QUESTION ABOUT AN OAK

[leoibb]

just wandering if i install a oak what difference in heat will there be? what air does the stove remove from the room without one? is it worth the effort ?
people who have them whats your opinions? i live in a standard house no drawing problems stove works fine, i just wander what the difference would be with using an oak? my thoughts are without a oak then the heat keeps getting stole by the stove which then the stove has to re heate and keeps stealing it but how much is the question i guess

 

[ScotO]

The OAK takes outside air (air from outside your home) to burn the fire in the stove. Without the OAK, you are using heated INDOOR air to burn that fire, which in turn brings in drafts from the outside through any place it can get it (your house will be under negative pressure with the stove going, it's going to look for air from outside to balance out). The OAK helps eliminate drafts caused by your firebox. However, if you are poorly insulated in the ceiling and walls, that will cause a draft as well....

 

[leoibb]

yes i get that part but i think the main question is would the house be considerably warmer if i used a oak? i did read somewhere that the stoves uses on average the air in your home every hour which sounds a lot but if correct then i assume using a oak would make a large difference?

 

[ScotO]

yes i get that part but i think the main question is would the house be considerably warmer if i used a oak? i did read somewhere that the stoves uses on average the air in your home every hour which sounds a lot but if correct then i assume using a oak would make a large difference?

I think they are well worth the effort to install. Again, this also hinges on how well insulated your home is. If you are losing a lot of heat through your walls and ceilings, you may not notice a big gain in heat....

 

[leoibb]

thanks for that , its reasonably insulated , iv had a stove without the oak for a few years now and the article about the stove taking the heated air all the time got me thinking that's the only reason i think i will install one

 

[ScotO]

thanks for that , its reasonably insulated , iv had a stove without the oak for a few years now and the article about the stove taking the heated air all the time got me thinking that's the only reason i think i will install one

i think you'll notice a difference, especially on a really cold day. One way to test this is to go to your receptacles that are mounted on your outside walls, and feel if a draft is coming it (chances are it will be, especially in older homes that do NOT have sprayed foam insulation). After the OAK install, that draft should be decreased......

 

[Backwoods Savage]

The only down side to an OAK is sometimes during windy conditions you can get a huge draft blowing in but that is rare and the stove will be able to take it okay. When we had one we noticed a lot of difference with a couple different wind directions. We intended to put an OAK in with our last stove but never got it done but all is well.

Another thing is if the clothes drier is run a lot and/or exhaust fans, then and OAK really helps a lot.

 

[MnDave]

I just replaced a stove and added an OAK. The new stove is lighting easier and I do not have to worry about whether or not the dryer/water heater/furnace is running when I go to start. I use a torch to guarantee I have a good updraft before I light. I wait until I feel the first foot of stovepipe is warm. This is happening much sooner with the OAK.

If it is pretty easy to install I would definitely do it. Mine hooks right up to the bottom of the stove.

MnDave

 

[bag of hammers]

There's been a few OAK threads here but I don't recall if anyone talked about what happens with an OAK install when you're not burning (eg a weekend burner)? Will cold air move thru the OAK and into the stove and pipe and cause any issues like condensation? Not even sure that makes any sense but I suppose I'll be testing that notion sometime this winter when I get my OAK connected. Anyone ever see anything like this?

 

[Light in the Dark]

When I get my stove, I will make sure its a model that will accept an OAK. Past the fact that it will be pulling in colder, denser air... it also keeps that warm (and humidified!) air in your house. One of the biggest gripes Ive always heard about woodstoves is how dry they make a house feel... makes total sense when the stove is consuming all that moist air in your house!

 

[MnDave]

When I get my stove, I will make sure its a model that will accept an OAK. Past the fact that it will be pulling in colder, denser air... it also keeps that warm (and humidified!) air in your house. One of the biggest gripes Ive always heard about woodstoves is how dry they make a house feel... makes total sense when the stove is consuming all that moist air in your house!

+1 metalsped

I was just coming back here to make the same comment about humidity. I was just telling my wife that I was surprised that we were not getting shocks in the house. I have been getting them when I get out of my car.

Then I realized that the new stove with OAK is already making a difference.

 

[Machria]

The new stoves use such a small amount of air, I can't see it making that much a difference.

 

[westkywood]

I installed an OAK last year. I live in a house that was built in the 30's. I've got good attic insulation and new windows. Some of my walls have no studs so they obviously arent insulated, but last year I studded out a bedroom and insulated it and plan on doing more of that. My point is, even tho I added the OAK , it's hard to tell how much difference it made because of all the other things I'm doing to the house. To me it just makes sense to install an OAK. In an old house it cuts down on drafts. In a newer home it wont conflict with the dryer or bathroom vents.

 

[Curly]

I'm not sure exactly what an "OAK" is but I have an idea. Can't just slightly opening a window (what I'm doing) do the trick?

 

[ScotO]

The new stoves use such a small amount of air, I can't see it making that much a difference.

They use a lot more air than you think! If you have a fire going and a draw in the chimney, that stove is sucking air from somewhere. I'd rather it suck air from the outside of the house than the heated air from the inside of the house.

 

[westkywood]

I'm not sure exactly what an "OAK" is but I have an idea. Can't just slightly opening a window (what I'm doing) do the trick?

Outside Air Kit.. Not the same as opening a window. The air comes in to the stove from a hose ( aluminum dryer vent hose ) directly from outside. its a closed air system. Opening a window lets cold air into the house. With the OAK, the stove gets all of its air directly from outside rather than from inside your home....

 

[ScotO]

I'm not sure exactly what an "OAK" is but I have an idea. Can't just slightly opening a window (what I'm doing) do the trick?

that will work, but your using the heated air of your house to fire the stove. The OAK takes that cold, outside air and pulls it directly into the stove (rather than dragging it through your house)

 

[leoibb]

thankyou all for the comments , it certainly makes sence to me too

 

[John_M]

leoibb, here is a link which provides good information about the benefits of an OAK: (broken link removed to http://www.chimneysweeponline.com/hooa.htm)

My home was built in 2004 and quite air tight. Rather than burn inside air I installed an Outside Air Kit (OAK) to funnel exterior air to my Spectrum. The 4" aluminum feeder tube for the OAK is centered under the stove's pedestal. It goes DOWN through the 11" elevated hearth, through the floor and extends through a back wall like this: (broken link removed to http://www.pacificenergy.net/pacificenergy/pdfs/SUPER-SD1-250112-20.pdf) Scroll down to page 7 to see why one picture is worth a thousand words.

To answer the question about cold air entering the house through the OAK when the stove is not firing, here is my opinion: Cold air does not RISE unless encouraged to do so by an outside influence. My EXPERIENCE has been that even during sub-zero outside temps, I can feel no air entering the house or stove through the OAK when the stove is not burning. However, the galvanized metal elbow (located in the full unheated basement) connecting the vertical pipe to the horizontal pipe through the back wall does develop some frost covering at sub-freezing temps but that frost stops about 9" up the vertical pipe.

It should be mentioned there is a double hung window almost directly behind my stove. I keep the top half of that window open about 1/4" through most of the winter. I have the IMPRESSION that inside air seems fresher with that winow open just a teensy bit.

During summer months I stuff fiberglass insulation into the dryer hood feeding the OAK so bees and other undesireables cannot enter the OAK system. This requires that I open a cover behind the stove's pedestal so I can burn wood during those occasional cold and blustery days we experience here in central NY...the same ones you probably experience in the UK.

Good luck and best wishes.

 

[El Finko]

Any opinions, folks, on how long an OAK can be? I have a 30 NC in the basement so it'd be about a 9-10' run up the wall to get the OAK up to the rim joist and outside air. I have toyed with the notion of stepping up the diameter of the hose from 3" to 6" or something larger about halfway up the basement wall.
I did ask the tech at Englander and he said the kit is not designed to stretch that far (obviously), but he was dubious about effectiveness of increasing diameter of the hose.

 

[DickRussell]

One problem with not having the OAK is that when the fire burns out overnight, the path from the room up through the chimney remains open, and interior continues to flow up the pipe the rest of the night. That air gets replaced with cold outside air leaking in. With an OAK, the air still flows slowly up the pipe, but it's a closed loop, and the replacement air comes directly from outside, into the stove, and up the pipe, without mixing with interior air.

Not all stoves provide direct attachment of an OAK duct. With some, you just dump the air from the duct into the vicinity of the stove. When I was looking for my stove, I was looking at a small Jotul and a small Quadrafire. The Jotul had no direct attachment of air duct, but the Quad did, so I got the Quad. I also installed a damper in the stove pipe, up just below the ceiling, which allows me to close off the air loop when the stove is not in use. Those dampers don't completely shut off the flow, but have openings in the flapper to permit some minimal flow (mine had openings in the form of the letters "ICC"). I had a welder weld some light plate over those openings. I just have to remember to open that damper before lighting the stove. Since the house is supertight, I also have to remember not to leave the firebox door open after lighting the stove if the clothes dryer or range hood is on. Don't ask me how I learned to remember these things!

 

[bag of hammers]

However, the galvanized metal elbow (located in the full unheated basement) connecting the vertical pipe to the horizontal pipe through the back wall does develop some frost covering at sub-freezing temps but that frost stops about 9" up the vertical pipe.

John thanks for the info on your experiences. My 2 concerns are (1) cold air flow when the stove isn't in use and (2) the frost situation as you mentioned. I'm thinking that (1) is a non-issue, if as you noted the air will not normally flow up the pipe unless there's a fire / draft, and (2) I might just add an insulation sleeve over the metal OAK pipe so it's not acting like a big "condenser". I'm sold on the idea, worst case I think would be it won't do much, best case is I get all the benefits described here (and in other threads).

 

[John_M]

leoibb and bag of hammers, an insulation sleeve over the exposed galvanized 4" pipe closest to the exterior wall is an excellent idea. This is where the coldest air (sometimes as cold as -20 ) enters the OAK system. My basement stays approx. 50during the winter months. When large volumes of frigid outside air enter this pipe, "warm" basement moisture condenses on the freezing pipe and presents a frost coating..

I have been meaning to wrap the elbow area with fiberglass insulation but because the frost does not create a problem and because the elbow is in the basement, it is out of sight. And in my case, "Out of sight" does mean "Out of mind". Perhaps I'll get to wrapping the elbow this week.

Best wishes and good luck.

 

[ScotO]

Any opinions, folks, on how long an OAK can be? I have a 30 NC in the basement so it'd be about a 9-10' run up the wall to get the OAK up to the rim joist and outside air. I have toyed with the notion of stepping up the diameter of the hose from 3" to 6" or something larger about halfway up the basement wall.
I did ask the tech at Englander and he said the kit is not designed to stretch that far (obviously), but he was dubious about effectiveness of increasing diameter of the hose.

I think Napoleon recommends an OAK no longer than 20ft in the NZ3000 manual, not sure if this is an industry standard or if it pertains only to the NZ3000. Mine is around 9' long total, going through two 90 degree elbows along the way. I also put a "trap" in the flexible pipe to keep any backpuffing from happening. I noticed when I first installed the OAK I was having condensation issues INSIDE the pipe closest to the place where it came through the exterior wall, so I wrapped in in foil-backed fiberglass insulation and I haven't noticed any more condensation since.

 

[bag of hammers]

"Out of sight" does mean "Out of mind"

Similar situation here - I have an unheated crawl - it's well insulated though and it stays @ 50 deg in winter. I won't see the OAK but knowing there's any moisture or condensation happening there would drive me nuts. Thanks for the info and the sanity checks.

I think Napoleon recommends an OAK no longer than 20ft in the NZ3000 manual, not sure if this is an industry standard or if it pertains only to the NZ3000. Mine is around 9' long total, going through two 90 degree elbows along the way. I also put a "trap" in the flexible pipe to keep any backpuffing from happening. I noticed when I first installed the OAK I was having condensation issues INSIDE the pipe closest to the place where it came through the exterior wall, so I wrapped in in foil-backed fiberglass insulation and I haven't noticed any more condensation since.

I don't recall reading anything about length of OAK from SBI, but their OAK kit (adapter / flange and vent hood) is 5" diameter - they specify 5" flex pipe, which I think is a lot of pipe for fresh air. My run will be approx 15' - a few inches down from under the hearth / pedestal, a 90 deg bend, then straight across horizontal and out the wall. Scott how much insulation did you need to use around the pipe - inch or 2 thick? or more? Also interested in the "trap" you mentioned - maybe something to add here too since I'm in the process now...?