COLD AIR EXCHANGE EXPLANATION???

GeHmTS said:

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.

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OK...I'll hop in with a serious post, what I've learned from HVAC people, other info.

Make up air is not only a factor with pellet stoves. Anything that is using any type of combustion, or pulling air for it's use (i.e. an electric clothes dryer) is consuming air contained within the house proper. This includes basements, attics, attached garages, etc.

This can cause problems no matter how loose or tight the house is.

If the house is tight, minimal leakage from the outside, using interior air for one device could affect the performance of the other devices, starving those machines of the air they need.

If the house is loose, using interior air will pull outside air into the house. In Central MA, dead of winter, it could mean replacing quite a bit of heated 65 degree interior air with 10 degree outside air. I've got a Harman Accentra FS, I'd like to see what the CFM rating is on the combustion fan, compare that to room size, etc. Lets go on the low end: A 10 CFM fan (and I'm betting this is on the low side, but I do not know) vented to the outside will replace all of the air in a 15' X 15' X 8' every 3 hours. Seems like quite a waste of air we pay to get to temperature.

Installing an OAK will provide the stove with the needed resources for proper combustion of the pellets without either (1) possibly starving the other appliances or (2) wasting already heated interior air, quickly moving it to the outside.

Not having proper combustion air increases costs of pellet stove use (we've seen the posts on trying to fine tune the burns, trim the air, so that pellets are not wasted, or to get maximum heat from each bag), also decreases the efficiency of gas water heaters, gas and oil furnaces, etc. These effects are not readily seen...the utility bills may go up a bit, it may take a bit longer to reach room temp, oil burners may need more frequent cleaning.

What is noticed easily is the cold draft wafting through the house. Getting an OAK in place takes care of that appliance itself, decreasing the need for the outside air to come in to service the needs of that appliance. Adding an OAK to one device could add to the efficiency of other appliances in the household. Adding an OAK immediately increases the comfort potential of that device.

I'm still amazed that most of the stove dealers and installers will try to talk you out of it...I can certainly see it would add to the time and expense (minimal) of the installation, but the benefits of an OAK far outweigh the problems of getting it in place.

At least I think that's what they told me. Put me to sleep too.....

BrotherBart said:

And as any drag racer will tell you, the colder and denser the air the more complete the combustion.

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This brings up a whole 'nother bag 'o worms...

The colder and more dense the air in a compression situation (automobile engines, aircraft engines, etc) the better it will dyno. I know that installing a NOS on a supercharged Mini Cooper S will get you into a lot of trouble. In many ways. Also by running a CO2 bath over the supercharger, "freezing" the intake air.

That we're bringing in cold air to a device that emits some of its heat by radiating it off the metal enclosure may in fact be decreasing the efficiency, but the balance is far in favor of keeping interior heated air heated, and reheating already heated interior air by way of the distribution blower.

Pete Zahria said:

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

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I've been staring at this post like a monkey doing algebra. How is having an OAK the same as leaving a window open???

TimfromMA said:

I've been staring at this post like a monkey doing algebra. How is having an OAK the same as leaving a window open???

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It's not the same, it's the exact opposite. IMO.

To the OP, or anyone else reading this thread, install the DAMN OAK/FAK!

BrotherBart said:

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.

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Just teasing a bit, Bart. All in good fun. Go have some egg nog.

GeHmTS said:

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.

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My plan was to draw it from the attic. Still might, but everything is working fine with nothing attached to the stove inlet so far.

Don't forget that your OAK should end with some kind of screened cap...not only to keep out the little fellows like Chippy's but even hornets/wasps. Good to add the annual....Check the OAK for obstruction/clean screen.

womaus said:

OK...I'll hop in with a serious post, what I've learned from HVAC people, other info.

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Well said ... I've tried that type of post too and you still get folks that don't get it or won't try it. It always baffles me about installers not insisting on putting in an OAK too. When we first installed our stove, it was without an OAK. Reading the discussions here, I installed one about 2 weeks later. Glad I did!

Lake Girl said:

Well said ... I've tried that type of post too and you still get folks that don't get it or won't try it. It always baffles me about installers not insisting on putting in an OAK too. When we first installed our stove, it was without an OAK. Reading the discussions here, I installed one about 2 weeks later. Glad I did!

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Ditto My Enviro dealer said: No...not needed. My owners manual (and I can post if needed) says "strongly recommended......
Bill

bostonfan49 said:

Ditto My Enviro dealer said: No...not needed. My owners manual (and I can post if needed) says "strongly recommended......
Bill

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Harman manual: ". . . [the company] strongly recommends attaching outside air in all installations, especially lower level and main floor locations." [bolding is mine]

TimfromMA said:

I've been staring at this post like a monkey doing algebra. How is having an OAK the same as leaving a window open???

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It was actually sarcasm. I'm sorry some missed it...

Explanation.
If you do not run an outside air intake to your stove, it is the same as
running your stove with a window open.

Meaning that the total cubic feet of air coming in through every
nook and cranny, is equal to leaving a window opened.

Meaning, if it were me, I would opt for the outside air intake,
rather than the open window.
I had to bore through a masonry wall to install mine,
but I thought it was worth it, as I do not want to have the equivalent
of an open window all winter..

Dan

Pete Zahria said:

It was actually sarcasm. I'm sorry some missed it...

Explanation.
If you do not run an outside air intake to your stove, it is the same as
running your stove with a window open.

Meaning that the total cubic feet of air coming in through every
nook and cranny, is equal to leaving a window opened.

Meaning, if it were me, I would opt for the outside air intake,
rather than the open window.
I had to bore through a masonry wall to install mine,
but I thought it was worth it, as I do not want to have the equivalent
of an open window all winter..

Dan

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I liked it better when it sounded snarky.

Pete Zahria said:

It was actually sarcasm. I'm sorry some missed it...

Explanation.
If you do not run an outside air intake to your stove, it is the same as
running your stove with a window open.

Meaning that the total cubic feet of air coming in through every
nook and cranny, is equal to leaving a window opened.

Meaning, if it were me, I would opt for the outside air intake,
rather than the open window.
I had to bore through a masonry wall to install mine,
but I thought it was worth it, as I do not want to have the equivalent
of an open window all winter..

Dan

Click to expand...

Ok, this ape finally solved the equation.

It's kinda like trying to get someone to try sushi. You have to twist the arm really hard and one they try it they love it.

On another note, if you are handy, most hardware store have 3" rigid aluminum dryer vent that works great. They will have elbows 90*, 45* and straight lengths along with bug proof end caps. This is what I used. I think I spent $12 all together. Screwed it together and rtv'd it. If your stove has a 2" inlet you might have to get creative with the adapter. Just remember it needs to be. Non flammable, so don't use those expanding dryer vent or any other dryer vent other then some kind of ridgid metal.

bostonfan49 said:

View attachment 170179 View attachment 170180 Don't forget that your OAK should end with some kind of screened cap...not only to keep out the little fellows like Chippy's but even hornets/wasps.

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I'll be covering the inlet once the heating season is over.

And then I'll try to remember to uncover it when the next heating season begins.

OAK only makes sense to me and none makes no sense to me, so I installed it. My dealer said I didn't need it and they almost never install them on their installs ( we installed the stove ourselves). We ran the first year without it, the stove ran fine but we had drafts everywhere in the house almost. Big difference with the OAK installed as I already mentioned further back in the thread.. The point here, is I don't know why some dealers don't recommend it either. Now since my dealer doesn't install OAK on their installs, they also didn't have a kit for the P61. So I ordered my supplies online and they lost a sale to a customer who would have been glad to get what he needed in a one stop shopping spree, vs piecing it together. So not only does it seem counter intuitive to not run an oak but it also seems counter intuitive, to me, that the dealer wouldn't stock it, recommend it, and not install it as standard policy..

alternativeheat said:

The point here, is I don't know why some dealers don't recommend it either.

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I agree.
You do not have to say that you absolutely "need" it...
Just that it is better if you use one.

Dan

. . . but wait! If I pull -20 degree air from my OAK into burn chamber, won't that cool down my fire? Won't my pellet stove not produce as much heat?

Well?

doghouse said:

. . . but wait! If I pull -20 degree air from my OAK into burn chamber, won't that cool down my fire? Won't my pellet stove not produce as much heat?

Well?

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this thread already belongs to arm chair physicists and nascar aficionados...

[

BrotherBart said:

One thing about an OAK is that in a power failure it takes CO coming out of the intake into the living space out of the equation. One pellet stove vendor used to have this in their ads but took it back out of them for some reason.

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Please give a better explanation here? Takes CO coming out of the intake? Huh?

PWash said:

this thread already belongs to arm chair physicists and nascar aficionados...

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There's not a lot to debate about negative air, positive air. The Nascar stuff, well, I don't know. I'm more of a SCCA guy myself. I just don't understand rountidity rounds. And more rountidity rounds. And more.

What's not to understand? Houses these days are tighter. For a reason. Efficiency.

Throw something into a house using resources within the house (wood stove, pellet stove, clothes dryer, your own kids, guests from Venezuela) it's going to cost you money. The idea is to mitigate the damage.

An OAK will at least take care of the pellet stove. The others, well, you're on your own.

BrotherBart said:

It is a hole in the stove. Fire goes out. Pellets smolder. Smoke takes the path of least resistance.

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Pellet stoves, if running correctly, continually push air through the system until the temperature is so low as to not allow smoke to get into the inside environment.

Having a recommended vertical stack for the exhaust will help to alleviate the potential of smoke getting into the inside environment in the event of a power outage / fan failure (I know this from firsthand experience, multiple time while setting up my "bought used with a bad board" stove). The heated vertical stack is the path of least resistance. Just like a fireplace chimney.

Yes, it's a hole in the stove. My hole in my stove has a flapper that is designed to allow air to come in...but not go out.

And dammit that's whats keeping the cockroaches and rats in my house. I hate that flapper.