Quiet Cool Whole House Fans - Installs in your attic Now, I'm not a handy person, so I'm going to have to hire someone to install, but any opinions on the three modes of home cooling as to reduce AC use?
Are you in an older or newer home? Approximately when was it built? These work great to draw cool air in if the outside temp is decent and there is little humidity. I've installed probably 50-100 similar ones. The only concern is adequate attic venting. If the attic venting isnt adequate and you run the system on humid days they can create condensation issues. A way around that is to vent the exhaust portion of the fan right out of the soffit or end walls themselves. But both of those require siding and or soffit changes which can be time consuming and expensive
My home is 10 years old. It's 2 stories. I had an electrician go up there and he says that there are vents in the roof(gable?) already in place. He doesn't have to put a hole in the roof. He says the install for an attic fan will take 45 minutes. Equipment, labor, taxes $345. You've done the quietcoolfan? or the attic fan? With the quietcoolfan, I like how each room can control a fan or that really of any use?
Ive done different versions of the quietcool fans. As to the each room controlling depending on temps thats a good thing. $345 bucks is a great price for an install I used to charge anywhere from 400-800 for those depending on time and material. I have talked to a few of the people I have installed them for. If its under 77degrees and not humid outside they love them. Above that with any significant humidity the dont notice much difference
At least consider, before you drop a few hundred in a energy burning fan system, might you be better off in the long run, doing a combination of passive venting (adding intake and exhaust vents) and perhaps more importantly, ADDING attic insulation. A higher R-value of attic insulation will reduce the cooling load significantly and will reduce the heating load as well. There is almost no more cost effective energy saving dollar to spend than that of attic insulation. Blow in from a insulation contractor is very inexpensive, way cheaper than buying batts from the big box store. You do have to watch out however not to cover low intake (soffit vents with insulation, reducing their effectiveness to near zero. Simple Insulation baffles are easy (sort of) to install to keep the blow in from covering the soffit vents. Icarus PS A well vented attic should create it's own draft, heated air exiting the higher vents, drawing air in the lower vents. Add in some help for the wind and you may not need fans at all.
While I agree with Icarus's statement for the most part. Being a 10 year old home his attic should be insulated to an R38 already and adequately ventilated. Anything over an R40 in the attic is a waste IMO
I don't see any EnergyStar ratings for these fans yet. Only ceiling fans and small fans (bathroom, utility room, and range hoods) are rated at this time. Dave -- do you recall what the power ratings were on the fans you installed? If they could be somewhat similar to the efficient ceiling fans, drawing ~10W on a low setting and 20-30W on medium, then they wouldn't be energy hogs at all. The product in the OP draws 150W, though that would be the highest setting. It doesn't mention any lower settings. At first glance, I'd guess this is not one of the modern crop of high efficiency devices, though even that power is much better than any AC unit. But whole house fans are not going to achieve the CFM/watt performance of unducted ceiling fans, so I don't have a good basis for comparison.
Depending on where the house is located, I wouldn't bet that the ceiling has ~R-40 as it stands being ~10 years old. I agree that there is some diminishing returns regarding insulation, but the simple formula is double the R-value and you cut the heat gain/loss by a factor of two. Now if you have an R-1 and you loose/gain 10,000 btus/sq ft, and you go to R-40 you reduce that to 250 BTU, going to R-80 drops that to 125 BTUs. That said, find out what you have, and it is still quite cheap to do. The difference between heat gain versus heat loss, is that all insulation values are based on the DIFFERENCE in temperature between spaces. With a heating load you might have a Delta of 70f with OAT of 0f and a heated envelope at 70f. Cooling load, might have a Delta T of 70f as well, 70f cooled space, and 140f attic temps. The difference is that you can actively and passively cool the attic, but not warm it. As for fan efficiency, you're right, a paddle fan moves tons of air with comparatively small wattage. Any sort of ducted fan probably isn't going to move nearly as much air per watt. Icarus
Being 10 years old depending on the area of the country the OP lives in yeah I gaurentee its an r 38 at a minimum. Going to an R80 LMAO. Two reasons that wont work. nearly impossible to have adequate attic venting then being most important. Without adequate attic venting and that level of insulation you essentially created a rain shower and mold issues up there
I agree, going to R-80 is silly, I just used it to illustrate the diminishing returns. That said, I have now idea what the California energy code requirement was ten years ago. It only takes a minute to climb up and check, and if it isn't near R-38-40 and up grade is suggested. Icarus
*Not to intending to steal Burritos thread*, but I've been strongly considering a whole house fan and this thread has already provided some good information. Is there an age of the house (era) where the vents in attic may not be adequate? We have a ranch style house (built ~ 1970) with the screened openings in the lower part of the roof (gables?). Similar to what my parent's 1950's vintage split level has. It also has an attic fan.
Burritos, R-value is demonstrable standard for insulation. The "R" standard is a resistance to heat flow. It is the inverse of the U-Value of any given component. The U-value measures heat loss per square foot per degree F temperature difference between one side and the other. A lower U value translates to a Higher R value. Most modern codes require ~R40 (40 times less heat loss/heat gain than R-1, like a single pane of glass~) This equates to ~12" of fiberglass. When you buy insulation, the package will show the R-value on the package. Keep in mind, that insulation works (generally) because it traps air. People make the mistake of buying R 11 (designed for a 2X4 wall) and thinking they can double their insulation value so they stuff in 2 layers. This not only doesn't double the R-value but in all probability reduces it below R-11 because it has lost it's ability to trap air because it is compressed. Icarus
Depending on where you are, a 70's house PROBABLY has terrible attic venting. With an good vapor barrier, the code formula (is I recall properly!) is a ratio of ~1/150. So that if you have 150 square feet of attic, you should have a minimum of 1 square foot of venting, balanced between low intake vents and higher exhaust vents. If you live in a 70's ranch, I would seriously consider adding continuous ridge vents at best, or a series of high roof vents. The problem with relying on gable vents is that they cross vent pretty well, but they don't draw air in from the low very well. Venting serves two purposes depending on climate. One is to allow excess solar heat to vent from the attic. The second and perhaps more importantly, it serves to vent moisture that condenses from inside the living space. That is why a good vapor barrier is essential. In lieu of adding a layer of plastic (on the conditioned side, under the insulation) a Perm rated paint on the ceiling can do a pretty good job as a vapor barrier. Vapor barrier become way more important as climate become more extreme. In very cold climes, a tiny leak in the vapor barrier can lead to huge moisture issues in the attic. Consider this. If your indoor relative humidity is ~50% and the temp is +70f, if the air in the house were to infiltrate to the attic, where temps can be ( in my part of the world) -40, the capacity of that air to absorb the moisture is nearly zero forcing the moisture to condense on any surface causing huge frost build up. When the temperature rises, the frost melts, and the liquid water can cause very significant damage. I don't have a lot of experience with the reverse, that is hot humid outside air, meeting cool dry indoor air. The difference here is the Delta is much closer. Say 100f outside/70 inside, leaving a ~30 Dt, rather than the ~110F Dt in the cold scenario. Icarus
