Hello all. I would like to install a whole house fan in order to save
on air conditioning costs. I live in Denver, where there aren't that
many really hot days during the average year. However, my house gets
really hot during the day; especially the upstairs. It's usually
reasonably cool at night when I am home but it takes the air
conditioner a long time to catch up. After seeing how well my friend's
whole-house fan works, it seems a no-brainer to me to put one in.
However, I wanted to possibly do something a little different.
Last September my high efficiency furnace died. The fan still worked
fine though. I ended up keeping the fan, thinking I could use it for a
whole-house fan. I like the idea of using this type of fan since they
move a lot of air but are much quieter than standard blade fans.
I've already measured and the fan will fit through my attic access
opening. The main difficulty I see is that since this type of fan
takes air in on two sides and blows it out the top, I will need to
construct a box around it to seal the intake. This doesn't seem too
difficult. I was thinking of just using plywood and 2/4's rather than
The second problem is shutters or louvers. I went to Home Depot and
found only complete fan kits including the louvers. The whole kit was
only $209. I would like to find reasonably priced louvers, and if
possible, I would like to get power louvers.
Does anyone know a good place to order a reasonably priced louver that
does not require cutting joists?
Lastly, I still need to measure my existing attic vents to see if I
have enough. If not, I will need to add more but I don't know what
kind I need. That is, could I just increase the side of the side vents
of would I need more rooftop vents? I feel comfortable doing the side
work but I don't feel comfortable cutting holes in my roof.
Does this whole thing seem like a good idea? Any thoughts?
Thanks in advance.
Well, I don't think I would do it. The furnance fan is designed to move
air against a given static air pressure, a whole house fan is designed to
for different conditions. I suggest you will have better results using a
real whole house fan. Many are reasonable quiet. Don't go for the cheapest
small diameter one you can find.
BTW in most cases I would have said that your idea of using a fan part
of the day and A/C part of the day on hot days was also not a good idea, but
in Denver it may well be a good idea.
Best of Luck
I have a couple of $73 4TM66 16" window box fans from Grainger. They do
a good job, with a free air delivery of 5850 cfm at 90 watts (65 cfm/W :-)
vs Certainteed's $250 3C374 30" whole house fan with a free air delivery
of 5700 cfm at 400 watts (14 cfm/W) or the $12 Holmes 20" window box fan
that moves 800 cfm with 100 watts.
Seems OK to me, as long as the AC doesn't cool the house to less than
the dew point of outdoor air, which seems very unlikely in Denver.
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