Outside Air Kit (OAK) Install - how to make it look nice on interior wall?

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Slow1

Slow1

Minister of Fire
Nov 26, 2008
2,677
Eastern MA
Ok, I'm looking at hooking up an OAK to my new stove (Fireview). What I'm considering is to run the pipe straight out the back wall behind the stove with rigid pipe (ala dryer pipe). Outside I plan to put some sort of screen and then a cover tbd to keep water from falling in (I have vinyl siding).

So - I'm looking for suggestions and advice here.

1) Is this a reasonable approach?

2) What problems might I encounter with this setup?

3) How can I finish the inside wall to look decent around the hole where the pipe goes through? I plan to paint the rigid pipe with the same color paint as the stove pipes are so that it will blend in, but once it hits the wall there must be a good way to cover up the edges of this hole. The stove is a good ways away from the wall so it won't hide it very well.

Thanks in advance!
 
Not much you can do to hide the ugliness, except to paint and put some kind of trim around it at the wall. Maybe try it without the OAK first and see how it works out?
 
Use a large mesh screen, it will create less restriction. Try to keep the cap off of the leeward side of the house, the negative pressure pocket on the leeward side can create a vacume and make the stove hard to start, and possible reverse the draft if you have a cold smokey fire on a super windy day. If this is the windward side of the building, this is not really an issue. Personally, if you dont need the OAK then i would not install it. The installations of these usually cause more headaches then they intend to fix.
 
I installed mine getting air from the vented crawlspace so no wind issues. Do you have that option? See my sig links for photos. Making the run shorter is better and if I painted mine black then nobody would even notice it.

I don't buy the story from the woodheat site. It makes much more sense to me that the OAK be used if possible. Your cat stove will have lower air requirements than a non-cat.
 
Thanks for feedback folks - I'm finding myself in doubt now... big surprise. I was going along the idea of "it can't hurt and it might be a good idea, might as well just do it and have all this stuff done and over with at once" but now I'm reconsidering. Ug. No particular reason to believe I HAVE to have one here - guess if you believe the woodheat site then there never is a 'have to' reason unless the local laws dictate it. The logic in that article is hard to argue with - but then again I've not researched this all that much.

I have seen posts here from very satisfied OAK folks. I don't know as I've seen anyone with one complain... perhaps I need to figure out a query to flush out those posts.

Highbeam - I don't have a crawl space. Under the stove is my basement which is about 1/2 finished so I think I'll have to go out the wall which means that at some time it will be the downwind side of the house.

So... anyone have first hand bad experience with an OAK to share?
 
Since the OAK can be installed after the installation of the stove, why don't you just try without? It will be less expensive, one less hole in your building envelope, and one less thing to try to make pretty. If the stove does not draft well, or if you think your missing out on some efficiency after the fact, then poke the hole and install the kit. You will find many many opinions on this, just a quick search on this site will reveal heated arguments both ways. I think there is enough data verifying both points of this argument to keep you confused. Every single installation is different, and its very hard to gauge someones success and apply that to your installation. If you can add it later, then why jump off and start with it? The stove will most likely meet your expectation installed the way the majority of stoves are installed. Without a OAK. One reason these kits exist is mobile homes. By law the stove has to be bolted down and a OAK installed. Most manufactures do not want to loose market share to mobile homes, therefor they make kits. Kits are also used in low/negative pressure situations, which are common in super super tight homes with large exhaust fans (kitchen). If this is you, then consider the OAK. If your house is tight without allot of exhaust. Try without.
 
Sounds like the reasonable approach MSG -

One thing that WAS feeding my desire to do it is that if I am gong to do it I have to swap out heatshields. Not a big deal really, only a $60 part so it's peanuts in the big picture but still I hate to waste anything :) Then again - same waste argument goes with spending $50 on the OAK and additional on pipe and the time/hassle of installing it eh?

I do have a fairly tight house - I don't know what exactly qualifies as "super super tight" - I had some attic insulation/sealing work done a few weeks ago. Prior to doing the blower door test the two techs both made their guesses on how where my house would rate on the test... they were both on the order of 30% over and rather surprised... then after the attic work was completed it was down another 10% (much less than their normal % but they said there wasn't much to work with to begin with). I don't have a massive exhaust system anywhere so that shouldn't be competing.

I think I'm going to just go with what I have and see what happens. Worst case I'll live with a window in basement open a bit next winter and/or put the OAK in sometime after the burning season is in full swing.
 
I classify super tight as modern high end construction less then 10 years old. Tyvec, blown celluse, 2x6 or staggered 2x4 construction etc. The biggest problem is really not how tight the home is, air seems to find a way in there one way or another, its the exaust of the house. Some of these modern homes try to replicate commercial kitchens with huge exhaust fans, thats where most of the issues come up. Is this installation in a full basement?
 
The stove is on the first floor, above the basement (then there is one more floor above the floor with the stove). Home was built in 2000, but is 2x4 with standard batting for insulation in the walls. No 'ultra modern - Iron Chef wanna-be kitchen' here - just a normal working kitchen. We do have an exhaust fan integrated in the microwave above the stove but it doesn't even work well enough to justify the noise it makes so it only gets turned on occasionally when the wrong button gets pushed.

It seems as though my desire to avoid potential problems later might just have been risking causing a new one eh? I was under the impression previously that there was no harm in an OAK so the only risk was that I would be wasting the cost of the kit and the time/trouble installing it. Seems there is (like so many things around here) more to the story...
 
I think that you will be happy either way, with it installed or not. So just start with not and see how it goes! i bet you will not be cracking any windows this winter. Please report what you find once it gets cold. Its always good to have record of success stories on both sides of the argument.
 
Can you just install the OAK heat shield and not plumb the oak? Gives you the option to install it later if you want and not waste 60$. Other than that your only risk is not knowing what you're missing out on.

Humidity level is a big benefit along with less drafts. Honestly, I like a dry house and wouldn't be too worried about not using an OAK if the install was particularly difficult or ugly.

For a decent argument about the oak visit tom oyen's site, the chimneysweeponline.com site, and read his pro/against arguments. The woodheat angle is not very good.
 
I'm considering an OAK too, to go with my Hearthstone Homestead stove. This is being re-installed in a set of rooms that have been gutted and completely rebuilt.... anyway. My principle consideration is that with the OAK the stove will not be pulling combustion air from the house. Translated, the stove won't be pulling replacement air into the house- cold air, drafts running towards the stove, generally cooling off the area we're trying to heat in the effort to heat it.

I see the OAK as a method to avoid that.

N
 
this is true, but most people equate the lost air to something like a open fireplace with a 13x13 square flue. The stove flue is relatively small compared to that. Our customers do not complain about feeling any drafts around any doors or widows. The cubic feet of air is minimal going up the wood stove chimney. What we do deal with with outside air kits is obstructions like leaves and crap blocking it, making the stove not draft properly. Also, if there is a long run on the OAK it creates more restriction making the stove perform less then its maximum potential. From a scientific standpoint, doesn't take more energy to bring freezing cold air up to combustion temps then room air? effectively making the stove work harder to achieve maximum efficiency? What about the condensation and freezing cold air around the uninsulated duct work hooking up the OAK?
 
Highbeam said:
Can you just install the OAK heat shield and not plumb the oak? Gives you the option to install it later if you want and not waste 60$. Other than that your only risk is not knowing what you're missing out on.
Click to expand...

Turns out the answer is no - the OAK heatshield is not certified for use without the kit - apparently there is a good sized hole in it that will fail to shield a bit of the wall behind the stove, thus rather defeating the purpose of the shield if the kit isn't installed. So... it is one shield or the other.
 
Rats, and with that rear exit stove setting so far from the wall the area will look like an engine room. I think that the fireview would look way better without the OAK in a freestanding setup.

If room air is at 70 and outside air is at 20 then that's only a 50 degree difference to a 1000+ degree fire. No problem and maybe better since the colder air is more oxygen rich. Constantly heating the infiltrating 20 degree air to 70 takes a lot of energy. The closed system of an OAK fed home means that the air in the room only needs to be heated once and then just maintained. I've never had condensation or cold air issues from my OAK even when weather has been in the teens. Yes, the oak pipe feels cold to the touch.

Like you said MSG, there's a lot of heated debates already and we don't want to revisit them. Oh, one more thing, my OAK actually spewed air into the home like a mini-chimney vs. resisting flow. The small amount of air needed by the stove is more than supplied by even the longest allowable OAK plumbing runs.

As far as making it look nice I would paint it to match the stove pipe, route it low and as short as possible, and then trim it out at the wall with some sort of beauty ring like the ones you see where a gas appliance flue leaves the room usually a stamped tin. The outside termination can actually be a screened dryer vent with the flap removed. The vinyl siding should easily accomodate a dryer vent outlet. The pellet stove folks will likely have a trim ring for the 3 or 4" oak ducting that will trim it out nicely.
 
If you do decide to install the OAK, make sure you install the outside vent lower than the stove. My stove is in the basement and I had a long run of pipe for the OAK up the concrete block and out the sill plate and found out cold air really likes to dive down and push into the stove which I think screwed with my burn times. I tried dampers and elbows trying to slow it down and it didn't work so I took it off.
 
Highbeam said:
Rats, and with that rear exit stove setting so far from the wall the area will look like an engine room. I think that the fireview would look way better without the OAK in a freestanding setup.

If room air is at 70 and outside air is at 20 then that's only a 50 degree difference to a 1000+ degree fire. No problem and maybe better since the colder air is more oxygen rich. Constantly heating the infiltrating 20 degree air to 70 takes a lot of energy. The closed system of an OAK fed home means that the air in the room only needs to be heated once and then just maintained. I've never had condensation or cold air issues from my OAK even when weather has been in the teens. Yes, the oak pipe feels cold to the touch.

Like you said MSG, there's a lot of heated debates already and we don't want to revisit them. Oh, one more thing, my OAK actually spewed air into the home like a mini-chimney vs. resisting flow. The small amount of air needed by the stove is more than supplied by even the longest allowable OAK plumbing runs.

As far as making it look nice I would paint it to match the stove pipe, route it low and as short as possible, and then trim it out at the wall with some sort of beauty ring like the ones you see where a gas appliance flue leaves the room usually a stamped tin. The outside termination can actually be a screened dryer vent with the flap removed. The vinyl siding should easily accomodate a dryer vent outlet. The pellet stove folks will likely have a trim ring for the 3 or 4" oak ducting that will trim it out nicely.
Click to expand...

Ok you got me :p, the only time i have seen them condensate is one of my customers had a very large aquarium in the same room as the stove and the humidity was high. It was pretty cool, but it runed the hardwood floors below the pad where the stove was installed. As far as the temp thing, thats an interesting take on it. Im not sure how much more o2 rich cold air vs warm air is, but that is for sure an interesting take. I figure, lets stir the old OAK pot! Thanks for Highbeam!
 
Ha! we can wait for Nof60 as he seems pretty passionate about his OAK, mostly to keep the humidity up in the living space as I recall. I think it is neat in an engineer sort of way but not sure of actual added value in my situation, well, other than the permit which would have been failed without the OAK hookup but thats a local AHJ situation.

I don't think a cat stove really runs that much air up the stack due to it having an actual intake damper vs. the non-cat that only allows you to partially throttle the primary air and then has wide open secondary air all the time.
 
im really not that passionate about it lol, just like to be educated so i can help my own customer base. Anytime i can learn something new it helps with qualifying every situation i come across with my clients. After all, if i can sell my self on outside air kits i can make a extra add on sale that i feel good about. As for now, i just choose to loose that business unless its required by law or the situation really really calls for one. The manufactures always hammered us NOT to sell them, especially Jotul. Old habits are hard to break.
 
I really think the Oak debate will go on forever. I wonder if that cold air coming in effects burn times and cools the stove off faster at the end of the burn cycle, I noticed it did for my setup, but my OAK was too high above the stove.
 
Slow1, My OAK is installed down through the floor directly behind the stove, then horizontally out through a rear basement wall where it is terminated on the outside with a heavier duty drier vent. The flapper in the dryer vent was removed and replaced with 1/4" rodent screen which is siliconed in place. I pack the dryer vent hood with insulation in the summer months to prevent infestation by bees and other unwanted creatures. The 4" OAK dryer vent in the basement is wrapped with fiberglass insulation to prevent heat loss and condensation with the aluminum pipe. The entire installation looks good.

Do not yet know how it works because I do not yet have my new PE Spectrum. This should be installed and burning by mid-August.

I was the general contractor when my house was built in 2004. It is heavily insulated and tightly wrapped with Tyvek. All Tyvek seams were taped. All visible seams and holes in exterior walls are sealed with silicone caulk so the house is very air tight. The OAK made sense to me because it provides a "path of least resistance" to air being used by the stove. I did not want the burning stove to suffocate while trying to suck air in through bathroom vents, dryer vent, doors, windows, electrical outlets, etc. If the OAK was not installed I would be afraid all the air being pulled through various small openings in the shell of the house would create cold drafts as it rushed to the stove.

By mid to late August I will know how well it works.

Good luck.

John_M
 
I'm totally clueless on the subject, but do the HRV's (heat recovery ventilators) you see now on new houses take the place of OAKs? I would think it would be more controlled than just a hole in the wall, especially if they can equalize inside and outside pressures.
 
The EPA has too many guidelines.

If you want to exchange your house air for outside air then there are devices like the HRV to do that. If you want an uncontrolled leak then you can open a window. If you want a situation where your solid fuel burning appliance will always have sufficient combustion air and is not affected by the homes air pressure then get an OAK. There is some benefit to having completely independent air systems for each appliance including your home. Notice how these new gas furnaces have outside air intakes? Also the coaxial direct vent pipe for gas stoves? Even water heaters now have the intakes outside.
 
cycloptic pendulum said:
Highbeam said:
The EPA has too many guidelines.

If you want to exchange your house air for outside air then there are devices like the HRV to do that. If you want an uncontrolled leak then you can open a window. If you want a situation where your solid fuel burning appliance will always have sufficient combustion air and is not affected by the homes air pressure then get an OAK. There is some benefit to having completely independent air systems for each appliance including your home. Notice how these new gas furnaces have outside air intakes? Also the coaxial direct vent pipe for gas stoves? Even water heaters now have the intakes outside.
Click to expand...
OAKs are affected by wind direction. gas which dont stink when flue leaks has a stringent code which tends to repeat "non-airtight construction" in the specs. CODECHECK book @ HD is a grreat reaD
Click to expand...

The OAKs are not affected by wind any more than your chimney is. That's more bad woodheat.org info regurgitated here. Show us your experience. If you install the OAK to a vented crawlspace then wind couldn't possibly be an issue.
 
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