7.29.2013

Whole House Fans Rule

   This has to be one of the gnarliest projects that I have taken on. Anytime fiberglass insulation is involved, you know it is going to be a hot and sweaty, itchy mess. I acknowledge that this is not one of my most creative solutions, but it took years of contemplation to finally pull-off this ballsy maneuver.
   We have a cathedral ceiling in our main living area and it is a large, closed volume that traps heat. We already have a large ceiling fan, but this cannot evacuate the air mass. Before the recent climate change, air conditioning was not practical in Northwest Montana. Not only that, it is just a band aid. It made more sense to eliminate the source of heat retention.
   After several summers of swapping window fans daily, I finally decided to test the hypothesis. I purchased a 3000 cfm fan, which would exchange my entire house's volume every two minutes, whoa, that's right!
   I opted to vent into an adjacent attic space, which in turn makes the house fan double as a gable fan. It pressurizes the attic forcing the hot air out of the gable and soffit vents, while simultaneously bleeding off the heat from our living room. I chose to add additional soffit venting to make sure the fan could easily exhaust all the air.
Badass Whole House Fan
   The whole house fan is worthwhile only if your nighttime lows are significantly lower than daytime highs. I would say at least down to the 50's at night. The system is less effective when you hit the mid-90's and above. At that point there is little the fan can do because your overnight lows are probably in the 70's or higher.
   After fighting with window fans for seven years, I am very happy with just opening the window and turning the timer on. This unit has proven to be very capable and will start the day with the house in the mid-60's. It typically remains comfortable through early evening. On the hotter days, it immediately takes the edge off, pulling fresh air through the house.
   We also added solar shades and extensive foam and caulking when we painted the house. Like I said before, I am the type of guy who would rather address the source of the problem, than arbitrarily increase my utility bill trying to disguise a bigger issue.

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