AF Integra Insert - OAK Necessary?

[RKBAGUY]

Been seeing a lot of discussion about OAKs and didn't know what the heck that was until a recent post. I have an Integra installed in an existing masonry fireplace. Should I be looking for a way to get fresh air into the stove or is it alright as-is?

 

[briansol]

its not required, but IMO, totally worth it. first year with my oak after 4 years without it, and it makes a big difference. way less drafty house, i'm burning lower than I usually do this time of year too.

I got a 2-story cap from swilliamson's PSS. 1st floor is the intake, top floor is the exhaust, separated by a divider so the oak gets clean air. All in the chimney up and out.

 

[RKBAGUY]

Interesting. I wouldn't think it'd make that much of a difference, but I guess it's something I'll have to try. The challenge in my case is that I'm working within an existing masonry fireplace with a 12' chimney. Maybe next year.

 

[PELLETCONVERT]

Just had an install done, and they ran the OAK , in the same 8 inch pipe as the exhaust , only goes up about 6 ft
(replaced a free standing wood stove)

 

[RKBAGUY]

Not an option for me - I'm working with 3" straight pipe all the way up. I'll probably look into running a second line for the fresh air down the chimney next season.

 

[briansol]

The basic concept is this--

fire uses O2.
your house quickly runs out of it.

without an OAK, the stove draws in fresh air from all the nooks and crannies, creating cold drafts everywhere in the house. (negative pressure)
with an OAK, the stove has all the air it needs, and the room blower acts sorta like 'max ac', recirculating warm house air through the convection instead of trying to constantly fight with the cold air that keeps leaking in.

 

[bdaoust]

The basic concept is this--

fire uses O2.
your house quickly runs out of it.

without an OAK, the stove draws in fresh air from all the nooks and crannies, creating cold drafts everywhere in the house. (negative pressure)
with an OAK, the stove has all the air it needs, and the room blower acts sorta like 'max ac', recirculating warm house air through the convection instead of trying to constantly fight with the cold air that keeps leaking in.

Would that be the case even if the stove is in the basement? So, the stove is sucking in cold air from the upstairs as well? I always wondered if I should invest in an OAK with my basement P68.

 

[briansol]

absolutely. you may feel a lot of the air movement in a the stair case-- cold air at the floor, hot air up top.

it can only get better, it won't make anything worse if the fire is burning air from outside. It's safer too, no worry about depleated oxygen levels, and if the power goes out, there's less chance for smoke to back-out the intake into the house (which is also why you need to use non-combustibles for intake air too)

 

[bdaoust]

So, not sure if this something I could (or would want to) do myself.

Having said that - what is a rough estimate of having a installer do this?

 

[briansol]

It really depends on your house set up and where your stove is more than anything. I went up my flu along side my exhaust to a custom cap. Others go out through a wall.

parts are a couple hundred bucks probably (a thimble, a run of pipe, cap, etc etc).

 

[skibumm100]

I agree that an OAK is a good idea. Keep in mind that the older Austroflamm Integra air inlet pipe where the air flow sensor is located is not hard piped to the OAK connection on the back of the insert. There is a sizeable gap. This would allow an OAK to be helpful if the house is under negative pressure.

Sorry but I have to wave the BS flag on a stove depleting oxygen levels inside your house. Can't happen. The stove sucks air into it, not just oxygen. Air contains nitrogen, oxygen, CO2, etc. The fire consumes some of the oxygen during combustion, and exhausts through the flue what it pulled in (air) minus some of the oxygen used for combustion, plus combustion by-products (CO, CO2, H2O, etc). It does not selectively suck the oxygen from the room. The air that the stove uses has to come from somewhere. It either comes through your OAK or it comes through cracks or gaps in your houses exterior, windows, doors, etc. The oxygen content of the air in your house will not change unless you have an open fire in the middle of you living room. In that case, it's time to leave. Unless your flue is exhausting into your house, you have nothing to worry about.

 

[Mt Bob]

If you are not running stove 24 hours a day,you will have a big cold air leak into the house,per skibumms note about the gap in the inlet tube.On the older ones oak was considered optional.Bob

 

[briansol]

I agree that an OAK is a good idea. Keep in mind that the older Austroflamm Integra air inlet pipe where the air flow sensor is located is not hard piped to the OAK connection on the back of the insert. There is a sizeable gap. This would allow an OAK to be helpful if the house is under negative pressure.

Sorry but I have to wave the BS flag on a stove depleting oxygen levels inside your house. Can't happen. The stove sucks air into it, not just oxygen. Air contains nitrogen, oxygen, CO2, etc. The fire consumes some of the oxygen during combustion, and exhausts through the flue what it pulled in (air) minus some of the oxygen used for combustion, plus combustion by-products (CO, CO2, H2O, etc). It does not selectively suck the oxygen from the room. The air that the stove uses has to come from somewhere. It either comes through your OAK or it comes through cracks or gaps in your houses exterior, windows, doors, etc. The oxygen content of the air in your house will not change unless you have an open fire in the middle of you living room. In that case, it's time to leave. Unless your flue is exhausting into your house, you have nothing to worry about.

Of course, it's a bit 'dramatic'.

But it is for this very reason why mfg'ed homes and mobile homes require an oak for CO, and also why putting an appliance in a bedroom is illegal.

it's not the fire hazard... its the o2 hazard.

 

[skibumm100]

I respectfully disagree. A closed stove with induced draft fan and tight flue cannot reduce the O2 levels inside a building.....can't happen. Outside air is required in mobile homes and manufactured homes because the HUD code says it has to be there. It doesn't have anything to do with consuming oxygen in the room. Mobile homes and manufactured homes were assumed to be "tighter" than you average stick built house. The hazard in a tight house (with wheels or without) without an OAK is poor combustion due to insufficient draft (too little combustion air). This would lead to higher CO in the exhaust gases and possible hazards associated with leakage or backdrafting (due to low NET draft) into the living area.

You wouldn't want a stove in any confined area....like a bedroom. As an aside, I don't think you would want one in a bathroom either, but I don't know of a law against it. A pellet stove is an induced draft appliance. I creates draft with an exhaust fan and, in the case of a vertical flue, additional natural draft. As long as the flue doesn't have a restriction (like a damper) and the fan can produce enough draft, all of the combustion gases (with the lower O2 content) go out the roof. The room O2 concentration stays the same.

I've made my point. I'll shut up now. ;-)