mjncad
Super Member
Let me know if you feel the same way if your A-$-$ lands on a hot surface because you were being stupid. I just pointed out a scenario for the OP to think about.
Wood Stove and HVAC Return Duct Proximity
- Thread starter dieselscout80
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Let me know if you feel the same way if your A-$-$ lands on a hot surface because you were being stupid. I just pointed out a scenario for the OP to think about.
OP
dieselscout80
Veteran Member
I may have to move the return duct to get the 10'.
My upstairs return filter is 20"x30" and the HVAC unit is a 5 ton heat pump and the total home is 2700 sqft (1920 sqft upstair).
The current basement return duct is a 10"x20" filter opening attached to the main return line.
I can run it between the floor joist, but can I fit a big enough duct between 2"x10" floor joist on 16" centers (basically a 9.25"x14.5").
What size return ducting and vent is needed for 780 sqft?
If one run in the space between the joists is not enough would it work to do two runs side by side to a common grate/filter?
My upstairs return filter is 20"x30" and the HVAC unit is a 5 ton heat pump and the total home is 2700 sqft (1920 sqft upstair).
The current basement return duct is a 10"x20" filter opening attached to the main return line.
I can run it between the floor joist, but can I fit a big enough duct between 2"x10" floor joist on 16" centers (basically a 9.25"x14.5").
What size return ducting and vent is needed for 780 sqft?
If one run in the space between the joists is not enough would it work to do two runs side by side to a common grate/filter?
Last edited:
clemsonfor
Super Member
It will work , and yes if needed just use the space between two joists.
I turn my 2 heat pumps on to circulate the air. Neither is in the room with the stove but one is one room away and a fan is in the hall its in and i blow cool into the hot room and hot flows along the ceiling. Both help distribute the hot air in the home
I turn my 2 heat pumps on to circulate the air. Neither is in the room with the stove but one is one room away and a fan is in the hall its in and i blow cool into the hot room and hot flows along the ceiling. Both help distribute the hot air in the home
KennyG
Elite Member
I have a return air duct in the basement ceiling (finished) above my wood stove. I added a couple of grills with dampers more or less above the stove and it works great. Open when the wood stove is hot, closed when it's not. I put in two moderate sized grills because a large one with a damper was way overpriced.
The only problem I have had with my system is that I put in an airtight stove. I have combustion air ducted from the outside at grade down into the stove. When the stove is cold, the ash drawer is not quite airtight and I get some ash smell forced out by the cold air pressure from outside. I'm adding stove gaskets on the ash drawer this year and we'll see how it works.
The only problem I have had with my system is that I put in an airtight stove. I have combustion air ducted from the outside at grade down into the stove. When the stove is cold, the ash drawer is not quite airtight and I get some ash smell forced out by the cold air pressure from outside. I'm adding stove gaskets on the ash drawer this year and we'll see how it works.
Could you put a damper on the cold air duct? If you could put that as close to the outside wall as possible, it would probably help efficiency a little to keep that duct at room temp when you're not using it.
KennyG
Elite Member
That's a good idea. However, I already added a dryer vent shut off valve to the air intake last year as a first step and that helped some. When the stove is cold, I still got some backflow, probably from back down the chimney. Wood stoves in basements are kind of a challenge because of the cold air pressure differences.
OP
dieselscout80
Veteran Member
How would you control the damper?
andrehoude
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dieselscout80 said:
I am ventilation expert I do not recommend doing this because temperature from wood stove is to hot and the next question is Is your return air space made of combustible material or completely lined with sheet metal also the forced air systeme will bring the room under negative pressure And if it's lined with sheet metal it can make noise because it expending do to the heat
I just would not do it.
Sorry
OP
dieselscout80
Veteran Member
The return duct is all sheet metal.
CAn you shed any light on my eailer post about moving the reduct and return duct sizing?
http://www.tractorbynet.com/forums/2612049-post12.html
s219
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Check fire codes. There are two potential issues at play.
First, the duct could be considered a flame and/or fuel path to other parts of the house should something go wrong at the stove (and whether or not it's metal is irrelevant here). You sure don't want to have a direct path to other parts of the house for flames or oxygen to flow through if there's a problem down by the stove. It could make a small problem become a big problem real quick.
Second, the duct intake and air filter may not be rated to be above a hot stove. Stoves all have certain horizontal clearance requirements that most people are familiar with (proximity to walls or furniture, for instance). Vertical clearance above the stove is often overlooked, but it's just as critical since the heat rises and naturally gets focused above the stove. I wouldn't want a soft filter right above the stove myself.
I do think it's important to circulate heat from a stove to the rest of the house -- otherwise the room with the stove can be unbearably hot while the rest of the house is cold. Just do it in a way that doesn't increase fire risk. Good luck!
First, the duct could be considered a flame and/or fuel path to other parts of the house should something go wrong at the stove (and whether or not it's metal is irrelevant here). You sure don't want to have a direct path to other parts of the house for flames or oxygen to flow through if there's a problem down by the stove. It could make a small problem become a big problem real quick.
Second, the duct intake and air filter may not be rated to be above a hot stove. Stoves all have certain horizontal clearance requirements that most people are familiar with (proximity to walls or furniture, for instance). Vertical clearance above the stove is often overlooked, but it's just as critical since the heat rises and naturally gets focused above the stove. I wouldn't want a soft filter right above the stove myself.
I do think it's important to circulate heat from a stove to the rest of the house -- otherwise the room with the stove can be unbearably hot while the rest of the house is cold. Just do it in a way that doesn't increase fire risk. Good luck!
