I have a two-story house that is currently being blasted by the heat
dome in the NE. What I have been doing the past few days is switching
the fan on my thermostat from AUTO to ON in the evening so the
upstairs won't be so hot then turning it back to AUTO before I go to
bed. I only have one thermostat downstairs so it is always cooler
downstairs. The attic fan that blows out the gable vent is running
I have already blocked all the return vents downstairs and closed all
of the downstairs registers and it has dramatically improved the temp
upstairs but it still needs work. I would like to avoid redoing the
ductwork and making the 2nd floor a separate zone.
I was hoping I could find a thermostat that would kick on the fan say
20 minutes out of every hour regardless of the call for the
The Honeywell VisionPro thermostats do that. At least the newer
not sure about older ones. The fan has 3 settings, on, auto, and
circulate. The first two are the modes all thermostats have. The
circulate mode turns the blower on about 30% of the time, randomly,
during periods when the heat or cooling is not being called for.
You can find them on Ebay for a reasonable price.
On the other hand, from some experimenting with it, I can't say
that having the blower on 30% or even constantly makes a noticeable,
worhtwhile difference at my house. I'd also caution about closing
off too many ducts in your house. I close off two ducts downstairs
that are on the duct that also feeds upstairs. I also added an
inline blower to that duct and those efforts produced significant
improvement. Closing off all the ducts downstairs sounds
extreme and you may not be getting sufficient air flow through
It's sad because these problems could be avoided entirely if
anyone had reasonable skills and gave a damn during
construction. Afterwards, it can be difficult to impossible.
If you have means to add more return duct capacity upstairs
that would probably be a big improvement.
Limp, forgot to mention. Since you mentioned a timer in
your post, the VisionPro circulate feature that I described
can also be programmed into any of the 4 periods for each
day of the week. So, if you want the fan randomly circulating
the air 30% of the time when the AC isn't cooling, you can
have that for just during the day period. The other 3
periods could then be automatic fan, meaning it only
runs when the AC is cooling. Or any of the periods could
be fan on as well.
Thanks. Sounds like VisionPro is the thermostat for me. Now all I
have to do is figure out which one I need to buy. Odd that they don't
mention the fan feature but it is in the manual. I can't be the only
person who lives in a slapped together tract house with an unbalanced
forced air system.
The only difference among the current ones that I'm aware of is
they support 1 stage, 2 stage, or 3 stage sytems. You just need one
that supports what you have as minimum, ie you can use a 2 stage on a
1 stage system.
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