttime temperatures began to drop. I really like the fresh air aspect of it (though you can argue that in this city there is no such thing), and it really doesn't make all that much noise even though it's in the roof directly above the mbr. It is barely large enough for the house as per Tamarack tech support, and it's not made to create a draft, but the difference in air quality in the house is considerable.
Of course, you have to use it right. I button everything up during the day, all windows closed, etc, then as soon as I get home, I'll open a couple windows downstairs and turn the fan on. It'll take an hour or so before I notice any difference, but it is noticeable.
Ca coute tres cher, unfortunately, but since I've a hot roof, it was the only option if I wanted one. We'll see how it plays out in the spring, but if I can get 2-3 months usage from it a year, it will pay back itself in a couple of years, which isn't too shabby.
Z