I live in a mediterranean climate in Southwestern Oregon where average high temperatures during the peak of summer are 90 degrees, and average lows are 58. Our house is on a southwestern facing slope, and it has limited shade. Thus, it’s fully exposed to the sun, and the air conditioning system needs to work overtime during late spring, summer, and early fall to keep the house at a comfortable temperature.

At night, I have turned off the central air, opened the windows, and hoped that the cool air from outside would transfer to the inside. However, as I’ve experienced in other houses, only a few degrees of cooling occurs using this method–and I’ve had many nights with restless sleep because of a warm bedroom. This is because simply leaving the windows open does not actively cool the thermal mass of the house nor distribute cool air throughout the house.  Therefore, once the sun rises, it doesn’t take long before the central air needs to be turned on again.  Using the central air overnight is certainly an option to keep the house cool overnight, but the energy used to do this is significant.

I’m not the “greenest” person on the block, but I do like to be aware of and explore environmentally friendly options for most of our purchases. So I set out to learn more about ways to keep our house cool in an energy-efficient manner. First, I investigated purchasing solar panels that would power our central air, ideal because of our ample exposure to the sun. I spoke to a local resident that has solar panels, and they had very favorable reviews. However, when I did the math, it was going to be too costly of an initial investment unless we planned to live in our house for 30 years, which we don’t. Additionally, some of the tax credits associated with solar panels have gone the way of the dinosaur. The idea still intrigues me, and I hope to be able to invest in solar panels in the future. It just makes sense. The second option I explored was a whole house fan. Our neighbors told us about their whole house fan which cools their house rapidly in the evenings once temperatures drop into the 70s. They did mention that the fan, although only on for 5 or 10 minutes to cool the house off, was very loud.

So, to make a long story short, I weighed the options and decided to get a quiet, energy-efficient whole house fan installed. I had an Airscape 2.5e whole house fan installed in my 2000 square foot house. I talked to a few people who had these specific energy-efficient fans installed to get a decent idea that they would do the job. The concept behind these newer fans is that the user leaves them on all night, allowing the structure of the house, or thermal mass, to cool off sufficiently to maintain cool temperatures during the next day. I’ve added a post of pros and cons to the fan now that I’ve used it for a couple months. Overall, the investment was not exorbitant, I’m very pleased with the fan’s performance, and I know it’s using significantly less energy than if I just used our central air. This results in cost savings, and since energy prices will likely not be going down anytime soon, the money I save should increase year to year.

In addition to the whole house fan, I had a solar attic fan installed, which works primarily during the day to cool off the attic space, thus keeping the hottest air away from the adjacent living spaces. It uses no electricity, was recommended highly by a neighbor, and it has performed well to our knowledge.

 

7 Responses to My Whole House Fan Experience

  1. Ira Russell says:

    Great post. Excellent graphics. Wow. I would be interested in your night time noise opinion on the unit? I’m thinking of purchasing the 2.8 Kohilo for my 2200 sq-ft home in Michigan. I had a 6000 CFM that came with the house and the motor died. IT was far too noisy. Not sure why Lowes and HomeDepot sell these high output versions. They are cheap but far too noisy and overkill unless you need to cool the house off in 10 minutes and like a 10 mph gale wind flowing thru your house.

    • admin says:

      Ira,
      I’m pleased to say that the unit is VERY quiet, especially on low setting. To give you an idea of how quiet it is, we can watch TV at a normal volume in the same room as the fan, and we can’t really hear the fan at all. It’s a very low pitched sound. We use the high setting in the summer in the evening once the outside temperature dips below the house temp. This ushers in more air and can drop the temp by several degrees in an hour or two. It’s a little louder on high setting, but we can still watch TV or have a conversation near it…just have to turn up the volume or speak a little louder. And remember, these low output fans cool the structure of the house instead of just whisk in cooler air to cool the surface and us occupants. Thanks for the kind remarks. I’ll be adding a little more soon, as I’ve now had the fan for a year and am still pleased.

  2. seth says:

    What is the Square footage of your house and do you primarily use the hi or low CFM setting too cool it down during the night? What is the mass characteristic’s your your house – stick frame or cement block? I’m currently looking at Airscape and Quietcool and I have a 1600 sq ft cement block house that is well insulated.

    • admin says:

      Our house is 2000 sq ft. We primarily use the low CFM setting. We use the high setting if we want more rapid cooling in the evening. Our house is a stickframe. I don’t think it’s super well-insulated, but I know the previous owner added insulation in our attic. We also have a small solar attic fan. Let me know if you have other questions.

  3. katie says:

    I was curious to see that you have a “small solar attic fan”. What is the purpose of that? I was wondering about those and if they help with any of this. Since you mention it as an aside, it makes me think it does not contribute much to the cooling.

    • katie says:

      Just read the whole post and where you addressed the attic fan, but I’d still like to hear what you have to say about it.

      • admin says:

        Good question about the attic fan. I’m not sure how much it assists…tough to gauge for sure. All I know is it is supposed to help more during the day, exhausting the hot air outside. I think our goal was to just cool the house as much as possible, so we opted to get an attic fan to supplement the WHF. Most people I talk to that just have an attic fan say that it definitely helps. I wish I could calculate what percentage of cooling it’s responsible for, but I’m not sure how.

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