Channeling woodstove heat to a basement family room

[spaztek24]

Before my husband creates some kind of dangerous backdraft (or just wastes his time and money) I'd like to post here the specifics about what we're trying to accomplish. It seems as though there are lots of resourceful and knowledgeable people on here that can give me a correct answer!

Our house is a ranch of about 1200 sq ft. of living space on the main floor with cathedral ceilings throughout most of the house. We also have 800 sq ft of additional living space in the basement that we've been heating with nothing but electric space heaters. The woodstove is directly in the middle of the main floor of the house, built into an enclosed brick hearth that radiates heat in the same room that also has cathedral ceilings, and does a fine job of heating the entire main floor living space. However, the house is so well-insulated that the temperature climbs rather high in the area with the cathedral ceiling (which is fine by me, not a problem). What we'd like to do, obviously, is channel some of this heat that gathers in the high-ceiling area and get it somehow downstairs into the basement family room. My husband thinks that using a bathroom-type exhaust fan and ducting it into the downstairs room will solve the problem. Is it as simple as piping an exhaust fan in that catches the hot air and pulls it downstairs, or am I missing something? Thanks in advance to anyone who can respond!

Stacey

 

[Redox]

It's something, but I doubt that you will be happy with the results. The average bathroom fan is only about 100 CFM and this might do one very small and well insulated room if it were connected to a furnace that is putting out 120F heat. Since I doubt your ceilings are getting that hot, you will need more volume. You could get a bigger fan, but you will also need a lot larger duct; 8 inches and 400 CFM wouldn't be overkill. Then there's the draft from the air that is only 85-90F. It will raise the room temperature up some, but I don't think it's really going to do what you want.

What might work better would be to set up a fan to suck the cold air off the basement floor and blow it through the ceiling towards the stove. Others here will tell you it is easier to push cold air towards the heat rather than the other way around. This also puts the drafty part into the warmest room. If this seems to help, then you can decide whether it's worth the trouble to put the duct all the way up to the cathedral.

A ceiling fan in the cathedral will help even out the temps upstairs, counteract the cooling effect of the fan and actually warm up the first floor. It may also allow you to cut down on wood consumption as the heat loss in the ceiling is magnified by the high temperatures up there. It's worth a consideration later...

Hope this helps.

Chris

 

[oconnor]

Pumping any air (warm or cold) is going to be difficult to achieve if the cold air in the basement has no where to go, and being that it is cold air, it wants to go down (aka stay where it is in the basement)

I am also looking to warm my unheated basement more, and here is what I have found out so far - if I take the coldest air from the basement floor and move it to the main floor where the stove is (Blowing it up the stairs with a monster fan from the basement floor), then warm air starts to move down the stairs along the ceiling of the stairway. Given that, I plan on first ducting a fan forced cold air supply into the room where my stove is, and I will see how that works. If that helps some, I will then look at assisting the flow of warmer air from the main floor that is trying to replace the cold air I removed with the fan/duct.

Watch where the air goes on its own first, try one path at a time, and see how airflow changes. Then use technology (fan/duct/etc) to reinforce what the air wants to do already.

Lots more posts on here about the subject of moving the heat around. Look them up and give them a read (with you husband too )

 

[spaztek24]

Thanks for your responses! I shared them with my husband and he's doing some re-thinking. We do already have a large ceiling fan mounted at the tip-top of the cathedral ceiling but I tend not to turn it on since doing so results in temps over 80 degrees in the living space and bedrooms....however I havent yet done a temp reading in the basement room whilst using the upstairs ceiling fan simultaneously, so that will give me something to experiment with this evening!

Another key point to mention that I haven't already, is that we installed a forced hot-air propane heating system 5 years ago when we bought the house. We mainly use it in the summer to run central a/c, but seldom do we need it for heating purposes in the winter months due to the woodstove. Another possible idea he's playing with is to cut additional heat registers in the cellar where the ductwork runs already, and then using the fan feature of the boiler to circulate air throughout the entire house and even the temps out. Again, this sounds too easy to be true, and I wonder if the constant humming of the boiler fan will drive me to smash it with a baseball bat. I will browse around the site some more and see if there are any posts on this particular option.

 

[BrotherBart]

My office is in our unfinished basement. I have a wood stove down here and on the main floor but sometimes I don't want to fool with tending two stoves and the big boy upstairs tends to overheat the place. Last winter I went to the warehouse and got the LM18R high velocity fan that we use in the summer and aimed it down the basement stairway. In no time the basement was nice and warm and the temp upstairs came down to a comfortable range.

Point being, you can move warm air down but that fan I was using is 3,450 CFM on low. And not the quietest thing in the world. And it blocked the door.

So it isn't the answer you are looking for but it is proof that you can move warm air down. But it takes brute force.

 

[oconnor]

3450 CFM! That is truly brute force! That is like emptying a 20x20 room with 8 ft ceilings evey minute. Cool.

 

[DoubleClutch]

I would find a way to pump cold air from the floor of the basement through some sort of duct, and exhaust it preferably near the ceiling above the stove, in such a way that it complemented rather than fought any convection currents already present with existing ceiling fans, etc.

Hose that stove down with the cold bilge water from the basement! That'll mix things up!