Outside air intake

[atsah]

A mason I know quite well does not suggest piping outside cold air directly to any double walled fireplace 'boxes'.
He claims that it only accelerates serious rust/corrosion to the firebox.
Makes sense to me, drawing humid air sure can't be good for hot steel.

I agree... Part of the OP's issue is probably draft related..

 

[HawkinsHollow]

I am not sure if this has been covered yet, as I have not read all of the posts BUT. I have been wanting to put one in for humidity reasons. I have been told that the reason houses get so dry when the stoves are burning is because the outside air being sucked into the house is MUCH drier due to the fact cold air holds less moisture. Does anyone else subscribe to this theory?

 

[Grumpycat]

I am not sure if this has been covered yet, as I have not read all of the posts BUT. I have been wanting to put one in for humidity reasons. I have been told that the reason houses get so dry when the stoves are burning is because the outside air being sucked into the house is MUCH drier due to the fact cold air holds less moisture. Does anyone else subscribe to this theory?

Not much of a theory as it is hard fact.

The weather service specifies “%RH”, relative humidity, as the percentage of moisture the air is holding at current temperature and pressure. If it reaches 100%RH then wet water starts falling out. Also specifies dew point, which is the temperature this air will reach 100%RH. With %RH, dew point, and current temperature one develops an intuition that one would lack if told how many grams per kilogram or water is in the air.

I agree you do not want the fire to burn your warm moist air. You do not want to suck cold outside air in through nooks and crannies in rooms distant from your fire. This only makes those rooms colder. Is a good idea to put a pan or bucket of water on your wood stove to raise the interior humidity.

As for outside air both the fire and occupants need fresh air for pretty much the same reason. Would be a good idea to have a CO2 (carbon dioxide) and CO (carbon monoxide) monitor to make sure of the quality of air.

 

[oosik]

We started out with a wood stove - ten years. Then we went to a pellet stove - fifteen years. We always had a tea kettle full of water on the stove. Good for a quick cup of tea & try to keep the humidity up in the house.

 

[KennyG]

A mason I know quite well does not suggest piping outside cold air directly to any double walled fireplace 'boxes'.
He claims that it only accelerates serious rust/corrosion to the firebox.
Makes sense to me, drawing humid air sure can't be good for hot steel.

I'm skeptical of this. On a cold day, even 100% humid air will be very low humidity when it warms to room temperature, let alone stove temperature. There is no possibility of condensation and therefore, no potential for moisture caused corrosion. Combustion of wood causes way more water vapor to be produced than could ever be in the air intake.

 

[MotorSeven]

Our house is far from tight (old farm house redone) but I added an outside combustion air intake to our stove anyway simply because the combustion air has to come from somewhere and without outside air, it's pulling in outside air wherever it can and why heat the outside air to have it go up the flue.

Does it make a difference, not sure but it did eliminate the cold drafts to a degree. Minimal fabrication too. I used corrugated foil heat riser (automotive) hose for the inside (wall to stove) intake and made a sheet metal bulkhead fitting for the inner and outer walls with a suitable length of 3" galvanized flue pipe in between. Think the whole thing was under 20 bucks. I did it about 5 years ago so it might be more for materials now. I screened the intake on the outside to keep bugs out in the summer.

Same here. On the wood burning furnace the OAK is recommended, but it took me a while to get around to installing it. Made a big difference on quality of the burn, and which meant a marginal heat output increase. It's a simple system, easy to install.

 

[ruffdog]

Good article on the subject:

A non-commercial service in support of responsible home heating with wood - The Outdoor Air Myth Exposed

 

[atsah]

Good read and what I believe to be true...

 

[arrow]

Good article on the subject:

A non-commercial service in support of responsible home heating with wood - The Outdoor Air Myth Exposed

Generalities hold more truth than particulars in my mind. Lets elucidate: I have a Quadrafire 5700 with a 3 cu ft bx. and secondary tube burn. It is placed in the unfinished cellar. It is heating about 2000 sq ft log home with very poor R numbers both for walls and roof. As it is a "log home", there is little option to add more insulation for either the roof or the walls unless I'm willing to lose the character of what the aesthetics provide and I'm not inclined to do so. Sq footage includes the cellar, main floor and 2nd floor. Foundation sills are caulked and insulated. Foundation is not.
The heat rotation is created by keeping the cellar door open. There is a laundry chute from the second floor whose lid needs to be kept open or I get about half the heat so apparently, that is part of the rotation- convection path.

House is sufficiently heated until we get several days of 25* weather. At that point, oil burner is kicked on to aid with hydronic system heating house sufficiently.

Now I can make all kinds of projections based on theory. One of which that is woorisome to me is : with an o.a.k. will I screw up the natural heat rotation that is happening now? I can feel the rush of cool air coming down to the stove via the stairs at my feet and also notice the rush of warm air at head level on these same stairs. Don't know if the mere heat is doing this or if the stove is creating enough combustion need to aid with this draw?

There are no registers in the house with the exception of one directly above the stove. I am thinking of getting a powered register for this area to see if it will pull more heat from the cellar.

Further reading the article that atsah provided, it states that there is little combustion draw that the stove is creating. What Ido not know and what the article does not state is what a cumulative effect might have in the overall heat retention if the stove does not need "room air" for combustion.
Its all touchy-feely at this point.

My question was put forth in hopes of someone having the same situation and what, if anything, an outside air kit provided.

 

[ruffdog]

Generalities hold more truth than particulars in my mind. Lets elucidate: I have a Quadrafire 5700 with a 3 cu ft bx. and secondary tube burn. It is placed in the unfinished cellar. It is heating about 2000 sq ft log home with very poor R numbers both for walls and roof. As it is a "log home", there is little option to add more insulation for either the roof or the walls unless I'm willing to lose the character of what the aesthetics provide and I'm not inclined to do so. Sq footage includes the cellar, main floor and 2nd floor. Foundation sills are caulked and insulated. Foundation is not.
The heat rotation is created by keeping the cellar door open. There is a laundry chute from the second floor whose lid needs to be kept open or I get about half the heat so apparently, that is part of the rotation- convection path.

House is sufficiently heated until we get several days of 25* weather. At that point, oil burner is kicked on to aid with hydronic system heating house sufficiently.

Now I can make all kinds of projections based on theory. One of which that is woorisome to me is : with an o.a.k. will I screw up the natural heat rotation that is happening now? I can feel the rush of cool air coming down to the stove via the stairs at my feet and also notice the rush of warm air at head level on these same stairs. Don't know if the mere heat is doing this or if the stove is creating enough combustion need to aid with this draw?

There are no registers in the house with the exception of one directly above the stove. I am thinking of getting a powered register for this area to see if it will pull more heat from the cellar.

Further reading the article that atsah provided, it states that there is little combustion draw that the stove is creating. What Ido not know and what the article does not state is what a cumulative effect might have in the overall heat retention if the stove does not need "room air" for combustion.
Its all touchy-feely at this point.

My question was put forth in hopes of someone having the same situation and what, if anything, an outside air kit provided.

Heat rises and cold air sinks. Warm air will be at head level going up the stairs because it rises. At the same time, cold air is taking the place of the warm air and is seeking the lowest level. It is what happens in a structure with multi levels and one heat source. It works great when your burner is in the lowest level because your cold air is coming down to be heated. A cold air inlet only helps when you lack enough air to feed the burning process because the house is tight.

I grew up with the same situation. We had a door leading to the upstairs bedrooms that we would adjust to vary how much warm air goes up. The only way to fix it is a forced air system with cold air returns. Or, just work with it.