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phutch85
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# Posted: 18 Oct 2021 04:20pm
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Hi all,
Searched for this topic but couldn't find anything. Hoping someone else here has run into this issue and has a creative idea.
Just finished building a 240 sq. ft. cabin with loft in the PNW. We've got two sources of heat, a simple Cadet Compak wall heater and a small woodstove made by North Woods Fabrication in Minnesota.
The stove is wonderful, but we're having an issue with fresh air intake. North Woods does not include an air intake option for their stoves and we built our cabin quite tight. To get a fire going and to maintain it, we have to keep one of the windows in the cabin (doesn't matter which one) at least cracked. As soon as we shut the window, we got a powerful backdraft and smoke pours into the cabin.
It'd be one thing if we were the only ones using the place but we plan on renting it out to guests when we can't get up there. As such, we'd like a more foolproof way to ensure fresh air for the woodstove when guests make a fire.
Since a direct connection to the woodstove would require custom fabrication I'm looking at indirect intake solutions. My thought is to add a simple floor drain beneath the woodstove to a piece of abs that is open to the outside. I'd put a drain cover on the outside as well to ensure critters couldn't get in.
Obviously, this would allow cold air to seep into the cabin at all times, but it seems like that's a downside to any indirect air intake that doesn't require people to know or remember to manually open some kind of damper. Thoughts?
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Fanman
Member
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# Posted: 18 Oct 2021 05:34pm
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Perhaps a gravity (backdraft) damper on the intake duct?
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ICC
Member
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# Posted: 18 Oct 2021 07:32pm - Edited by: ICC
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My thoughts are that if you are renting this place out you need something that is idiot proof. I've seen people build wood fires, or try to, in a gas-only fireplace.
I think making idiot proof requires a custom fabricated sheet meal box around the inlet of the stove. I could not see that stove model on that makers website.
My woodstoves were made by a company that use a rear inlet that makes that very easy. They supply fresh air inlet kits.
If you can draw air through a wall there are "flap vents" that are the reverse of the dryer exhaust vents we all have seen. The flap opens inward when air is drawn in by the stove.
A vent hole through the floor should not be a source of drafts into the home if there are baffles under the floor.
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Brettny
Member
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# Posted: 18 Oct 2021 07:37pm
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What does the intake of the stove look like? I made a custom one for my stove.
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gcrank1
Member
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# Posted: 18 Oct 2021 08:55pm
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Renting it out will be a whole lot more liability and requirements. Have you looked into that?
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DaveBell
Moderator
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# Posted: 18 Oct 2021 10:05pm
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https://heatredefined.com/
Outside Air Kit for Wood Stoves
https://heatredefined.com/collections/15-ssw02-50-shssw02-and-50-trssw02/products/ac- oak3
Give them a call. They are in Virginia. I would think all you need to do is buy a 3" metal hole saw and then drill holes for mounting screws.
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KelVarnsen
Member
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# Posted: 19 Oct 2021 08:12am
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Quoting: phutch85 we're having an issue with fresh air intake. North Woods does not include an air intake option for their stoves and we built our cabin quite tight. To get a fire going and to maintain it, we have to keep one of the windows in the cabin
This is on my to do list too. I recently insulated and sealed my cabin and now it is difficult to start and keep a fire going in my woodstove.
This guy has some good videos and does some testing with and without the intake.
Apparently, there is some controversy as to whether or not connecting fresh air poses a danger. Article 1, Article 2.
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ICC
Member
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# Posted: 19 Oct 2021 09:41am - Edited by: ICC
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Quoting: KelVarnsen Apparently, there is some controversy as to whether or not connecting fresh air poses a danger. Article 1, Article 2.
The woodheat article was originally published in 1996. It keeps getting dragged up every once in a while when this subject comes up.
Using a fresh air intake of some kind makes a lot of sense to me. A wood-burning stove with an outside fresh air supply becomes very similar in operation to modern fireplace inserts that burn NG or propane. Those are basically the same design as a NG or propane direct vent wall heater. Those all use combustion air from the outside.
A gas-burning water heater inside a habitable space must be equipped with a fresh air inlet vent. The same rule applies to a gas-burning furnace if the furnace is within the habitable space. Water heaters and furnaces are often in a closet in homes built on concrete slabs. A vent pipe is used to draw air from the ventilated attic space.
My new furnace is so efficient it uses a piece of PVC pipe for exhaust as well as inlet air.
If as woodheat suggests, a backdraft situation was so bad as to shoot fire into the inlet piping and cause a fire I would think that there would be flames shooting out into the room if there was no inlet venting.
One of the "problem" situations that woodheat presents has the wood burning chimney too close to he roof peak and not high enough.
The OP has proved that their wood stove needs inlet air to function properly. Many others had proved this same thing to themselves. You can either open a window and probably cause cold drafts that make your new cozy home feel like the drafty old homes I grew up in.
Sure there are wrong ways to do fresh air to a stove, but that can be said about everything.
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gcrank1
Member
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# Posted: 19 Oct 2021 10:42am
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You absolutely need to start with having all the chimney requirements correct before anything else; ie, height above the peak/obstructions, the size pipe for the woodstove, insulated pipe outside, etc.
My old air-tight pamphlet had detailed instructions on making a cold-air inlet beneath the stove to pipe into a knock-out in the stove bottom. Im sure you will find similar for any new air-tight.
I had considered using the concept with my antique upright by putting a pipe right under the draft control so the cold-air intake had the shortest run. Insect/rodent screen outside and a pop-off cap inside made sense to me. I never did it, cracking the window was considered 'good sense' back then and worked for us.
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phutch85
Member
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# Posted: 19 Oct 2021 12:18pm
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Thanks for the thoughts all, including the links to the aftermarket air intakes. I'm hesitant to start cutting holes in the stove just yet.
As far as I know the stove and chimney pipe are all installed correctly and to code. This is the fourth woodstove I've installed on a tiny cabin so I'm pretty clear on the necessary clearances. No bends to deal with here, just a straight shot up through the roof.
ICC, you're thinking is similar to where mine has been going. As an alternative to the floor drain vent idea, I came across this style vent that's designed to prevent backdrafts: https://www.lowes.com/pd/IMPERIAL-4-in-Plastic-Dryer-Vent-Draft-Blocker/3126471
That draft blocker combined with an outside vent cover that's caged against critters but open against air would be an interesting way to go. I still think I'll start with the floor drain vent because I can hide it beneath the stove in the back of a cubby where we store extra wood. If that doesn't work, maybe this backdraft vent will do the trick.
If there were no guests using the place, or just friends and family, I'd feel comfortable just telling people to crack a window. But, as I know from running rentals before, the typical guest simply will not read instructions!
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Tim_Ohio
Member
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# Posted: 19 Oct 2021 12:48pm
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" I still think I'll start with the floor drain vent because I can hide it beneath the stove in the"
If you can put the vent under the stove, then the air might be warmed from the stove and the room will not have a cold area. I think this is a great idea. Maybe not what you were thinking.
Tim_Ohio
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Brettny
Member
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# Posted: 20 Oct 2021 09:46am
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How does the stove get air? If its through the front door of the stove you have no choice but to use a vent open to the room. If it dosnt intake through the door then you can hook directly to its intake and wont need to vent into the room.
I built an outside air kit for the stove in my house and saw a great increase in heat further away from the stove as well as a decrease in wood use. I also had very little money into it and didnt need to drill any holes in the stove. Not that drilling the stove would have kept me from doing it.
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