whole house fan with a wood burning appliance

Forrest3290

New Member
Apr 20, 2019
24
Salem, Oregon
I know this thread is super old, but has anyone installed a whole house fan specifically for SUMMER cooling (flip it on in the evening when the temps are down etc and again early AM to get the home down in temp) and the worry is that it could pull air down the chimney etc. and make the whole place smell like soot.
 

begreen

Mooderator
Staff member
Nov 18, 2005
78,033
South Puget Sound, WA
Moved to its own thread.

It may not be an issue in summer because usually, one has the windows open in order to draw in cooler air from outside. However if insufficient windows were open and the fireplace damper was open, then yes this could be an issue.

Another issue can happen in the winter. Typically a whole house fan pulls air from the house thru a large grille in the ceiling. That grille needs to be sealed off during the heating season to prevent the stack effect from creating negative pressure in the floors below.
 

Forrest3290

New Member
Apr 20, 2019
24
Salem, Oregon
Awesome, thank you, that is what I was thinking. The versions we are looking at have insulated doors that open and close before the fan operates. I was told the same thing on the windows, that air will come from wherever it can come from easily. I was hoping to be able to automate this, but I think a good safety check would be to make the fan manual to act as a reminder to open a window or door.

Thanks for the reply! Long time lurker and wanted to jump in now that I think I have some info to offer (mostly about cutting and drying white oak and other woods in the PNW.)
 

begreen

Mooderator
Staff member
Nov 18, 2005
78,033
South Puget Sound, WA
No oak up here. You are very lucky if it is in your neighborhood. White oak is dense and takes a long time to season, at least 2 years.
 

Forrest3290

New Member
Apr 20, 2019
24
Salem, Oregon
Yeah, we have a TON of it. It gets cleared out for the vineyards etc. Oregon white oak, awesome stuff, tough to split but wow does it burn well. We have several large burn piles we need to cut up and get stacked (from land clearing) that have been sitting there for a year and a half now
 

FPX Dude

Feeling the Heat
Oct 4, 2007
297
Sacramento, CA
I use it all the time, as long as you have enough windows open you won't have a problem, oh and I stuff a towel in the damper flue about now just to make sure. But heck, I even use the fan in the middle of winter when I'm burning and I get it a little too warm, I open the slider and pull in some nice clean cold air for a few minutes or so, only on the low speed though, the high speed will reverse the draft (if you wanna know how I know, ha!) :)
 
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JBinKC

Feeling the Heat
Jan 14, 2006
304
Lake of the Ozarks
I use this sort of system to supplement cooling and I have no problems with regard to the chimney imparting odors to the house while the system is in operation. It is neighbors burning habits, wildfires and /or relative low temperatures that prevent usage of the fan.
 
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electrathon

Minister of Fire
Sep 17, 2015
523
Gresham, OR
I have a whole house fan that turns off and on my by a thermostat. If I am not home and the house is closed up when the fan turns on there is a strong smoke smell in the house. The chimney is the easiest place at that time for the air to enter the house. As long as a window or two is open it is not an issue.
 
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FPX Dude

Feeling the Heat
Oct 4, 2007
297
Sacramento, CA
I have a whole house fan that turns off and on my by a thermostat. If I am not home and the house is closed up when the fan turns on there is a strong smoke smell in the house. The chimney is the easiest place at that time for the air to enter the house. As long as a window or two is open it is not an issue.
Yikes, I wouldn't want a WHF on a thermostat, but definitely need to make sure enough windows/doors open to account for the volume of air these things can pull w/o getting the chimney involved.
 
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electrathon

Minister of Fire
Sep 17, 2015
523
Gresham, OR
Yikes, I wouldn't want a WHF on a thermostat, but definitely need to make sure enough windows/doors open to account for the volume of air these things can pull w/o getting the chimney involved.
It also has an on/off switch on it. The thermostat allows it to run into the evening and turn off when the house has cooled.
 

PaulOinMA

Feeling the Heat
Oct 20, 2018
349
MA
We also have a whole-house fan. Odor from the chimney has never been an issue. Have to have a LOT of square footage of windows and sliders open to use the whole-house fan per manufacturer's instructions, so pulling air from the chimney is not a concern.

I also insulate the top of the fan in cool weather, as mentioned above. I then put a piece of tape over the switch on the wall by the fan to remind me to take the insulation off in the spring before using the fan.
 
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peakbagger

Minister of Fire
Jul 11, 2008
4,605
Northern NH
I have had a WHF for 25 years and only use it in the summer. Is a very large unit compared to my square footage but the price was right. Its sealed up with 2" think ISO board foam cover in the winter. If I run it in the summer with all the windows closed it definitely backdrafts the oil burner flue via the barometric damper and also backdrafts the wood flue. I know better and just open the windows first. Mine is on a digital adjustable timer. Its a two speed unit but does not like to start at low speed so I start it on high and then switch it to low when its running. Its gets used less since I put in the minisplits as typical hot weather in New England lines up with high humidity. I can run a higher temperature setting on my minisplit in the house and be comfortable as long as the humidity is low.
 
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begreen

Mooderator
Staff member
Nov 18, 2005
78,033
South Puget Sound, WA
We also have a whole-house fan. Odor from the chimney has never been an issue. Have to have a LOT of square footage of windows and sliders open to use the whole-house fan per manufacturer's instructions, so pulling air from the chimney is not a concern.

I also insulate the top of the fan in cool weather, as mentioned above. I then put a piece of tape over the switch on the wall by the fan to remind me to take the insulation off in the spring before using the fan.
If there is a ceiling grille that vents to the attic space then it too should be insulated and sealed well for the winter.
 
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Forrest3290

New Member
Apr 20, 2019
24
Salem, Oregon
AWESOME! Thanks, everyone for the input and advice! Our place gets pretty breezy in the evenings and it cools off fast but the home has been baking in the sun all day, would be great to kick all that heat out. I think we will be putting in two stoves so that should make it a bit easier to control the draft. I for sure will have a big RED button saying OPEN A FLIPPING WINDOW OR TWO BEFORE PUSHING! Haha
 

PaulOinMA

Feeling the Heat
Oct 20, 2018
349
MA
If there is a ceiling grille that vents to the attic space then it too should be insulated and sealed well for the winter.
My whole-house fan is the in-ceiling type where it vents to the attic, so that's what I cover. Or, am I missing something else? I've lived here 16 years. I'll be really ticked if you make me go find something that I should have been covering all these years. :)
 

PaulOinMA

Feeling the Heat
Oct 20, 2018
349
MA
… OPEN A FLIPPING WINDOW OR TWO …
Check the square feet you're supposed to have open for your fan. I'm supposed to have more than one or two windows open based on the cubic feet the fan pulls.
 
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