Fresh air intake

How many people run a fresh air intake on a wood stove. I currently dont run one and I was wondering if my heating be moe efficient if I did. It seams to me that all that air going up the chimeny must be drawing cold air in the house from somewhere.....

I disagree with Tree co

TreeCo said:

No outside air intake is needed. Houses have enough air exchange to provide the amount of air needed for an indoor wood stove.

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Not all houses are drafty.Evaluate your windows and doors.

ericjeeper said:

Not all houses are drafty.Evaluate your windows and doors.

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agreed, however in modern houses its kinda troublesome to get fresh air intake beneath the floor like in old style houses which had different kind of floor system compared to modern concrete slab style...

My house is one of those rare exceptions, but it is because I have a dual flue chimney. If the house is closed up tight and I run the clothes drier or an exhaust fan sometimes the smoke will go up one flue and back down the other. Just gotta open a window when the drier is running. Other than then - no fresh air needed.

I don't see how it could hurt, in my case it isn't needed. On the other hand, my friend has a large, new house and the builder built in a 4" cold air intake from the outside to feed his 2 furnaces and hot water heaters. He did add a flapper to shut should there be a fire so it doesn't feed it.

TreeCo said:

No outside air intake is needed. Houses have enough air exchange to provide the amount of air needed for an indoor wood stove.

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Sorry to disagree with you. yes most house do have enough air for combustion, but some of the new tight houses dont. mine will draw a negitive without an outside combustion source.

H

If it is not too much trouble to install, what have you got to lose?

This is also true for Oil and Gas Burners. Some of these new super tight houses need Fresh Air Intakes on the Oil Burners as well. My brothers house isn't tight, but the washer and dryer are located in the same room as the oil burner. If the dryer is running, he gets a bad burn on the furnace so we had to install a Fresh Air Intake kit on it. AKA Air Boot

Here is a link: Air Boot

If you install one of these yourselves, remember that the mixture needs to be adjusted as you are changing the air intake ratio.

Does a lack of fresh air intake cause already heated air to be used for combustion? In other words...drawing the air you're paying for to heat and want to keep in the house? Would having a fresh air intake reduce the amount of heated air loss? I'm asking this more for my oil boiler, not my wood insert.

hanko said:

Sorry to disagree with you. yes most house do have enough air for combustion, but some of the new tight houses dont. mine will draw a negitive without an outside combustion source.

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+1 ! I have the same problem : house is too tight because of use of PVC windows (in combination with brick walls).

- in normal conditions, I feel the air in our living room is getting 'poor' after a few hours of burning, it's not confortable.
- if my wife is cooking with the fan "on", I have immediately negative pressure in the house, and the fire will go bad (smoke will enter da house if you open the stove door)

We always have to open a window a little to let fresh air come in. I wish I had left an opening behind the stove into the basement, so that it could take fresh air from there. I still might do that in the future, but it's a built in stove which involves quite some work.

curdy said:

Does a lack of fresh air intake cause already heated air to be used for combustion? In other words...drawing the air you're paying for to heat and want to keep in the house? Would having a fresh air intake reduce the amount of heated air loss? I'm asking this more for my oil boiler, not my wood insert.

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that's a good question. One would have to calculate the volume of air needed for combustion and a calorific comparison, but it's almost 20 years ago since I did that...:help: :help:

My stomach tells me however that in either case, you ARE drawing fresh air in (direct or indirect). The heat loss would therefore be almost the same, as there is a to small difference between air intake temp and room temp compared to chimney temp.

TreeCo said:

Installs that don't work well without outside air input likely have other problems such as chimney height, poor chimney location or poor chimney design and construction.

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Very true, as this has an immediate impact on the "draft" capacity or negative pressure the chimney creates. I noticed a significant difference in our chimney capacity depending on wind direction and speed. But an additional fresh air intake does the trick for me.

I realize my suggestion for not needing an outdoor air supply is being 'beat down'(and I'm cool with it) but I will post this link again:
http://www.woodheat.org/outdoorair/outdoorair.htm

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i read the info at that link. it makes some very good points and before anyone does install some kind of fresh air source, they should read it.

TreeCo said:

Here is info about research on outdoor air supplies for indoor wood stoves. They are rarely if ever needed in even the tightest houses.
The problem with outdoor air supplies
It seemed like such a good idea until it was tested.
http://www.woodheat.org/outdoorair/outdoorair.htm

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thanks for the link, I read it all. Not sure if I agree, but now at least I'm a lot more informed.

For sure, what goes out ( the house ) must come in, that's undisputable. The question is... where is the best place to expend the energy to raise the air temp. Lower household object's temp to raise the temp of fresh outside air as it seeps in house cracks, or expend more log's btu's to maintain the temp of the stove's interior, offsetting the cold air induction. Pick your poison

TreeCo said:

On the other hand cold outside air entering a wood stove cools the fire box and can result in less efficient combustion inside the wood stove.

The result most times is a greater loss of energy than from using inside air.

.

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Wouldn't the colder more O2 dense air improve combustion?

cold air vs. fresh

you need fresh air in the house , the fan and dryer vent's will provide the difference that your stoves will use.

when I use my wood stove I need to open the window or door any way's in order to cool the house off.