How to Look

at a House

A blog with answers
to your questions about

More blog posts about heating and air conditioning:

  1. The coils on my heat pump are covered with ice on cold mornings. What’s wrong with it?

  2. What is the SEER of my old air conditioner?

  3. How can checking the fireplace damper reduce energy bills year-round?

  4. What is the difference between the “ON” and “AUTO” settings on my thermostat?

  5. What is a “ton” of air conditioning?

  6. What is the best air conditioner for a mobile home?

  7. How do I find the right size air conditioner for my house?

  8. What is an HVAC system?

  9. What is the difference between the SEER and EER of an air conditioner?

  10. What does an ultraviolet air treatment system do?

  11. The coolant line to the outside unit of my air conditioner is frozen. What's wrong?

  12. What size air conditioner is right for my mobile home?

  13. What is the minimum SEER rating for a new air conditioner?

  14. What does the “AFUE” rating of a furnace mean?

  15. How much life is left in that air conditioner?

  16. Why is there mold around the air conditioning ducts?

  17. What is a geothermal heat pump?

  18. What is the difference between a heat pump and a cooling air conditioner?

  19. Is it alright to close the air conditioning vents in unused rooms?

  20. What is the right MERV number for my air conditioning filter?

  21. Should I move my air conditioner into the attic?

  22. What are the minimum requirements for bathroom ventilation?

  23. What is an air conditioning heat recovery system?

  24. When should I switch the thermostat to “EMERGENCY HEAT” for my heat pump air conditioner?

  25. Why does the air conditioner condensate drain line need a trap in it?

  26. What is the average lifespan of an air conditioner?

  27. How can I find out the SEER of my air conditioner?

  28. What is a jump duct?

  29. What is the purpose of the vent grille over the bedroom door?

  30. Why does an air conditioner condenser need to be level?

  31. When does the ban on R-22 air conditioning refrigerant take effect?

  32. What is a return air plenum for a furnace or air conditioning system?

  33. Why has the thermostat screen gone blank?

Welcome to our blog!
We want you to be an informed homebuyer, and each blog post is a question that we have answered for our friends and customers over the years. Hope they help you make a good choice for your next home.

    The big plus for a whole house fan, though, is low energy use, and they were a standard feature in many Gainesville homes up until the late 1960s. It may be old technology but, according to the U.S. Department of  Energy, whole house fans are also on the leading of edge of energy-efficient solutions for the 21st century. Here’s the DOE’s cost comparison to air conditioning:


Initial Cost Benefit

  1. Equipment cost for whole house fan = $150 to $350

  2. Equipment cost for window AC = $250 to $750

  3. Equipment cost for central AC = $2,000 to $4,000

Economics of Operation

  1. Operating a properly sized 2-ton air conditioner with seasonal energy efficiency of 10 in Atlanta, Georgia, costs over $250 per cooling season (1,250 hours), based on 8.5¢/kWh, or roughly 20¢ per hour of runtime.

  2. A large 18,000 Btu/h window unit air conditioner with energy efficiency (EER) of 8.8 costs more than 17¢ to operate for one hour.

  3. By contrast, a whole house fan has a motor in the 1/4 to 1/2 hp range, uses 120 to 600 watts, and costs around 1¢ to 5¢ per hour of use.

     A whole house fan can be used as the only means of cooling or to reduce  the need for air conditioning. If both methods of cooling are present, seasonal use of the whole house fan (during the spring and fall) may yield the optimum combination of comfort and cost.


    Because of the high humidity in most of Florida and the Southeast U.S. during summer months, use of a whole house fan during spring and fall make the most sense around here. So, if 1) you are buying a home with an old whole house fan that is still functional and, 2) you enjoy opening up the house during cool and moderately warm weather, then definitely keep it and use it until the high humidity days arrive.

    But a whole house fan turns from energy-saver to an energy-waster during heating and air conditioning months unless it can be sealed and insulated during those times. The metal louvers close down automatically when the fan is turned off but, because it is similar to having a jalousie window in the ceiling of the house, the lack of insulation and air leakage around the louvers creates an energy-sucking hole into the attic.

    If you don’t plan on using the fan, then we recommend removing it, repairing the ceiling and insulating the attic area above it. But, if you want to take advantage of the benefits of a whole house fan, then a cover needs to be constructed to air-seal and insulate around it. The Department of Energy has published an informative whole house fan brochure, that includes instructions and plans for building an off-season cover at the ceiling and insulated box in the attic for your fan. Click on the link below to download it as a pdf document:


    One thing you need to be careful about when using a whole house fan is backdrafting of combustion appliances, such as a gas water heater. This is a problem created when the suction created by the fan can causes combustion gases that would ordinarily go up the flue to be pulled back into the home. If your appliances don’t use room air—in other words, they are in a compartment or closet sealed from the rest of the home—it’s not a problem. Otherwise, you should consult a gas appliance professional before using your whole house fan.

    If you have a dead fan, a really noisy old one, or are considering installing a whole house fan in your home for the first time, one good resource is They can help you determine the right size fan to buy, sell you the fan, and then help you install it right with video instructions.

   By the way, if you haven’t seen a whole house fan before, the photos below show what one looks like when turned off, with the louvers closed, and also from the attic (without the off-season cover box).

While we hope you find this series of articles about home inspection helpful, they should not be considered an alternative to an actual home inspection by a local inspector. Also, construction standards vary in different parts of the country and it is possible that important issues related to your area may not be covered here.
©2015 - McGarry and Madsen Inspection.


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