This past spring and into the early summer the area that I live in (Lancaster County, PA) experienced many days where the daytime temperatures were in the 80s and the nights in the 50s and 60s. My home is well insulated, so even with the windows open, it is somewhat difficult to change the temperature inside the home drastically without fans or other devices pulling outside air in. Since our air conditioner uses approximately 3,000 to 3,500 watts of electricity when it's running and is by far our largest electricity consumer, we try not to turn it on until temperatures become unbearable. I also want to mention that our trigger for turning the AC on is somewhat heavy since we have two small children and my wife and my sleep quality is directly correlated to their sleep quality.
So, after some research we decided that we were going to install a whole house fan to help push the hot air out of our home and pull cold air in at night and early in the morning. One concern with any penetration that you make in your home is that you will also be disturbing the building envelope and the insulation that helps create that envelope. Whole house fans are usually placed through the most critical area of the building envelope, that being your attic, so by adding something that might give you some relief in temperate parts of the year, you could also be creating a gaping hole that will allow very cold air to infiltrate during very cold portions of the year and cause you to have to spend more money to heat your home. If you're able to access the attic side of a whole house fan and are able to insulate above it effectively, this may not be an issue for you. For me, accessing my attic is very difficult, and I'm not confident in my motivation to actually climb up there, through the loose fill insulation and place insulation on top of the fan in the winter months.
So, I purchased a fan that has remote control doors that are insulated to the same R-value (R-38) as the rest of my attic. When the fan turns on, the doors open. When the fan is turned off, the doors close and maintain the building envelope.
The fan that I purchased is the Tamarak HV1600 whole house fan. I installed it myself with the help of my neighbor (Rick), which was super easy since it's already sized to fit between the attic floor joists, which are 24" on center. I only had to add framing to two sides, an electrical outlet to plug the fan in, and some self adhering weather seal between the body of the fan and the floor joists. With everything in place I cut through the drywall, put the fan in place, plugged it in, installed the included fan cover and that was it.
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| Tamarak HV1600 w/R38 Insulated Doors |
The HV1600 is quite and is very effective at cooling my home down quickly and maintaining a nice breeze. The fan has two speed and the remote control works on a radio signal, so it will work anywhere within my home.
If the HV 1600 seems a bit pricey, you can find other whole house fans (models from Lowes & Home Depot) at your local home center. However you need to consider how much noise these fans can generate and how you're going to handle the insulation issue in the winter (and even the summer when the fan isn't running). You'll also need to install a control switch somewhere, ensure that you have enough air flow from your attic to the outside (gable, ridge, or soffit venting) and some of these fans are sized in such a way that you may need to do some additional framing in your attic to make them fit correctly. I can't stress the insulation and noise issues enough. Purchasing a less expensive fan may save you some money in having to run your air conditioner less, but you might end up costing yourself in increased winter heating costs and lost sleep due to high noise levels.
The easy installation, insulating, low noise, and power of the Tamarak HV1600 made this fan the right one for my home. One last important point I wanted to make is again related to the insulation we have in our home. I mentioned earlier how it's difficult to change the temperature in our home without mechanical intervention. Well, this holds true in the summer when it's cooler inside the home than outside. Our strategy with the fan is to run it at night and in the morning to bring down the temperature in the home. Around mid morning we'll turn the fan off and close the windows and doors to keep the cold in. In the spring this was a good enough tactic to keep the house comfortable all day without having to use our AC. I'm anticipating the same results in the fall as it's worked well for us the last few days.
The difference in energy consumption between my whole house fan and my whole house AC are very significant. As I mentioned, my AC uses between 3,000 and 3,500 watts while it's running and the HV1600 uses only 100 to 150 watts depending on the speed setting of the fan. Payback is completely dependent upon the amount of time you're substituting one for the other. If your home has good shading or temperatures are cooler, your payback with be quicker. Based on the amount of time we run the fan, my anticipated payback is around 2.5 years.
Stay cool!
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