Make up air

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2wheels

Member
Mar 2, 2015
47
Ontario
I have been reading about make up air and I get the feeling it is a very contentious issue.
It is very difficult to do properly so it is avoided.

What if i just run a 4 inch pipe from outside into the basement and open the pipe near the floor?

That would dump cold air onto the floor continuously so what if I add a U joint near the floor and run the pipe back up the wall so it opens a foot from the basement ceiling? (kind of like a cold air trap)

I am just looking for comments, thanks.
 
I have use outside air for my Equinox and am very happy with it. The reason an OAK is contentious has many causes:

1. Is it really needed? The test for this is whether the stove has draft problems unless a nearby window is opened a bit.
2. The outside location is important because you can actually create more negative pressure if the outside opening is located on a wall of the house that has negative pressure with prevailing winds
3. Long runs are to be avoided but some people on this forum have very long runs that work well
4. The outside terminus of the OAK is supposed to be at the same level as the appliance and not above it (by code) but once again, there are people running an OAK down to a basement stove that is successful

There a great Cdn. gov't information booklet that has some info on OAKs. The link is here: http://publications.gc.ca/collections/collection_2009/schl-cmhc/NH15-436-2008E.pdf Since my OAK works fine, you can expect that I disagree with the info but it is a good general guide.

The relevant info is this:
It has been widely believed that smoke spillage could be reduced or eliminated by supplying outdoor combustion air through a duct, either directly to the appliance firebox or indirectly to the room in which the appliance is installed. However, research shows that outdoor air supplies do not work. When an exhaust fan is running, smoke spillage from an appliance can occur at the same pressure level, whether or not an outdoor air supply is installed. The same research shows that wind effects around the house can reverse the flow in these ducts, drawing air and possibly smoke through the duct to outdoors. This reverse flow can be hazardous if the duct is directly connected to the appliance firebox.A Guide to Residential Wood Heating 48 Canada Mortgage and Housing Corporation Some building codes still require that outdoor air be supplied to woodburning fireplaces. You must comply with this rule, but be aware that performance will not improve, and take steps to protect combustible materials around the duct from overheating if the gas flow reverses.

I think your idea is wrong to dump cold air and I don't think a cold air trap will work but maybe I don't understand (or misunderstand) your idea. However, there is nothing wrong in trying it, provided you don't create a reverse flue effect. Probably the great success of my OAK is just plain luck but it's 2' long and terminates on a south wall that should rarely have negative pressure due to house location and a bermed north wall. Of course, I get great draft with or without an OAK and that helps too even though my house was designed to be air tight. I actually have more of an overdraft problem with the OAK in place.
 
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I think your idea is wrong to dump cold air and I don't think a cold air trap will work but maybe I don't understand (or misunderstand) your idea.
Thanks
I am pretty sure my idea will NOT work. If it was that simple everyone would do it. I just had to ask as it is in my nature to do so. Also hoping to get excellent responses like yours.
I will read about OAK as I have not heard of this.
 
I will read about OAK as I have not heard of this
an oak is simply an outside air kit many stoves have an allowance to supply outside air directly to the stove through a kit. In some cases they are nessecary but many times they are not and will offer little if any gain. And like said previously if the intake is located improperly it can cause the problem to be worse
 
proper way through sill- down wall into a box terminating couple inches from bottom of box - next pipe from top of or slightly below up wall to however you need to connect to appliance . only reason to do it this way is to allow air to warm a bit before entering appliance also eliminates condensation problems or in my area snow sometimes gets sucked into the pipe gives it somewhere to melt to as well ( thats besides my double "U" outside) Not a fan of just a pipe open close by. A 4" open pipe can dump a lot of cold air
 
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