Pacific Energy Med Insert: To use outside air or not?

[ProPain]

I have a Pacific Energy Medium sized wood burning fireplace insert.

This model is supposed to allow for one to use outside air for combustion.

Q. 1) Should I do this?

Q. 2) I see on the back of the insert a rectangular opening, but there is not mention in the manual about hooking it up to outside air.
Anyone done this and does Pacific Energy sell parts to do this outside air installation?

 

[karl]

I like outside air. As for parts, I don't know probably.

I have an ash box hangs down right where the air opening is. I took the ash box out and this left a hole down to the crawl space. This is where my outside air comes from. I don't have any plumbing on it.

 

[Oregon Fire]

My jotul has the option for outside air as well - this is code in some states. Most think it is a bad idea. You can have a gust of wind outside the house while you are loading the stove - this will push smoke/gasses into the home. Most here would recommend having the combustion air coming from inside the home...

As far as efficiency goes - pulling air from inside the home for combustion seems like a bad idea at first.... Until you think about what they deal with fresh air in newer "tight homes" - code in some states requires that the cooling/heating system pull in outside air via a damper....

jeff

 

[fossil]

If you want to use outside air for combustion, and the manual addresses this option, then there's more than likely an add-on kit available from the manufacturer for this purpose. Outside Air Kit (OAK), so far as I know is always required in a mobile home application, and might be required in any application in some jurisdictions. In Oregon, it's not required, but there's a tax credit available for installation of a listed/approved EPA woodburning appliance...but only if it's equipped with an OAK. An outside source of combustion air must be ducted and dedicated to the purpose...anything short of that, and any of us could just crack a window open and say, "See? I've got OAK!". Whether or not you want to do it (assuming it's not required in your application), is completely up to you. There are advocates and there are anti's. If you do a search on Hearth.com for it, you'll find some discussions about it, and if you Google it you'll find more. Have fun! Rick

 

[Todd]

This has been debated many times here. Do a search on "outside air" and you will get tons of info. I'm a fan of outside air, it just makes sence to me. Why burn the inside air and suck cold outside air into a home through cracks and leaks, seems inefficient to me. Outside combustion air pressurizes your house and pushes the warm air out towards the leaks. Also is a good idea if you have a tight home and your stove has to compete with other appliances for air.

Oregon Fire,
Do you have any evidence of smoke or gas backing up into anyones house because of an OAK? I would think you would need hurricane force winds to even come close to this happening.

 

[fossil]

...Outside combustion air pressurizes your house and pushes the warm air out towards the leaks...

Todd, I agree with everything you said except this...it can't be right. An OAK, properly installed, provides a little dedicated air duct from outside the house to the combustion air inlet on the wood-burning appliance. To "pressurize" your house, it would have to have some sort of fan in it (they don't) and the air would be entering your house "backward" through the stove or insert. An OAK may tend to maintain a good draft for a wood-burning appliance in an installation where the dwelling is very well sealed up (airtight), and it obviously is drawing the appliance's required air for combustion from outside the living space, so it's not air that you've already burned fuel to heat. But I can't imagine an OAK installation actually increasing the pressure in the house, under any circumstances short of something like sticking a leaf blower right into the duct outside. Rick

 

[Oregon Fire]

This has been debated many times here. Do a search on "outside air" and you will get tons of info. I'm a fan of outside air, it just makes sence to me. Why burn the inside air and suck cold outside air into a home through cracks and leaks, seems inefficient to me. Outside combustion air pressurizes your house and pushes the warm air out towards the leaks. Also is a good idea if you have a tight home and your stove has to compete with other appliances for air.

Oregon Fire,
Do you have any evidence of smoke or gas backing up into anyones house because of an OAK? I would think you would need hurricane force winds to even come close to this happening.

I have read that canada is considering changing their code requirements in regard to outside air supply in fireplaces and wood stoves. It isn't the great idea it seemed to be on the surface. I'll dig up some references and post them up for you.

jeff

 

[ProPain]

I thought maybe a Pacific Energy dealer would say if there is an actual kit from P.E. to hook up to the back side of
their med. insert. One installer said that he normally takes a diamond saw and cuts a slot through the fireplace brick and also the outside chimney brick, but he wanted me to find the kit to make it work.

 

[fossil]

I imagine that whatever OAK "kit" they might sell would simply consist of something (an adapter) that attaches to the stove in place of the block-off plate or whatever's there now, to allow you to figure out and install whatever it takes to get it hooked up to "outside". Rick

 

[thechimneysweep]

Pacific Energy's inserts are designed to burn outside air passively, through a rectangular opening in the rear panel. Introduce outside air into the fireplace, and that's what the PE insert will burn. In colder climates, the introduction of outside air into the area surrounding the insert might not be all that desirable, due to its cooling affect on the air convection plenum. In those cases, a knockout on the insert allows combustion of room air. It can be argued that direct connection of outside combustion air to the rectangular opening might be a good idea, but the adapter needed isn't available from the manufacturer. I have built one, using an aluminum liner top plate with a 4" collar and a sheet metal break. Basically, a rectangular box with an outer flange bolts to the air convection plenum, the bottom flange omitted in favor of a flat tab that slides under the insert (the rectangular intake opening is flush with the bottom panel). I'm not available to build another one, but your local sheet metal shop can fab one up for you: what you ask for is a rectangle-4" round adapter. Note: you'll need several inches of clearance behind the insert to make room for the adapter.

I have read that canada is considering changing their code requirements in regard to outside air supply in fireplaces and wood stoves.

You need to catch up on your reading. Canada stopped requiring outside air for every woodstove installation several years ago, based upon test data available at the time. If you're looking for a reference, you'll find it on the website of the man who spearheaded the change in Canada's outside air policy, John Gulland, at http://www.woodheat.org. In light of more recent information, The US requires outside air for all manufactured housing installations, and Washington State subsequently decided to require outside air for every installation in new construction.

I can’t imagine an OAK installation actually increasing the pressure in the house, under any circumstances short of something like sticking a leaf blower right into the duct outside.

Heated air expands, so a woodstove that isn't dragging outside air into the house for combustion causes positive pressurization.

 

[fossil]

I can’t imagine an OAK installation actually increasing the pressure in the house, under any circumstances short of something like sticking a leaf blower right into the duct outside.

Heated air expands, so a woodstove that isn't dragging outside air into the house for combustion causes positive pressurization.

I gotcha, Tom. Makes sense, so long as the OAK is tight to the stove, and the house is real tight, then the heated air inside the house wants to expand. Thanks, Rick

 

[ProPain]

<<<<Pacific Energy’s inserts are designed to burn outside air passively, through a rectangular opening in the rear panel. Introduce outside air into the fireplace, and that’s what the PE insert will burn.

Great info! Thanks Chimneysweep!

I was wondering if it were sufficient to just cut a hole in the back of the fireplace (about level with that back intake) instead of directly coupling the insert's air intake via a custom fabricated metal chase)?

I could do the bending of metal etc., but I am more concerned with getting it connected while at the same time connecting the liner. To execute both jobs while shoving the insert into the fireplace seems like a tough go.

 

[ProPain]

HERE IS WHAT PACIFIC ENERGY.s Techsupport REPLIED:

To: [email protected]
Subject: Tech Support Question from Pacific Energy Website

I have a P.E. Medium Wood burning fireplace insert. I want to hook it up to outside air. Does Pacific Energy make a outside air kit? Thanks,
^^^^^^^^^^^^^^^^^^^^^^^^

Hello,

For our inserts you do not connect outside air directly to the unit.
Below is the instructions from the manual regarding combustion air.

Combustion Air
Consult local building codes regarding combustion air supply.
Intake or combustion air can be supplied to the Insert
in one of two ways:
1) Outside air supply: Remove cover from ash clean out in
existing fireplace. Place a rodent screen in place of the
cover. Install the Insert as described in the installation
section, making sure not to cover the opening of the
air inlet. When installation is complete, seal surround
to fireplace and anywhere else air may enter. This will
ensure combustion air is drawn from outside the house
and into the 9" x 2" intake at the lower rear of the appliance

Regards

 

[fossil]

Sounds right...just as Tom said (who, unlike me, actually knows what he's talking about). I was stuck on thinking about a freestander rather than an insert. In the case of insert, with the front surround in place, the old fireplace serves as the air plenum. If your fireplace doesn't have an ash door (some don't), then I guess you have make a hole, then put some sort of screen in it and maybe a rain shield...like a dryer vent penetration without the damper built in. I apologize if I steered you in the wrong direction with my not-completely-thought-through, but nonetheless well-meaning comments. Rick

 

[fossil]

I can’t imagine an OAK installation actually increasing the pressure in the house, under any circumstances short of something like sticking a leaf blower right into the duct outside.

Heated air expands, so a woodstove that isn't dragging outside air into the house for combustion causes positive pressurization.

I gotcha, Tom. Makes sense, so long as the OAK is tight to the stove, and the house is real tight, then the heated air inside the house wants to expand. Thanks, Rick

Thinking about this some more. Can't imagine a house so tight that heating the air inside would actually pressurize the house to any measureable degree, unless you live in a submarine...which would be a pretty sketchy environment for a woodstove. Houses generally have at least one exhaust fan in a bathroom somewhere, maybe another in the kitchen, and the weatherstripping around doors & windows and other penetrations is never perfect. With an OAK installed, and a nice tight house, heating the air inside will certainly discourage cold air infiltration, but I don't think it's actually going to pressurize the house...at least not so's your ears pop. Talkin' maybe a couple millimeters of water delta P. The pressure will equalize with outside ambient one way or another. ;-P Rick