Replies

1. 
   Carlos_Bonilla | May 17, 1999 10:01pm | #1

   *
   Mike--you may also want to consider an override switch which would let you turn the fan on when desired. I've never had an ice dam problem on my house, even when my neighbors have, because I turn that fan on whenever there's snow on the roof to keep the attic nice and cold.

   Carlos

1. 
   David_Thomas | May 18, 1999 07:02am | #2

   *Or wire a single pole, triple throw pole (SPTT) switch for Hand-Off-Auto like is done for process equipment. Hand is always on. Off is always off. Auto runs thru whatever thermostat and/or timers you have selected. So, in your absence, the system can be as smart as you can make it with timers, thermostats, humidistats, differential temperature sensors, etc. But when you're around your can play with it, optimize it, and learn more about its performance. -David

1. 
   Fanny_Bryce | May 19, 1999 01:05am | #3

   *"thermostat will set the fan on mid day thereby dragging the heat of the afternoon into the house negating what benefits might accrue"Wouldn't this scenario be truer? During mid-day temp of 95 degrees, the attic might reach 120 degrees. So dragging 95 degree air thru the hotter attic would cool it down a bit, n'est pas?

1. 
   Gene_Leger_ | May 22, 1999 12:33am | #4

   *Michael. My reading of your post says you are not going to use a whole house fan. For starters consider the following: (a) Because the dominant heat transfer mechanism in an attic is radiation,this heat cannot be "flushed" out of the attic; (b) If the ceiling below the attic (attic floor), is leaky these fans will suck heat out of the rooms below, thus making them cooler. However, it will also suck heat out of the house in the winter time;(c)testing in realhouse attics show that insulation is a less costly more effective way to reduce heat movement from the attic to the rooms below. Cellulose is the insulation of choicebecause it is less transparent tt radiation than low desnity fiberglass. Have you considered the possible negative consequences of these fans especially with a house full of gas appliances? GeneL.

1. 
   JT_ | May 22, 1999 03:36am | #5

   *Fanny, both statments are true. You will cool the attic a bit at the expense of heating up your house. Bad trade. When most people think about this scenario, they immagine that all the air exhausted by the fan will be made up for by outside air from other vents, when in reality, unless you've air-sealed the attic floor, much of the make-up air will come from the house; the house will then need make-up air from outside.

2. 
   Mike_Mahan | May 22, 1999 06:35am | #6

   *One time on an electrical job I had to wire an attic exhaust fan. The owner would not pay me because of the suposed defect in the electrical installation--the fan would not shut off. The real defect--the fan would never cool the attic enough for the thermostat to turn it off. The client was a lawyer so I never did get paid. The moral: Don't work for lawyers.

3. 
   The_Tennis_Court_Builder_...on_t | May 22, 1999 06:12pm | #7

   *Lawyers pay cash up front and sign a no arguements clause in blood.....Near the stream and glad I don't depend on them often,J

4. 
   RJT_ | May 31, 1999 08:43am | #8

   *are whole house fans a bad idea?

5. 
   Gene_Leger_ | May 31, 1999 08:49pm | #9

   *RJT. see "Drawbacks of Powered Attic Ventilators"in Nov/Dec 1995 issue of Home ?Energy. IT may be downloadbale from the web site, homeenergy. GeneL

6. 
   Bill_Conner | Jun 01, 1999 04:53am | #10

   *RJT - are you asking about fans to ventilate the attic - as Gene seems to respond to - or using a fan to exhaust warm air from the living spaces and draw outside air in?

7. 
   andrew_d | Jun 01, 1999 05:17am | #11

   *Now, now, this goes in the same class as stereotypes about contractors, who are all a bunch of thieving crooks ... if you see what i mean ... :)

8. 
   RJT_ | Jun 01, 1999 08:00am | #12

   *Whole house fans are used to suck air thru the house with the idea of exhausting the hot air from the attic intaking from the interior of the house. I ran a gable fan last year and it never turned off and the attic space never got any cooler, it's intake was thru soffit vents. Our house stays the coolest in hot weather by closing all the windows, but I see the way they designed houses in the south with the chimney effect, which to me sounds a passive version of a whole house fan and wonder if it'd work.I just tried to look up http://www.homeenergy.com and there ain't none.

9. 
   Bill_Conner | Jun 02, 1999 06:50am | #13

   *www.homeenergy.org

10. 
    Bill_Conner | Jun 02, 1999 07:32am | #14

    *Also, try http://oikos.com/esb/40/tamarack.html for a good whole house fan.

11. 
    Harvanators | Jul 10, 1999 12:11am | #15

    *Could it be possible to vent out the attic and the craw space at the same time? Have a attic fan that draws cooler air form the craw space trough and type of tubing into the attic. Not sure if it would help kill two birds with one stone. Would it in a sense dry the basement by making it warmer (end to condensation) and cool off the attic by adding cooler air? What do you think of this? The Harv

12. 
    andrew_d | Jul 10, 1999 12:04pm | #16

    *Venting crawl space = bad. How is your house coming??

13. 
    Barry_Miller | Jul 13, 1999 02:09am | #17

    *Who here has first-hand whole house fan experiences they can share? The way I see them, they're big thirty-six inch warehouse-type fans that make a great racket as they consume 550 watts sucking big buckets of air into an attic that probably hasn't sufficient ventilation to exhaust it. Wouldn't this work as well on a wall or with a tube through the attic to the roof, like the Fantech exhaust fan? The Tamarack 1000 is definitely smaller, with far fewer CFM than the big monsters, but no joists or truss chords are cut to install it, it takes only about 80 watts, and it's just three sones loud. I'd guess you'd get only a mild breeze from it, like a ceiling fan on medium speed, but you wouldn't have to worry about foo-foo dogs and toddlers getting sucked up into the attic.

14. 
    Rebeccah_ | Jul 15, 1999 01:14am | #18

    *When I was in high school, my dad installed a whole-house fan in the ceiling at the top of the stairs of our split-level. We used it in the evenings in summer, instead of the air conditioning, when the air outside was cool. It had a manual switch on the wall. It wasn't intended to cool the attic, just the house; and in that respect it probably wouldn't have made any difference if it had been ducted to bypass the attic entirely. This was in pre-airtight house construction days, but we opened the windows anyway, and there was a barely perceptible breeze throughout the house. The main limitation as a cooling method was it did not control the humidity. My father was convinced it saved money over running the air conditioner all the time.

15. 
    Harvanators | Jul 15, 1999 02:01am | #19

    *Hello I would like to share what was done over my brothers new home. There was a fan on one of the gable ends. We noticed that when he turned on the attic fan it never shut off. Second the vents on it’s soffits and on the other gable ends was not sufficient enough(way to small, could neither make them bigger do to space restriction). The attic is not insulated so it was drawing air through ever nook and cranny. The electrical outlet’s ports were collecting dust almost. So observing this he decided to put in a ridge vents across the whole span. It did achieve it’s purpose. The fan had run from 10:30 AM to around 11:00 PM set at around 120 or 130 I forget what one. Now it shuts off earlier in the evening set at 85. He just put in humidity setting as well. To make in more specialized. Well The attic is cooler, meaning less heat cooking over his head. A fan can work to cool off the attic. Thanks The Harvs

2. 
   Michael_Milbrath | Jul 15, 1999 02:01am | #20

   *
   So, I want to revisit this discussion before I pu
   out any money. When last I asked about the
   benefits or lack therof of installing gable vent
   fans, the consensus seemed to be they were a mixed
   blessing as the thermostat will set the fan on mid
   day thereby dragging the heat of the afternoon
   into the house negating what benefits might
   accrue.
   However, What if I were to disconnect the fan from
   the thermostat and connect it instead to a switch
   on the 1st floor. I really only need to cool the
   house in the early evening when the indoor temp is
   80 degrees plus and outside its 65 degrees. Will
   this work?
   I welcome comments. Mike