COLD AIR EXCHANGE EXPLANATION???

[Blackmagic]

My wife and I have a 24 year old pellet stove that gave up the ghost last week.
We are looking at new pellet stoves and have talked to (2) local dealers/installers.
Can some of the members here, please explain (in real simple terms),
what a "Cold Air Intake" on the new pellet stoves is and what it does?

I've hear talk like, "Negative Pressure", "depends on what type of house you have" ect.

We currently live in a single level Ranch House in California, that was built in 1974.
It has no basement, and I'm sure it does not have tight seals around the doors ect.
It has a fireplace that has been "bricked up/sealed", with a 3" diameter inlet, that our current pellet stove connects to.
I goes up into a regular chimney with no "center tube".
My F-I-L, says it should be alright as long as we clean the chimney every year.

So if a new pellet stove is cost prohibitive, a I buy a used one,
(or a less expensive one at Home Depot), and just vent it into the chimney, is that OK?

Now I assume that many installers may cringe at my question,
but we've been running my old "Jamestown J2000T" stove, like this for 3 years.

Any help, info, links would be appreciated.
I'm a beginner here, so the simpler.....the better.

 

[3650]

It provides air to the burn pot from outside the house via a pipe of your choice. If it isn't ducted to the outside of the house and left to draw air from inside the house, it pulls air in to your house from every crevice and air leak your home has. This is cold air from outside. If you have a drafty house there will be a constant cold draft being pulled in and up through the chimney. If your house is tight it probably wont be as noticeable. If you provide outside air via some sort of pipe to the firepot there will be no air being pulled from inside the house only outside and therefore no drafts in the house.

When I first bought my Quadrafire MT Vernon I didn't use and outside air kit. I ran that stove wide open, my house was constantly 80 to 85 degrees and yet I was freezing. I have a very drafty house. I just thought pellet burning was a bunch of bull and that pellet burners on these forums were full of it. Then I bought a US stove Window pellet burner to help heat the house. I put it in the back of the house. When I ran it alone the house was so much warmer. I couldn't understand why this tiny little stove was keeping the house warm, then it dawned on me. This little stove pulled air from outside the house to the burn pot automatically. I slapped an outside air kit on the MT Vernon and it was like night and day. There was so much warmth in the house. I no longer had to run that big stove wide open, in fact I ran it on low most of the time (except for cold snaps).

There are a lot of variables whether you need on or not, how tight your house is, how much wind you get, how cold your climate is there. I use a Cumberland 3650 now and my sister has an identical stove. I use an OAK and she doesn't. My house, very drafty, uninsulated, old, no wind break out on the prairie. I burn on low a lot unless the wind kicks up or a cold snap. Fairly comfortable. She lives 8 miles from me in a city with fair amount of wind break. Her house is very tight and well insulated. No drafts, burns on low a lot, comfortable house. There is much more to it as well this is just my experience. If I was to move to a different home I would still use an OAK, even if I moved into my sisters home. I am a AOK believer.

 

[bags]

Hook it up and thank yourself later.

X2 with what 3650 says. Do a bit of research and it is self explanatory. Cold air seeks out warm air and tries to equalize the pressure. The OAK pulls that cold air into the stove thru a sealed hose / pipe and goes directly into the combustion area. Therefore it has what it wants air wise so it is not taking the already heated air from within your home which is then replaced by cold outside air infiltrating any and ALL little air leaks in you homes envelope. Leaks are everywhere even in tight houses, but when the OAK delivers air into the stove the pressures are not competing like they do without an OAK set up.

Some argue against OAK's All I can say is go educate yourselves. It is simple physics of air exchange rates and negative and positive air pressure. I'll make it very simple. For every cubic foot of air that is used by a non-OAK'ed stove for combustion which it sucks from within your cozy house (already heated inside air) another cubic foot of COLD outside air comes in to balance that. It is a vicious cycle and there really is not an argument otherwise. Just a simple fact of how air moves, physics, and thermo dynamics. Do your self a favor and research that, do not let a dealer or anyone sway you otherwise, hook up the OAK and be very happy you did.

Oaks are not very hard to do and do not cost much money. What is spent in time and money gets paid back quickly in more ways than one. The OAK debate has been beaten to death here so read up on it and form your own educated thought about it. Use the search bar above and just plug in: To OAK or not to OAK, Good Luck! Be smart.

 

[Wilbur Feral]

3650 gives a good explanation and experience. To say it slightly differently, an Outside Air Kit", or OAK, as we often call them, just brings the air needed for combustion directly from the outside, to the burn chamber of your stove. You must have air for combustion to occur, and if it doesn't come as colder, drier air from outside, your stove will pull it from the inside of the house. But you have already paid to heat that inside air, and maybe to humidify it. So considering the amount of air the combustion fan (blower) on your stove can move, that's a lot of paid-for, heated air to be used for keeping a fire going, and then pumping outside. Then, to make matters worse, that air that's being pumped outside must be replaced (because otherwise your house would end up with a vacuum). So cold air from outside gets sucked in from all around your house, anywhere there's even the slightest little crack. And you then have to heat that air, and maybe humidify it. It creates a nasty, expensive cycle of "accelerated air exchange" (paid for heated air being pumped outside and replaced by cold air that must be heated). You dramatically decrease this with an OAK, and that's why they make sense.

I can't really comment too much on your exhaust situation, except to say that it's less than ideal. Pellet stoves are designed to use a 3" or 4" exhaust, depending on the length of exhaust (there's a method to calculate the point where you need to go to 4" that I won't go into here). But going into a much larger chimney can allow exhaust gases to cool quickly, which can build up residue - some of it potentially dangerous - faster. There is also always the danger of your chimney not being well sealed, which can allow for carbon monoxide to enter the house. It's not ideal, may not be up to fire codes, and you need to consider that. And you should always have good fire (smoke) and carbon monoxide detectors.

 

[TimfromMA]

A pellet stove draws air in through the air intake, through the combustion chamber and then right out the vent. Imagine having a fan in your window blowing your heated home air right outside. This is precisely what a stove without OAK does. This air has to be replaced from somewhere and will get drawn in from all over the place creating drafts. Installing OAK will allow your stove to pull in combustion air directly from outside.

 

[bogieb]

3650, Bags and Wilbur have it pretty much covered as far as n OAK goes. There are several people on this forum that don't have an OAK who, for some reason, don't get cold drafts in their house. But I would think that they are exceptions and have unique circumstances that unless there is a comprehensive energy audit, we will never know the how's or why's.

My experience with a house that was not tight when I put in a stove (the house is tighter now, but very loose still compared to most houses).

Had the P61a in the basement professionally installed in early January of 2014. Even though Harman highly recommends installing an OAK for all occasions, they didn't. I didn't think much about it and figured the heat should rise easily and it would pull in air from around the sill, the door to the garage and around the frame of a couple of windows in the block foundation.

Well, it might have pulled air in from those places too, but when the stove was running, which it did 24/7 for the most part, on the main floor I could feel air coming in from every window, door, and even the walls. There were also other issues with the heat not rising, but add a wind chill to the mix, and it was uncomfortable. In March of 2014, after reading a bunch of stuff on the forum, decided to bight the bullet and self-install an OAK. Immediately the wind chill on the main floor went away (when the wind wasn't blowing anyway).

When I self-installed the main floor stove, I never even thought twice - I put in an OAK.

 

[Deezl Smoke]

Think of your clothes dryer. When it runs, you have a lot of air carrying the moisture out side of the house. That air has to come from somewhere. Usually it comes from the inside of the house. So as the dryer pulls air into it to carry the moisture out, the inside of the house will be drawn to a lower air pressure than the outside. Outside air will try to come in from any place it can. Down a chimney, in thru door seals or attic doors etc.

Clothes dryers, wood stoves, gas furnaces, pellet stoves.....anything that exhausts air to the outside of the house, require that air to come from somewhere. Many new construction houses in colder climates, will have a system that passes that warm exhaust air thru a radiator of sorts and has the new incoming air cross over it as it is piped directly to the appliances that use it.

On a pellet stove, you'll see two places to hook up piping to it. Usually a smaller diameter for the air inlet and a larger diameter for the exhaust. Both of them should be piped to the outside of the house. There are some requirements as to the distance that the piping terminations should be from each other and the types of devices installed on the ends of the piping, but they will vary depending upon your installation. You might check on the codes for your area on the exhausting of the stove. If you do not plumb it accordingly, your insurance may or may not have issues paying you should a loss occur.

IMO.

 

[prairyD]

This thread is particularly helpful to us, thank you! We have just purchased our first stove. We have a Castle Serenity and a vent kit. What we are unsure of is what we need and where to find the parts for the cold air intake. Any guidance would be most helpful. Thank you!

 

[Lake Girl]

What hasn't been mentioned, if you have an "air-tight" home, is that your pellet stove will not burn as well because it can't get enough air quickly enough from inside of the house. As mentioned above, there are many appliances that draw air from inside the house - clothes dryer, bathroom fan, kitchen fan, radon system. We had one forum member who had noticed a change in his pellet stove from the previous year. It had been installed without an OAK. Went through the stove top to bottom cleaning like a fiend and still no change. What changed? They had installed a radon remediation system which draws air out of the basement (where the stove was located). Installed an OAK and he was back in business. The stove was not getting enough combustion air quickly enough to get an effective burn

 

[rich2500]

This thread is particularly helpful to us, thank you! We have just purchased our first stove. We have a Castle Serenity and a vent kit. What we are unsure of is what we need and where to find the parts for the cold air intake. Any guidance would be most helpful. Thank you!

This is the kit you are looking for, available many places or some folks have put together their own set up with parts they sourced themselves
http://www.woodlanddirect.com/Dura-...4vs9UKjILqTAbuNSEyf5qias5nM2XA5CXaxoCDhXw_wcB

 

[prairyD]

This is the kit you are looking for, available many places or some folks have put together their own set up with parts they sourced themselves
http://www.woodlanddirect.com/Dura-...4vs9UKjILqTAbuNSEyf5qias5nM2XA5CXaxoCDhXw_wcB

This is helpful, thank you!

 

[bogieb]

This is the kit you are looking for, available many places or some folks have put together their own set up with parts they sourced themselves
http://www.woodlanddirect.com/Dura-...4vs9UKjILqTAbuNSEyf5qias5nM2XA5CXaxoCDhXw_wcB

That 2" is good for a lot of stoves that have a 2" OAK - it was for my former Hastings. However, if you have a Harmon, it has a larger air inlet at 2-3/4" (and newer ones have a 3") and you may want to make a 3" OAK out of 3" semi-rigid flex pipe and a 3" dryer vent hood to go thru the exterior of the house. However, many people run their Harman's fine on 2". My P61a runs better on the 3" I installed this fall than when it ran on the 2".

 

[alternativeheat]

Another thing not mentioned is if your original stove is still running at all your house will still benefit from oak, even with it. It's a stove, it eats air too ! But pellet stoves, unlike wood stoves, are force fed air so they draw harder on where ever the air supply comes from. So this isn't about new model stoves at all, it's about pellet stoves new and old.

I ran 3" metal dryer vent hose from my P61 up my chimney to the other side of the block off and insulation and immediately cut all drafts in the house down to a minimum. My suggestion ? Install the OAK..

 

[rich2500]

That 2" is good for a lot of stoves that have a 2" OAK - it was for my former Hastings. However, if you have a Harmon, it has a larger air inlet at 2-3/4" (and newer ones have a 3") and you may want to make a 3" OAK out of 3" semi-rigid flex pipe and a 3" dryer vent hood to go thru the exterior of the house. However, many people run their Harman's fine on 2". My P61a runs better on the 3" I installed this fall than when it ran on the 2".

They said they have a Serenity so that is the size kit they would need ,other stoves may require a larger size, my post pertained to their particular stove.

 

[Pete Zahria]

The easiest, and shortest answer is:
You can get the same result as an outside air intake connected to your stove,
simply by leaving a window opened, all the time....


Dan

 

[bogieb]

They said they have a Serenity so that is the size kit they would need ,other stoves may require a larger size, my post pertained to their particular stove.

You are correct, I should have paid more attention!

 

[Wilbur Feral]

By the way, for those keeping score at home, I think that's only the fourth "Do I need an OAK?" question of the year. I think we're running way behind. I blame the warm temps in the eastern US.

 

[womaus]

By the way, for those keeping score at home, I think that's only the fourth "Do I need an OAK?" question of the year. I think we're running way behind. I blame the warm temps in the eastern US.

Can someone direct me in the correct way to start a new "Do we need an OAK" thread?

I'd seriously like to help with making this forum all that it can be...

 

[Lake Girl]

Trying to stir the pot are you?

 

[womaus]

Trying to stir the pot are you?

Me? And did you really say "part"?

 

[BrotherBart]

One high point of this forum is that nobody gets harassed for asking a question that has been asked before. And always will be. If answering questions over and over bothers you, then stay out of the thread. Think I haven't answered the same ones a 100 times in ten years.

And cleaned out a few dozen threads where the OP was getting ragged on.

 

[womaus]

One high point of this forum is that nobody gets harassed for asking a question that has been asked before. And always will be. If answering questions over and over bothers you, then stay out of the thread. Think I haven't answered the same ones a 100 times in ten years.

And cleaned out a few dozen threads where the OP was getting ragged on.

I'm just having fun...

I think I was the first or second this year to ask about OAKs after I was getting very conflicting info from the stove stores and dealers I was visiting. This forum certainly made everything clear (though there is still a bit of difference in opinion...)

 

[Lake Girl]

Yeah I said part originally and hit edit... brain on auto-pilot

 

[womaus]

Yeah I said part originally and hit edit... brain on auto-pilot

I usually edit all of my posts at least twice. Stream of conciousness writing is not a great way of doing things....

 

[GeHmTS]

I don't need an OAK because I'm sure all my cold air is being drawn from the basement very close to floor level. Has anyone ever have an IAK (indoor air kit) where they are pulling from a lower level. I think it would work the same way.