Outside air

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
Status
Not open for further replies.
Like I mentioned in an earlier post, not having OAK is just like putting a fan in your window blowing out. Nobody in their right mind would do that so why would you allow your stove to draw in your already heated house air then blow it outside?
 
Pascal - Great info, but I have a few questions regarding your response. The fresh air kit you've mentioned is meant to combat the exact issue I have mentioned in a few different threads...its backfills the basement with outside air to equalize pressure created by the stack effect of homes built from 50's-early200's. For those that have finished lower level (basement) rooms with the stove installed there, pressure issues would be amplified by running a stove with no OAK especially with a flame fired water heater or furnace. In extreme cases this can result in the chimney losing flow, and is often indicated by homes suffering from 'cold hearth' syndrome as well...or negative pressure stoves that fill with smoke if power is lost. At the very least, for a stove installed in a lower level (low pressure/vaccum zone) the combustion blower has to work harder to draw the appropriate level of air in the stove. Installing the OAK allows the stove combustion area to run at a 0 pressure differential intake to exhaust that is then controlled 'optimally' by the exhaust combustion blower without fighting with pressure variances from inside the house to the outside air.

Also...probably not to the degree of adjustment you're mentioning, the Enviro M55 does have trim adjustment for the combustion blower. Most of the older stoves I've seen have a manual convection (room) blower, but in most cases I assume you'd want the room blower running no less than the heat level recommended setting to avoid over heating/stress issues in the stove metals?
 
I'm not running an OAK at present and the stove burns fine as far as I can see. The wood stoves that I burned in the exact same location in the house for almost four decades burned fine also. I'm not opposed to adding an OAK, I'll ad one when I'm convinced I need one.
 
My Harman Advance-2 is installed in the basement using an existing chimney. I have been using it for years without an OAK. How would I connect the outside air to something that is below grade? Any suggestions? Here is pic of my setup (disregard the surge suppressor, my Isobar was in my shop somewhere. This was just a test run...)
 

Attachments

  • Copy.jpg
    Copy.jpg
    83.7 KB · Views: 254
Last edited:
Rick - Mine is run up the chimney flue with my exhaust duct, which is obviously not an option for you. If you are not having any issues with heat rising or maintaining a good flame/draft I don't think I would worry about it unless someone has a good and easy solution on here.
 
I'm not running an OAK at present and the stove burns fine as far as I can see. The wood stoves that I burned in the exact same location in the house for almost four decades burned fine also. I'm not opposed to adding an OAK, I'll ad one when I'm convinced I need one.

Unless you live in a mobile home or your house is VERY well, OAK is seldom needed but it will improve your stove's performance and reduce drafts in your house.
 
I'm not running an OAK at present and the stove burns fine as far as I can see. The wood stoves that I burned in the exact same location in the house for almost four decades burned fine also. I'm not opposed to adding an OAK, I'll ad one when I'm convinced I need one.
I don't think anyone is saying your stove won't burn okay without an OAK (maybe that long-winded post - I gave up trying to read it), just that in a lot of cases and OAK will eliminate/reduce drafts felt from outside air infiltrating the house envelope as the combustion motor is drawing air. If you don't have that issue (and some don't), then there is no reason for you to change what you are doing presently.
 
I'm not running an OAK at present and the stove burns fine as far as I can see. The wood stoves that I burned in the exact same location in the house for almost four decades burned fine also. I'm not opposed to adding an OAK, I'll ad one when I'm convinced I need one.

My attempt to 'convince' you an OAK is worth it.

An OAK isn't so much about the quality of burn as it is about efficiently heating your home. I think we can both agree that during the winter, we want to keep the heat in and the cold out. Without an OAK, the opposite more easily occurs. You are REQUIRING that cold air be pulled in through every possible point in your home that is not air tight. This is because your stove is using the already previously warmed air in the house for the combustion process and sending some of it out the exhaust. This air HAS to be replaced and IS replaced by cold air from outside and cooler areas of the home (draftiness).

A non-OAK home has an inside air pressure that is lower than the air pressure outside of the home, so cold air is drawn in through the walls, windows, doors, etc. This is the main reason, at least that I know of, why mobile homes are required to have OAKs.

With an OAK, you use cold air for the combustion process, creating a home that has a greater air pressure inside than outside. The already previously heated air stays in the home much more efficiently, you feel warmer and, I would wager, use less fuel to achieve the same comfort level.

Basically, do you want to draw cold air in or force warm air out of the home?

Example: I just replaced the wood stove (non-OAK) in my mother's house with a P43 w/OAK. My mother has already noticed the absence of cool air flowing at floor level around the room where the stove is. The room heats up quicker and stays warmer much easier (less fuel needed).
 
  • Like
Reactions: David M
I have a brick ranch home with attached garage and was debating running a oak to my stove from the garage instead of another hole in the brick plenty of outside air gets through the garage doors but it wouldnt be as cold as directly from outside
In most places it is not legal to pull air from a garage into a stove's combustion chamber. The risk is that combustible gasoline fumes from the garage can cause an explosion when ignited by the stove.
 
In most places it is not legal to pull air from a garage into a stove's combustion chamber. The risk is that combustible gasoline fumes from the garage can cause an explosion when ignited by the stove.
well here in quebec its mostly that they dont want carbon monoxide to be mix with the air in the house, if the garage is prouve to be
condemned then you will be alouded same rule just for hot air ducking.
 
Pascal your language conversion is about ready to have me rolling on the floor. Hot air ducking? That's what I had for Christmas, Indian runners:) Local TV station was giving the weather for this weekend and they even printed it "Dear hunting opener" Three people didn't catch it
 
Last edited:
  • Like
Reactions: bogieb
Pascal your language conversion is about ready to have me rolling on the floor. Hot air ducking? That's what I had for Christmas, Indian runners:) Local TV station was giving the weather for this weekend and they even printed it "Dear hunting opener" Three people didn't catch it
dear vs deer Daaah! ok ok I was at lunch an did not doble check my spelling, lol.... remember that Im french and doing my very best to be understandable but I also find this very funny.... what are Indian runners!? I which I'd go for dears hunting but my wife wont let me lol.
 
  • Like
Reactions: bogieb
Indian runners are a duck close in size to a Mallard but run - walk almost upright. Not as fatty as Moskovy. I remember the fact your principle language is French. Interesting how some things get translated and recognized by computer too
 
  • Like
Reactions: bogieb
Sacrebleu!

Our Muscovy ducks are not Fat!:eek:

Must be our organic feed. Once processed and canned, they taste like and are a healthy replacement for the beef in beef stews we make.:cool:
 
  • Like
Reactions: bogieb
Goose and duck fat is some of the best lard replacement for making sugar cookies. Gaining weight just thinking about holiday cooking.
After we carve most of the meat off what ever bird we have for dinner the rest usually goes to the soup pot.
 
  • Like
Reactions: bogieb and Ambient
Purchasing my first pellet stove. Have received conflicting advice on whether to arrange outside air intake for combustion vs allowing the stove to draw room air into combustion chamber. How important would this be in a typical residential installation? (Stoves considering are Harman XXV and Quadrafire Mt. Vernon AE)
Thank you.
My recent OA install. Got the flex tubing from HD in the house vacuum dept..then it transitions to PVC at the wall. ea7503fa5a7be3a0ea16f48af5dd5ef9.jpgfe44185453b06b4deedb0dd92bf0ee17.jpg
 
Is that flex hose plastic?
 
Kind of a heavy duty vinyl with metal rib...
The OAK should always be of a fireproof material. In the event of a burn back the PVC can be damaged by the heat and emit knoxious gases.
 
  • Like
Reactions: Wilbur Feral
And we're off to another pellet season. I can always tell, 'cause the OAK debate starts. Do whatever you want, folks. Or, learn physics (and install an OAK).

BTW, we should start a pool on number of times topic comes up between now and April.
 
Thank you everyone for your thoughts and advice. I appreciate it.
- robert

And this thread cleared up a lot of my questions. I was mystified as to why all of the stove stores and installers recommended against the installation of an OAK.

Many thanks to all also.

Building Permit arrived by mail today (trying to do all things legal, keep the insurance demons happy). Hope to get everything in place over the weekend. Just in time for the cold to come back in the area.
 
  • Like
Reactions: bogieb
Status
Not open for further replies.