length of fresh air intake problem

I don't have an oak on my insert but my guess is its a system, if the chimney is high with more draw I would not think it would make as much difference. If its a short chimney and little draft, well it probably would effect it more???

I'm running almost 20 feet of 4 inch insulated flex ducting. My fireplace has the option of using inside air and/or outside air at the same time. I haven't found any notable difference between the two.

I know on my furnace (different but similiar) there was a max published. I upsized the pvc and stayed within specs, and downsized right at the unit...works great!

17 feet would be no problem. You could always run smoothwall pipe instead and you could run larger diameter but I doubt either is required.

Yeah I can't see noticeable pipe losses happening in 10 feet of 3" rigid piping. Whatever you use for a rodent/insect screen on the intake face will be a much bigger factor in air supply losses. Same for bends - much more losses w/ a bend vs. a few extra feet of straight pipe. Go for it.

I'm planning an OAK possibly, and it will be about the same - 10 feet or so...

Have you consulted the manual to see if this is mentioned specifically?

For your stove a 3" diameter OAK would suffice.
Given your restriction of 10 feet length, and a bend, a 4" diameter should do just fine.

OAKs are not universal, and I have found out that all that is necessary to design and install a successful OAK is some common sense.

My OAK is only 3 feet long (passes trough the 1-foot thick wall of an external chimney) and for that I used flexible dryer duct on the inside, and two galvanized HVAC 45° elbows on the outside to direct the intake above snow-line and adjust for prevailing wind direction if needed.
In your case (basement, etc.) I would suggest PVC or ABS pipe to the point where it hits the floor of your room, then perhaps flex duct to the stove. Others may have more experience with setups passing through basements/crawl spaces.

Just my $0.02.

I have a 3" flexible duct approx. 6' long bumped it up to 4" pvc solid sewer pipe for the next 12' and Lowes had a drain that fit inside the pvc that made a good screen. I can tell no noticeable difference on the way it burns with the oak hooked up or not. Stove is an Englander 13 nc.

The manual says you need a 4" duct for the optional outside air - did you read it??. That length does not appear to be a problem as far some other stove manufacturers recommend. I would run some 6" pvc for the bulk of the length to be sure and then drop down to 4" pipe appropriate for install.

It doesn't give recommended length but here are some instructions:

http://www.chimneysweeponline.com/cpacaldert5.htm

From what I seem to recall, OAKs on other stoves are typically 3" in diameter. All the PE stoves use a 4" diameter OAK hookup. So, I like to think it is over sized already.

I used aluminum dryer duct for my stove. But, if you have a longer run, something else may be more appropriate and cheaper. I like the fact that I didn't have to purchase a "kit" to hook up to my stove.

wood is 1/2 air & OAKs are controversial. i have adversarial link listed below from WOODHEAT.ORG which u might want to read.

Click to expand...

That is an interesting link!

I agree with Nic36. Use metal dryer vent, my OAK is a dryer vent on the outside of the house with the flap removed and it is piped to the stove using 4" dryer vent pipe. I have read that others on this board have had OAK's travel well over 10 feet vertical, so I can't see that your's would be a problem.

I recently disconnected the outdoor air kit to my VC Defiant NC Everburn. The stove ran ok for these touchy VC NC's before the OAK, but I wanted to see if adding one made a difference in terms of stove performance as well as heat in the house. I used 4" dryer vent on an 18' run on a mostly straight shot and tried it for a month. I was disappointed as there was no noticeable difference in house warmth for similar outside temps. However, the stove became MORE touchy, less predictable, and less controllable with the OAK installed and would often backpuff due to build up of gasses and probably not getting enough air to the combustion chamber. I concluded that while there may be less air infiltration via windows etc. into the house with an OAK, the air quality was worse because of the frequent backpuffing and lack of fresh air exchange to get the smoke out, so I took the OAK off and have been happier. Note that my house is FAR from tight. bob

The outside air kit I installed was for a pellet stove which had a 2 inch diameter fresh outside air intake colar.

To this I put on a 3 ft section of air cleaner intake hose & clamped it tight with a automotive radiator hose clamp,

I used The hose that goes from the bottom of the air cleaner horn to the sheet metal over the exhaust manifold on a 350 chevy engine. I bought the hose from auto zone. It is 2 inch diameter , corrigated, flexable & accordian expandable & fireproof.

I only needed the single 3 foot length but the instructions for the pellet stove said that if I went longer than 3 feet I would need to transition to a 4 inch diameter plastic pipe to reduce the intake air drag.

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The instalation instructions wanted me to double the diameter of the cold air intake pipe for runs over 3 feet. From a 2 inch dia at the pellet stove to a 4 inch dia in the basement.


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The section that clamps to the stove may need to be heat proof but any section more than 3 feet away does not need to be heat proof.

You will be better off if you transition to a larger diameter smooth walled plastic pipe as soon as you get into the basement
to make up for air drag through the pipe.

See what you can find in the way of 6 inch or even 8 inch diameter pipe at lowes or home depot.

4 inch diameter pipe may be ok but if it is not, you will wish that you put in 8 inch dia to start with, because you will have to do the job twice to get it right & have to pay for twice the materials.

Especially with the 90 degree bend that you say you will have.

A smooth walled pipe will give better air flow than a accordian flex pipe because the walls of the pipe are smooth & not accordian ridged.


My wood stove, ---in the basement---- does not have a OAK fitting colar, so I am stuck with using room air, but the uninsulated house leaks air like a screen door anyways, so for me it dont matter.

The pellet stove in the living room got a OAK from day 1, so I dont have any prior
opperation to compair it to.

Good luck with your choice & let us know how it works out 4 U.