Outside air intake

[arrow]

Having heard various opinions about getting combustion air for your wood stove from an outside source rather than the room its in. Wanting to listen to some real world experiences, just wondering what anyone truly noticed with any warmth advantage or not who decided to go the o.a.i. route.
I do suppose like everything else, the devil is in the details but my wood stove resides in the unfinished cellar heating it, the main floor and the second floor. It struggles when temps get to 25* and below to keep the entire house warm as it does with temps above that. Cellar sills are insulated and caulked.

 

[RNeumann]

This has little to do with the heat output. This is done because houses are built tight enough that the combustion air needs to come from somewhere. I couldn’t run a bathroom fan and certainly not the range hood if I wasn’t getting combustion air for my firebox. If you have a tight house you’d benefit from dedicated combustion air.

 

[5030]

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.

 

[5030]

Why I was never a fan of a fireplace. Sure the fire feels good and warms you as you face it but, most of the heat is up the chimney and all the makeup air is pulled in from the outside (cold) air.

Why, back in the day rooms had 2 fireplaces. That way you could be warmed on 2 sides instead of one but the rooms were cold because all the heat was going out the stack.

 

[arrow]

This has little to do with the heat output. This is done because houses are built tight enough that the combustion air needs to come from somewhere. I couldn’t run a bathroom fan and certainly not the range hood if I wasn’t getting combustion air for my firebox. If you have a tight house you’d benefit from dedicated combustion air.

Everything you state is correct but I'm not questioning the heat output. I'm asking if there is an advantage for room ambient temp staying more constant or even increasing for not having to be sucked backed into the stove if indeed the stove is being supplied combustion air from the room as opposed to an outside source.

 

[5030]

We have a condensing central furnace in addition to the woodstove and it's combustion chamber is sealed and it's combustion air is all outside (ambient temp) air as well.

 

[5030]

Absolutely. If it's say -5 outside, that air being drawn in and going up the flue is heated to room temp prior to being used for combustion. One thing I've found with outside air is, when it's bitter cold out, the cold intake air seems to created a better burn. I actually get frost on the intake pipe sometimes.

Heating that air coming in requires more fuel in the stove to maintain a comfortable temp in the room. I don't know how much less fuel I use but I do know I'm not deeding the stove as much now as I was before.

Considering the cost. it was worth it but then my stove was built with an outside air intake in the unit itself.

Here we are talking about cold already and I have to cut hay next week...lol

 

[DIYOrangeDave]

I had a Heat Recovery Ventilator installed after I install my second wood stove. I also had the technician set it up bringing slightly more air in than going out providing a positive pressure of air in the house. This eliminated the down drafts when not in use and made for easy lighting when cold.
As far as how it feels, the 2 wood stoves heat 2200 sq ft nicely as long as you are feeding them every 2-3 hours. Over night my heat pumps come on so it doesn’t cool off too much. Even down to -15C they are enough to have the bedrooms cool and the living area toasty.
And don’t forget that wood warms you every time you handle it.

 

[arrow]

Ok, thanks for the input guys. I'm going to install one and see what happens this burn season. The stove I have does have provision for direct hook up. I'll report back later with the results.

 

[dfkrug]

The stove I have does have provision for direct hook up.

On my Regency woodstove that I installed 20y ago in my new house, there was a "mobile home kit" that was used to bring in outside air. It went thru the bottom of the stove, inside the pedestal, so the ducting goes thru the floor and up the outside wall of the house to a screened vent about a foot off the ground.

It works fine, but it is hard to compare it to a setup that burned inside air. My house is extra-tight ICF construction, so O.A. is especially important. My 34K BTU stove has no problem keeping my 2100sf house warm, but my winters are mild.

I do have to be careful when running any exhaust fan, and opening the stove to add wood. I rarely run my propane central heating system.