Adding a vent to flow heat upstairs

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wahoowad

Minister of Fire
Hearth Supporter
Dec 19, 2005
1,680
Virginia
I was explaining to a coworker about how my woodstove heat tends to stay in my den with the vaulted ceiling. He suggested I cut a vent higher up on the peaked part of the wall to let captured heat flow into the upstairs. Attached is a diagram. I drew a red vent up on the wall where this could be done. A spare bedroom is on the other side of that wall. The vent would be on the lower part of this bedroom wall. I would try to use vents that look like the existing ones used by my heatpump ductwork. He said this would aid in establishing a convection flow where cold air would flow into my very warm den as warmed air flowed through the vent into the upstairs.

I'm not trying to tie this in with my ductwork. This would be a pass-thru. And I do already have a ceiling fan in this room as well as a small box fan forcing cool air into this room (so that it spills out the top of the doorway and the kitchen opening). I could just use more help distributing the heat.

Craziness?
 

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Hot air will never be able to penetrate into that vent. The colder surface air at lower levels, will win every time. Supply without return is useless

Return without supply again useless.
 
I have been toying with cutting a vent into a wall as well, but in my case I would be putting it right next to the ceiling on the wall oposite the stove.

That would let the heat into a corridor that that houses a stairwell that runs parrallel to this wall..

The cold air could return by coming through the doorway at the end of the hallway (about 10 feet away)

The reason that I have been considering this is that I suspect a lot of hot air gets trapped by the lintel / 1.5" of wall over the door, never making it to the second floor.

Is that any better of an idea?
 
wahoowad said:
I was explaining to a coworker about how my woodstove heat tends to stay in my den with the vaulted ceiling. He suggested I cut a vent higher up on the peaked part of the wall to let captured heat flow into the upstairs. Attached is a diagram. I drew a red vent up on the wall where this could be done. A spare bedroom is on the other side of that wall. The vent would be on the lower part of this bedroom wall. I would try to use vents that look like the existing ones used by my heatpump ductwork. He said this would aid in establishing a convection flow where cold air would flow into my very warm den as warmed air flowed through the vent into the upstairs.

I'm not trying to tie this in with my ductwork. This would be a pass-thru. And I do already have a ceiling fan in this room as well as a small box fan forcing cool air into this room (so that it spills out the top of the doorway and the kitchen opening). I could just use more help distributing the heat.

Craziness?

That is how the heat worked in homes over 100 years ago.
My old house had that system when I moved in . A large coal
burner that was converted to oil. It was in the basement and the heat would rise via a 3 ' x 3' grate in the floor. Then it would get upstairs by 10" x 20' adjustable in each of the bedroom upstairs.
It would keep the house warm but I wanted more control so I installed a boiler and radiators.
Give it a shot at worst you will have to repair the drywall.
 
Air flow is not a one way street. If you want air ( warm or cold ) to flow in you have to remove the same amout of air from the space. This is why Air handlers ( furnace, heat pump, etc ) have returns. It sucks the same amount of air out of the space as it blows in. If you dont think this is true tape a piece of plastic over the cold air return on your furnace and see how well it works. ( Dont do this for a long period of time )
 
The vent will work, but only with some assistance from a fan blowing (actually sucking) the heated air into the upstairs. A quiet exhaust fan can be retrofitted and be unobtrusive if done properly. If you don't want to use a fan then you're going to need a much larger vent hole than what you have pictured.
 
If you do decide to do this please make sure you get a fusible link smoke damper inline with the fan and duct.

There is no reason, for the 12 or 14 dollars the dampers cost, that you shouldn't have one.
 
elkimmeg said:
Hot air will never be able to penetrate into that vent. The colder surface air at lower levels, will win every time. Supply without return is useless

Return without supply again useless.

This is the truth. Been in homes with "hot air ducts" above the stove, and they dont work

I posted this last year, and your best bet is to have a circular fashion of hot air climbing away from the stove and cold air falling and running back to the stove. Cut that path off, and you will fail.

Lived on the 3 level of a cape in WV, with the stove in the basement, and my bedroom was on the 3rd level.

If you kept the doors open, there was a strong warm breeze above every doorway, and a cold draft at the bottom. The 3rd level was not really warm, but it wasn't freezin either.

In a game like that, it is all about momentum. Keep the stove going, keep the air flowing.

Your not going to fire up a stove when its 25 outside, and expect the upstairs to be toasting warm in an hour or two.

Wanna prove the point? Put a thermometer at the top and bottom of the doorways. Thats how I learned.
 
Sandor said:
elkimmeg said:
Hot air will never be able to penetrate into that vent. The colder surface air at lower levels, will win every time. Supply without return is useless

Return without supply again useless.

Wanna prove the point? Put a thermometer at the top and bottom of the doorways. Thats how I learned.

Great suggestion Sandor!
 
my grandfather has an old warm morning stove on a hearth in the middle of a HUGE family room.

the single level house is probably 2500 sq ft, the back bedrooms got cold at night.

we installed a return air intake directly over the wood stove.
he moves a baffle to select it, or a different intake winter/summer.

insulated the ductwork.

he looses about 10 degrees degrees of temp from the ceiling over the stove, to the back of the house ( vent temps in the 93 degree range)
after running for an hour, he looses almost NOTHING as the ductwork heats up.

the hvac fan circulates the heat through the house, and has been working fine for over a decade.
 
we installed a return air intake directly over the wood stove.

so much for code requiring 10' separation distance from a combustion appliance

then there is another code that forbids a vent of any type in the same room of a combustion appliance
we all know that would exclude most wood stove installations and is never enforced

Then there is using a system for a used it is not designed and listed for that purpose. Your hot air furnace is a closed combustion chamben the heats an exchanger the heats the air to be transmitted. That's the design of the duct system. It was never designed to remove heat from an open source combustion vestel (wood stove)

What bothers me most is the increased fire and smoke danger, especially when introductd into bedrooms. When sleeping are we most vurerable to dangers?

I can not stress how dangereous this practice is. I rather add another, blanket then be exposed to the potential risk.

I know that's me better safe than sorry. People will go ahead and cut holes in natural containment floors. Others will do it, then advocate this practice without ,
expressing increased dangers. All I can do is point out there are risk involved, ones I'm not willing to compromise.
 
there is probably 4-5' from the top of the stove to the intake on the ceiling.

We didnt feel foolish for making the house warmer and more comfortable, and Ive never felt foolish for sleeping there.

It works, tried, tested, proven, warm, comfortable, and at least as safe as mowing your yard, or using a power tool.

Thanks for your ever vigilant attempt to keep people aware though.




elkimmeg said:
we installed a return air intake directly over the wood stove.

so much for code requiring 10' separation distance from a combustion appliance

then there is another code that forbids a vent of any type in the same room of a combustion appliance
we all know that would exclude most wood stove installations and is never enforced

Then there is using a system for a used it is not designed and listed for that purpose. Your hot air furnace is a closed combustion chamben the heats an exchanger the heats the air to be transmitted. That's the design of the duct system. It was never designed to remove heat from an open source combustion vestel (wood stove)

What bothers me most is the increased fire and smoke danger, especially when introductd into bedrooms. When sleeping are we most vurerable to dangers?

I can not stress how dangereous this practice is. I rather add another, blanket then be exposed to the potential risk.

I know that's me better safe than sorry. Fools will go ahead and cut holes in natural containment floors. Other fools will do it, then advocate this practice without ,
expressing increased dangers. All I can do is point out there are risk involved, ones I'm not willing to compromise.
 
My picture at the start of this thread shows 2 original HVAC vents on this wall. They are connected via ductwork to all the bedrooms of my house. I am not aware of any smoke dampers inside this ductwork. Should I seal off these vents to keep a fire from spreading to all my other rooms?

I agree with Sandor that I will not achieve much airflow without some kind of fan assist, and I don't feel like fooling with that. I thought the rising heat would help flow through that vent. There is a set of stairs leading downstairs right next to that room.
 
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