POLL....Outside Air Kit (OAK).... Do you have it?

[thechimneysweep]

Treacherous & High Beam, you're both right.

There is no question that air evacuation caused by chimney updraft can cause cold, dry outdoor air to be drawn in through cracks and other openings in the house's shell, adversely affecting heating efficiency and the comfort of the occupants.

What originally gave birth to the Washington State legislation, however, were health issues that can result in tightly built houses, where the same air evacuation by the chimney can overcome the less-powerful outflow from other combustion devices in the household, such as gas furnaces and water heaters, and drag the colorless, odorless and poisonous exhaust from those flues back down into the breathing space.

The wording of the law as eventually enacted leaves room for interpretation by the state's individual code authorities. Most of them have chosen to require outside air in all new wood stove & fireplace installations, one reason being it can be difficult to judge the relative leakiness of a given home. I'm told that King County, where BG lives, only requires outside air in newly constructed houses.

 

[Highbeam]

I would not be surprised to see installations without the required OAK in WA. You and I probably know more about installing woodstoves than your typical inspector. I actually asked my inspector and he confirmed that he would have failed me.

So here's the deal, just do it. Nothing to lose, something to gain. If you don't like it then you can plug it. I have a couple photos of mine in my signature link.

 

[Milton Findley]

My gas furnace has an OAK, coming in to the intake. It is not big enough to keep the burner happy, so I leave the cover off and when it is going, it uses both outside air plus inflow air.

No matter what is going, wood stove, bath vent, hot water heater, there is always air flow into the house through this three inch PVC pipe according to my incense sticks. Even now, with nothing going, there is inflow through the pipe.

The point is that my nearly seventy year old house has plenty of ways for air to get in and out and it does. It will never be a problem around here.

But it is true that I am both lazy and cheap.

 

[Treacherous]

Kittitas County has been fairly lax in my experience so not likely it is enforced much if on the books. I'd be surprised if there were more than 1 or 2 inspectors in the county now. I remember only one back in the early 2000's. He joked to me about some building plans being filed away in the courthouse that were on napkins. I'm sure this has changed over the decade though. I don't have any gas appliances in cabin either so no combustion competition there.

Highbeam: It would be a harder install for me. I'd have to bust through my old brick fireplace pad. I suppose some type of masonry cutting tool would go through it though.

 

[North of 60]

There was nothing for me to click on for the poll selection either, regarding climate,conditions/humidity control. Humidity control was my issue. Less humidifier run hours= lower electrical bill. Easy $50 a month. No more frost build up at the doorways at -40 either. It must be my imagination since Gulland never mentioned it. :roll:

 

[Green Energy]

I have a funny story about OAK and my permit inspector. I did my own hearth mounted installation with a new T and flue liner. I had to add a hearth extension to get my 18" front clearance. When I had the permit inspector come out, I though he might come up with something on my hearth extension.

But I did not expect that he would tell me that the installation would not meet code because I did not have an OAK. The code here basically says that the installation must be per the manufacturer's instructions as provided in the install manual. I had meticulously read the US/Canada section of the Jotul manual and it did not say anything about requiring an OAK. So when I challenged the inspector about what is required, he took my manual and found a section where it said that an OAK should be used in tight houses. After arguing that my house wasn't that tight and that I am a licensed professional engineer that understands about combustion air, it wasn't looking good. The inspector was standing his ground.

All of a sudden, I had an epiphany - show him the cat door. I took him to the other side of the room and showed him the cat door built into the window. He said, "barometric damper," I said sounds good to me. And I got my permit.

BTW, after he left I looked at the manual cause I do not remember the paragraph that he was citing. I found it in the UK section and it was more definitive about OAK in "tight" houses. I was surprised that the US/Canada section was different than the UK section.

Also, Highbeam, et al, are correct. No reason not to put in an OAK. My excuse: did not want to core drill a hole in the floor of my fire place (lazy or cheap). Results: draft still works fine once the stove is going. Even without the cat door, combustion air would be pulled from the kitchen exhaust fan duct, or bath room exhaust fan (if they are not on).

 

[CountryBoy19]

Not really any of the above options.

My zc fireplace had to have an OAK, it was designed to have one on it.

Yes, I have an OAK, but I did break the installation guidelines and vented it into the attic space (with proper spark arresting for any reverse draft events). I wasn't about to run it anywhere else because the run was going to be too long, too complicated, or not an ideal location for an OAK.

 

[turbocruiser]

As mentioned already, the poll leaves out the option for "no" but I initially didn't install the OAK for a few reasons. Before I list those reasons I should say "I initially didn't install" because in my particular place it'd be incredibly easy to install the OAK later if needed and I factored for that when I was making my "initial" decision.

Anyway, after consulting with a wide range of "experts" including regional inspectors, I chose not to because:
1. Not required by regional code.
2. Not recommended by the two inspectors I talked to (to be totally fair though they also all stated it wouldn't hurt anything at all to have the OAK).
3. I have an extremely high efficiency (95%) gas furnace with its own intake (that is totally sealed to the unit) and electric appliances otherwise throughout the house so no other source of gas operated combustion.
4. I have an exterior door exactly six feet from the stove and although it is an energy efficient model I can purposely put a little leak in the door by simply throwing the deadbolt and releasing the latch.
5. Although our house is well insulated I know it isn't airtight and I'd actually rather have some air exchange through existing leaks I haven't already handled; I'm convinced that the condensation that occurs naturally when warm air meets cold air needs some natural ventilation so the little leaks I haven't handled yet are simply serving that purpose. Seriously though it was mostly reasons 1-4 above that made me initially not install the OAK. If I find the stove is struggling for more air, I can install the OAK in an afternoon easily.

 

[MasterMech]

My Earthstove has one that's hidden in the pedestal and I have the kit for the Rangeley that I fully intend to hook up. The dealer looked at me like I'd asked him for nuclear launch codes when I said I wanted to order the kit. I have a whole house fan that the wife likes to use every now and again just to exchange the air in the house. She tosses open a couple windows, turns the fan on super-low and runs it for about 5-10 mins.

 

[turbocruiser]

I'm not sure if this is too drastic a detour to the thread (and if so I'll start another one if others prefer) but it seems that the several models of modern stoves I shopped (including my Regency) just have the OAK terminating into an open area under the damper. In other words it isn't sealed to some flange which would prevent the OAK from just constantly leaking outside air to inside air. That first made me wonder why anyone would design this device that way. Then that made me wonder whether there are any OAKs that include an internal damper of some sort so that they are not able to constantly leak air? Thanks.

 

[thechimneysweep]

This is one reason code requires that outside air terminations be located below the point of connection to the stove. In most cases, old Mom Nature will ensure that cold, high-density outdoor air will not travel upward through the intake pipe unless it is being drawn in by the chimney updraft. That updraft will draw the cold air into the firebox and, eventually, out the top of the chimney, so it doesn't flow into the room.

 

[turbocruiser]

This is one reason code requires that outside air terminations be located below the point of connection to the stove. In most cases, old Mom Nature will ensure that cold, high-density outdoor air will not travel upward through the intake pipe unless it is being drawn in by the chimney updraft. That updraft will draw the cold air into the firebox and, eventually, out the top of the chimney, so it doesn't flow into the room.

That makes sense but I basically think that I'm only seeing one part of the connection to stove. There must be some sort of "pan" or something to seal to the bottom of the firebox because without that even though cold air is not necessarily going to go "upward" there would be so much leakage it would be wasteful to the extreme. I looked all around on Regency's site but couldn't find a picture of the OAK that goes to my stove but I'm sure it is more than just a metal flex hose going under the unit! Does anyone have a picture of a Regency Stove OAK ???

 

[remkel]

I have a funny story about OAK and my permit inspector. I did my own hearth mounted installation with a new T and flue liner. I had to add a hearth extension to get my 18" front clearance. When I had the permit inspector come out, I though he might come up with something on my hearth extension.

But I did not expect that he would tell me that the installation would not meet code because I did not have an OAK. The code here basically says that the installation must be per the manufacturer's instructions as provided in the install manual. I had meticulously read the US/Canada section of the Jotul manual and it did not say anything about requiring an OAK. So when I challenged the inspector about what is required, he took my manual and found a section where it said that an OAK should be used in tight houses. After arguing that my house wasn't that tight and that I am a licensed professional engineer that understands about combustion air, it wasn't looking good. The inspector was standing his ground.

All of a sudden, I had an epiphany - show him the cat door. I took him to the other side of the room and showed him the cat door built into the window. He said, "barometric damper," I said sounds good to me. And I got my permit.

BTW, after he left I looked at the manual cause I do not remember the paragraph that he was citing. I found it in the UK section and it was more definitive about OAK in "tight" houses. I was surprised that the US/Canada section was different than the UK section.

Also, Highbeam, et al, are correct. No reason not to put in an OAK. My excuse: did not want to core drill a hole in the floor of my fire place (lazy or cheap). Results: draft still works fine once the stove is going. Even without the cat door, combustion air would be pulled from the kitchen exhaust fan duct, or bath room exhaust fan (if they are not on).

If I remember correctly, the manual for my F600 actually states that Jotul does not condone the use of an OAK with their stoves. I could go back and read it again, but that would be too simple....