Attic fan, yes or no?

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Gets super hot from June to September in Oklahoma. AC cycles on and off all the time with the t-stat at 76. We've installed new windows and attic insulation, which has helped a lot. Solid core entry doors as well. 1700 sq ft ranch style house built in 1980. Thinking about a gable mounted fan to exhaust heat from the attic.

  8 answers
  • Lisa Lee Bernier Lisa Lee Bernier on Jul 15, 2017
    yes i would use a fan

  • I have a tiny 1200 sq. ft. house and have 2 attic fans. Had them installed when I replaced my roof and insulation. LOVE them! Mine are set so that when it reaches 90° in the attic they automatically turn on. Helps conserve energy and the a/c will run better and not as hard, plus will make your roof last longer too. I also paid extra to have a switch installed so I can turn on and off from inside the house as needed. 76 would be a luxury, energy costs high here have mine set at 80. My vote is yes, worth the investment.
  • Molly Anmar Molly Anmar on Jul 15, 2017
    If a house has insulation on the attic floor, there isn’t any evidence to support the idea that attic ventilation will reduce your air conditioning bills, and attic ventilation sometimes causes problems.

    Jeff Gordon, in his presentation on attic ventilation, wrote, “Cooling season energy savings? Well, we tried to measure energy use, but this did not work very well. … Basically, [any savings are] lost in the noise.” Gordon reported that research has shown that “Attic ventilation is not an effective energy conservation procedure for houses with more than 6.5 inches of attic insulation.”

    Summing up, Gordon reported, “Venting will reduce the temperature in an open attic. The difference in attic temperature between a vented an unvented attic, with R-30 at the ceiling, translates into minuscule [cooling energy] savings. No savings have ever been measured. … In mixed climates, savings from delta T must be balanced by losses from delta T in the winter. In cold climates, this is clearly a net loser.”

    In some homes, the HVAC equipment or ductwork is located in a vented attic. This is a terrible practice, of course. Ventilating this type of attic doesn’t solve the problems associated with locating equipment and ductwork outside of the home’s thermal envelope. As building scientist Joseph Lstiburek explains, “In a situation where mechanical systems or ductwork has to be in the attic space or when there are lots of penetrations in the ceiling below the attic, it’s best to bring the entire attic area inside the thermal envelope. This way, it’s not as big a deal if the ceiling leaks air or if the ducts are leaky and uninsulated.”

    It would probably be best for you to consult with a local roofing specialist. A phone call would probably be free.


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  • Sandy Sandy on Jul 15, 2017
    If you put in an attic fan, please make sure to that you have an automatic shut off in case of a fire. If you were to gave a fire in your house, the fan would help it spread. I'm not sure how the shut offs work, but I'm sure you could ask your attic fan pro.
  • Nancy Wilson Nancy Wilson on Jul 15, 2017
    I had a heat shield installed in addition to the attic insulation. It looked like aluminum foil with pinholes. It allowed the heat to reflect back to the roof while preventing moisture build up. I also had thermostatically controlled fans installed. Not only did this save on the heat, AC usage and costs, but allowed me to use the attic for storage without worry. I think this is available at Home Depot or Lowes.
  • Eroque022810 Eroque022810 on Jul 15, 2017
    I had a home contracted tell me that once it gets to desired temperature to put it on fan not keep it on auto. I have been doing this and it's helped quite a bit. We did everything you have done as well and we have a home fan but that helps a little I mainly you use it to remove any cooking odors. We have a two story home and upstairs used to get super warm. Now house stays pretty consistent. Hope it helps. You have nothing to lose.
  • Kathy Bitzan Kathy Bitzan on Jul 15, 2017
    My sister had a huge attic fan and at night she would open her windows and turn that thing on and in 15 the whole house was cool enough to sleep. Not sure if this is the answer you were looking for, but any type of ventilation helps to rid the area of heat.

  • Laura Spivey Smarr Laura Spivey Smarr on Jul 15, 2017
    I use my attic fan mostly in spring and fall and love it. It doesn't help in hot summer weather unless I just want to air out my house for a short time. Also if you have allergies you might have a problem bringing in pollen.
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