wood stove, fresh air intake size?

[FTG-05]

What size is on the wood stove?

On my Englander 30-NC, it was 3". I put in an AL 4" duct to feed it, mostly because that's what used in the ZC fireplace the 30-NC replaced.

I have no idea why an OAK would be "controversial". Not having it on a solid fuel appliance in a home is beyond moronic.

 

[RNeumann]

I was thinking the fan might get the secondary burn going better, and it could be turned off and on as needed.
I was also thinking smaller than 4". Stoves don't use much air. Is 4" used because it is cheap and availiable or is that much area really needed? The smaller the hole I drill through my foundation wall, the happier I'll be.

4” vent terminations are so cheap and plentiful it would be hard to find an easier size to terminate

 

[Oaktree]

Not[/U] having it on a solid fuel appliance in a home is beyond moronic.

Kind of strong words don't you think?
Maybe modern houses are airtight enough that an outside air source might be necessary, but plenty of us live in older homes that provide plenty of air. I've never had a problem in over 40 years of heating with wood.

 

[Raspy]

beyond moronic.

I'm looking out there and I can't see what is beyond moronic. Where is that and what is it called?

 

[Paddy]

Most houses are not so tight a wood stove won't run. The power a fire to draw oxygen is very great, think of egg getting sucked into the bottle. But there lies the problem, it will suck air from any tiny opening. Like around windows and doors, and hood vents.
So an outside air source is just letting you select where air comes in. For example if you had a wood furnace in your basement. It's either going to suck air from upstairs or from your dedicated pipe. So if you had a pipe going through the wall in your basement with a "reverse flap" and was not even connected to your stove, you have made an improvement. Placing it within a foot or two is even better. Using the aluminum dryer with magnets stuck to your intake is even better yet.

My wood stove was in a utility room with a dog door. When I'd open the wood stove door, the dog door flap would swing in. A self balancing set up. My fireplace, I used the ash door that I installed a pc of down spout from the back. When not using the fire place, I covered it.

 

[FTG-05]

Kind of strong words don't you think?
Maybe modern houses are airtight enough that an outside air source might be necessary, but plenty of us live in older homes that provide plenty of air. I've never had a problem in over 40 years of heating with wood.

Not at all.

Think of it this way: It's 20 degrees outside. You're trying to warm your house. You go and drill a 3" hole in your main bedroom wall and install a 40-85 cfm fan blowing cold air into your home.

That is beyond moronic. Yet, that's exactly what people are doing when they run a fireplace and/or wood stove without an OAK. No house is a vacuum chamber. The wood appliance is creating draft - which means air is going out of the house. Where does the makeup air come from?

The house being airtight is largely irrelevant, which goes to show most people don't even understand the issue.

 

[dmccarty]

Our wood stove has a 3 or 4 inch air supply duct. When we built the house we had a 6 inch PVC pipe installed that runs from the nearest outside wall, under the slab and pops up behind the stove. The plan was to directly connect the supply air to the stove but we found out we don't need to make the connection.

When the fire is running, the stove pulls in the combustion air it needs from the supply pipe. I can put my hand over the opening and the amount of air being sucked into the house is amazing. :shocked: As the fire burns down, less air is needed so the whole installation is self regulating. Since the air supply is behind the stove we never feel any cold from the out side air. :thumbsup: My FIL built his fireplace in a similar fashion except he had the air supply terminate in a floor register in FRONT of the fireplace. It worked real well too. Never felt any cold air come into the house with either setup.

The problem with NOT having an dedicated air supply is that the fire has to have air to burn and it will pull air from warmer areas of the house to get that O2. Our city house had a fireplace but we would not used it because it would pull the warm, heater air from the other side of the house and make those rooms COLD. The living room was nice and toasting but at the expense of the bedrooms. S...ty design but many/most homes are built that way.

I would NOT have a fireplace/wood stove without a way to supply it with outside combustion air.

Later,
Dan

 

[randy41]

can one of you non-moronics provide some scientific proof that what you say is true? i never have had a fresh air intake for any wood stove. i've been heating with a wood stove since the early 80's.

 

[flingwing1969]

It really depends on the home. I have usually never had the need for an independent outside air source with my wood stoves because the volume of the home is large and/or because the place was so old you could throw a cat through the gaps in the walls. Yes, if you are drawing combustion air from the home, you will feel a slight draft that might be uncomfortable and attempting to heat with an open fireplace in a conditioned home will be a heating negative due to the fireplace's inefficiency and the issue of heated air being used for combustion and going up the chimney.

In my current home, I had a large whole-wall masonry fireplace and now have a Jotul insert in it. I use the old ash collection in the back of the insert for combustion air and it is quite large. It works well and I've never had a need to measure its flow.

 

[Ford850]

can one of you non-moronics provide some scientific proof that what you say is true? i never have had a fresh air intake for any wood stove. i've been heating with a wood stove since the early 80's.

Not picking sides here, but any air going up the flue/chimney is coming from the fire box. The same amount of air going out through the flue has to be replaced, so its coming from either the room/house, from an indirect outside source (like I listed earlier) or from an OAK. If it's coming from the room, that air then has to be replaced which typically is through cracks and crevices around doors and windows. There's no way around it, a fire will be consuming air.