I have had multiple conversations with Woodstock (great people by the way) stove and have settled on the final floorpan for our house to be built. In the floorpan I have the stove placed near the middle of the open floorpan allowing me to run a straight shot or at most one 90 on the exit pipe for about 16-17 feet of total length. I have it near the center of the home and thus the highest point of my roof which will keep as much pipe as possible inside conditioned/tempered air to help the draft some more. I live at 4400 feet in CO and in a high wind area so between the guidance of woodstock who said go at least 15 and sensibility to the wind I feel that is as good as it can possibly be. The part that has me wondering is even though I explained to them that the home will be built by me so care and attention to detail for insulation and sealing will be on the higher end I was strongly advised not to use or at least not initially install a outside air kit. Essentially saying that the high efficiency Paladian that we picked will not like starting on those cold days and would much prefer pulling in tempered air from the house; and that most houses even "tight" ones still have enough leakage to allow for that. He did mention one caveat to that is to make sure that there are not a lot of competing gas appliances as that could cause a bad situation. I will have a direct vent insta hot, an electric range and the only things competing for air will be the range hood when on and the propane dryer. So how many of you have actually needed an OAK for your stove or how many of you installed one from the get go and did not have any problems with startup and combustion air temp issues. I am trying to give every consideration in the design aspect of the house and stove to avoid frustration, extra cost and inefficient operation.
How many of you are using or "Need" an outdoor air kit
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No OAK here. No problems without it. No experience with one.
Thought this was an interesting article. http://www.woodheat.org/outdoor-air-supplies.html
Thought this was an interesting article. http://www.woodheat.org/outdoor-air-supplies.html
Dang....now this is why I come here! Not only would it be a bad idea in general but in my case of high winds it is an even worse idea. I will go with what Woodstock advised as well as what the studies are pointing to and omit the OAK.
TimfromMA
Minister of Fire
I also live in CO, at 9100 ft. and have done many installs at altitude. I'd generally agree with Woodstock that pulling room temp air is preferred to outside air, especially when said outside air is 10 degrees and blowing 60 mph! If your flue is exiting near the peak of the roof and there is minimal competition for make up air, it shouldn't be a problem. An OAK on the windward side of the house causes more problems than it's worth, IMHO.
Tenn Dave
Minister of Fire
I have one of the first early model Progress Hybrids that had a slight smoke smell problem. My house is newer construction and has a slight negative pressure. I tried the OAK and it did little to solve the smoke problem. Woodstock looked into the problem, solved it, and issued repair kits at no cost to all of us in need. I disconnected the OAK and the PH has been working perfectly with absolutely no smoke smell. If I were you I would go with what Woodstock and the other posters are saying and not use the OAK. And I would like to mention that Woodstock will be just as helpful to you post purchase. They are great people to work with.
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It makes sense to me that in my situation an OAK may be beneficial but yours not so much. I have a poorly insulated block home built in the 1950s. Leaky windows and the most remote bedroom (which happens to be mine) gets very cold. With the stove drawing combustion air from inside the home that is going to suck on all the leaks right? I'm wondering if an OAK is not the right choice for me.
Oh and yes I do plan on replacing windows and better preparing my home for winters...but this is a not new construction either!
Oldman47
Minister of Fire
Let me tell you my thinking on this subject. I am also in the process of building a new air tight home. In my case the nearest wall to provide outside air is over 10 feet away. The only exhaust in the whole place is the dryer vent. Darned near no other penetrations exist in the outside wall so I expect to be fairly air tight. When I looked at my stove I saw that an OAK could only be connected to the back or to the bottom. I have no idea whether or not I need an OAK so it came down to practicality. If I ignore the need for an OAK I may win or I may lose. If I lose and need to add an OAK it would mean moving the stove out of the way to cut holes in my hearth area and then running the OAK pipe up from the bottom, then moving the stove back in place to connect it.On the other hand I did run that OAK piping in my basement and set it up to connect to my stove. With the stove in place I will be connecting the OAK piping to the stove. Where does that leave me? I will draw combustion air from my unheated basement and if I really need an OAK I can just cut through the exterior wall to tie my OAK outside. I love it when I have options to deal with the real world.
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certainly your unheated basement has ventilation to the outside of some sort. Sounds like your OAK from that area will be sucking in the cold air which will chill your air temp down there!
Oldman47
Minister of Fire
No the basement has no intentional vent to the outside. It is possible that it might leak the same way that my main floor walls might leak. It is the place that the hose connections go through the wall but I filled those holes and the holes for the power connections with gaps and cracks Great stuff. Those spots are sealed at least as well as places where the rim joist is a solid piece of wood. I built this house as tight as I could and tried not to miss a trick. I will not be surprised if I need to use that OAK.
The way i see it if you have a very tight house you will probably need an oak. Also if you hous is pretty leaky and your stove is on a low level you can get negative pressure from the chimney effect. But honestly in most cases that i have seen and most stoves i have installed there has been no need for one. And typo if your house is really as leaky as you say i seriously doubt that the stove pulling air out of the house will make any difference on the amount of drafts you have They just dont use that much air an open fireplace on the other hand could do that possibly but even then i doubt it would make a noticeable or measurable difference
iluvjazznjava
Member
For me, I had no choice. I got on OAK installed with my Jotul stove install as building code in my area requires it now. My dealer said there are some people that just get one put in to pass inspection and then disconnect, but he said to try it with it hooked up and see what performance I get. My stove works great with my OAK. I understand that you need to be careful where you put your OAK intake outside or you could have issues. One of the big advantages of the OAK is that my stove doesn't suck humidity out of my house any more. When you use outside air for combustion, you don't dry out the air in your house. If you have a way of humidifying the house, or if you want lower humidity, then stay away from the OAK. If you want to maintain humidity, consider the OAK for that reason at least.
I was prepared to put one on my new stove as my insert has one but when the stove got it's WETT inspection the inspector told me don't bother hooking it up, his opinion was that it would work great without it. Mine is a straight shot up no bends thru a vaulted ceiling and total height to cap is close to 20feet. It works really good and I haven't hooked up the OAK. My house is reasonably air tight. I did notice my insert which I had to run temporarily without the OAK hooked up while renovations were going on did not work very well. I commented on this to the inspector and he said the design on the insert is such that it won't work well without an OAK.
The only time I have any problems at all with the new stove is when I'm starting from a dead cold stove but I found using the hairdryer on the primary air intake port is the perfect way to ensure that no smoke comes in the house when I'm starting the stove up.
E.
The only time I have any problems at all with the new stove is when I'm starting from a dead cold stove but I found using the hairdryer on the primary air intake port is the perfect way to ensure that no smoke comes in the house when I'm starting the stove up.
E.
The flue design really has absolutely no impact on whether or not you need an oak. The determining factor is whether or not you have enough makeup air to supply the fire with combustion air. I dont know where your inspector got that idea but it is not true.
Bagelboy
Feeling the Heat
I have two stoves, an airtight home(R19 walls and R38 attic), and heat strictly with wood. I have never needed an oak, and even if I did, I think I could crack a window just to get some outside air in to help, but have never need to. If you're concerned, I'm sure getting one installed is nominal, but I would be surprised if you need it.
An oak is a much better way to do it for sure opening a window just lets air into the house an oak puts air into the stove
How come in our area any home built with gas heat requires an oak for hot water tank and furnace? Have you ever put your hand on top of a chimney thats hot and felt how much wind is coming out? I cannot imagine loosing that much heated and humid air leaving my home. OAK for me 35 years
When you look at the air exchange rate in most stoves that air leaving the chimney is just a drop in the bucket. I am by no means against oaks but in most cases they are not needed but even if they are not needed If they are installed correctly there isnt much of a downside. And your example of gas appliances is a totally different situation
If you can plumb into your crawlspace below your stove, it sounds like you would be pulling air from the approximate center of your house. A very slightly leaky crawlspace will normalize to the similar pressure as a home--especially at the center of the crawlspace. In addition, you will be pulling half heated air into your stove. On very cold starts, my outside air chills the stove intake and it takes longer to get a good flame. I may switch the intake to draw from the floor of the crawlspace and just ensure enough air leakage into the the crawlspace.
Homes in my area have only had make up air for gas appliances 17 years or so . homes got tighter so oak. I can put a papertowel on my oak inlet and I have to peel it off. I would like to Know from a person in the know how much cubic feet of air my 8 in chimney shoots out a 25 degree day. I sure dont know
Gas appliances have increased their efficency allot in the past 17 years which demands a more consistent air supply and necessitates fresh air intakes. And no not all homes got tighter i agree on new construction i would say that an oak is a good idea but many of us do not have new or close to new construction. You would need to measure the volume of air escaping no way to estimate. But the average us home has an air exchange rate of 1.8 times per hour and the average is dropping. New construction can be much less than that typically .3 to .5 but many older homes are much higher. In new construction yes that stove exhaust is significant air loss but on average or below average homes it really is not significant
We built a very well insulated and air sealed home last year - closed cell foam everywhere, more caulking tubes and cans of spray foam for sealing details than I could count. Final blower door test was .28 ACH in a 1600 sq ft home - tight!. We have a Woodstock Keystone in the house and without an OAK, every time we turned on the bathroom fans (80 cfm) we extinguished the fire. Every time we used the fan over the stove (150-600 cfm), we'd suck the smoke out of the stove and straight into the house! Running the dryer produced similar issues. This was with a slightly positive interior pressure from the HRV. We got used to opening windows whenever operating those devices. Installing an OAK took care of those problems and has produced zero discernable difference in cold start-up. - and we live in a cold region. Your house may not be this tight, but I'd at least make the accommodations for the OAK with a hearth penetration, etc. if I were you.
It really will depend on just how tight your house is - the guys at Woodstock are probably not familiar with the contemporary notion of "tight."
It really will depend on just how tight your house is - the guys at Woodstock are probably not familiar with the contemporary notion of "tight."
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I think you really want the air entering. Escaping volume is misleadingly higher as it 1) is much hotter, and 2) also composed of burn gases CO2, H2O and others.
Air exchange figures can be misleading. An exchange measured by the standard blower door test of 1/hr doesn't mean your house will have 24 exchanges on a given average day. The figure is much less because the blower test depressurizes the house considerably! Looking around the web, the rule of thumb is to divide the ACH50 by 20 to get the natural air exchange rate.
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