Basement Insert - How Much Convection?

[AdamE]

Hi all, I'm planning on putting a wood insert into my walk-out basement. That room is approx. 750 sf. There's an open stairway to the first floor and was just curious how much heat transfer I can expect.

The reason I ask is because I'm having trouble deciding what size insert to get. I was looking at an Osburn 1600 or similar which is for up to 1500 sf. I realize that there prolly won't be too much without air returns of some kind, but I've heard differing opinions. I also don't want to cook myself out of the basement.

Does anybody have any experience with this kind of setup?

Thanks!

 

[mellow]

Are the walls insulated?

 

[Grisu]

House heating from basement installs can be tricky. Some work, others don't and it is sometimes hard to tell why the difference. A small fan placed at the top of the stairs blowing cold air downwards can help get the heat distributed. How far is the fireplace from the stairwell? Is the basement finished and insulated? How airtight is the house? How many sqft including the upper floor do you want to heat? Are you anticipating heating the whole house with that insert? The Osburn 1600 may not be enough for that.

To see how well the heat travels: Do you have a way of cranking up the heat downstairs so you can check if warm air flows up the stairs? Maybe with some space heaters?

 

[AdamE]

I'm in the initial phases of finishing the basement. The walls will eventually be insulated. The upstairs is as insulated as you'd expect a 1957 rancher in S.E. Pa. to be.

The stairs are about 16' from the fireplace and the heat is disconnected. It would take a lot of space heaters to be able to detect any movement.

I'm just hoping to supplement my oil/cast iron baseboard heat in the living room, dining room and kitchen as well as the basement. The bedrooms are on the other side of the house and I'm not expecting to do much for them. Although, I have toyed with the idea of putting small vents and returns up through the floors of the bedrooms with small muffin fans helping airflow. I don't like the idea of cutting holes in my oak floors though.

Here's a question... if I buy a larger insert with the hopes of heating the upstairs and then find out that it's not working, will I be able to just use less wood and close the air vent down so I don't cook us out of the basement? Or are there limits as to how low you can go?

Thanks.

 

[Grisu]

The stairs are about 16' from the fireplace and the heat is disconnected. It would take a lot of space heaters to be able to detect any movement.

You would see it as an onetime experiment. Run them for an hour or so and see at the top of the stairwell if you can feel warm air coming up. Depends if your circuit can handle it. May cost a few $ in electricity but buying a wrong-sized stove will be much more expensive.

I'm just hoping to supplement my oil/cast iron baseboard heat in the living room, dining room and kitchen as well as the basement. The bedrooms are on the other side of the house and I'm not expecting to do much for them. Although, I have toyed with the idea of putting small vents and returns up through the floors of the bedrooms with small muffin fans helping airflow. I don't like the idea of cutting holes in my oak floors though.

If you spend most of your time upstairs, putting an insert/stove there may be the better option. With some well-placed fans you may be able to distribute the heat across the whole upper floor. If you like you can post a floorplan for some tips regarding heat distribution.

If you put vents in the floor make sure they are compliant with your local fire code.

Here's a question... if I buy a larger insert with the hopes of heating the upstairs and then find out that it's not working, will I be able to just use less wood and close the air vent down so I don't cook us out of the basement? Or are there limits as to how low you can go?

You don't want to close the air control so much that the fire starts smoldering. What you would do is to put less wood in to make a small, hot fire and probably not run the stove all the time. Not the most efficient way of running a large insert, though, as you will spend more time with small startup fires to heat up the stove and flue again. Potentially also higher risk of creosote. Dry wood will be key as usual! Do you already have several cords of wood split and stacked in your yard for next winter?

Another option to think about: Get a medium-sized insert with a firebox of 2+ cu ft for a consistent overnight burn (meaning you will still have enough coals in the morning for an easy relight). The Osburn 1600 is a tad small in that regard. If during the first winter you feel the heat is going upstairs and you would benefit from a larger insert, sell it and get a larger one. You still can use the liner then and probably do the install yourself with some friends. How large is actually your fireplace?

Regarding both options you may potentially spend more money than you need to. Buying a larger insert and then only running it with small loads would be a waste. Buying a medium insert to swap it out for a larger one soon thereafter would also cost you more. It comes down to what has a better chance of working right away in your opinion.

Some tips regardless of insert size:
If it is an exterior chimney definitively use an insulated liner. Draft will be better and less risk of creosote. For an interior chimney it is still highly recommended.
Have a sweep clean the flue and take a look at its current condition.
Put a block-off pate in to keep the heat in the room: https://www.hearth.com/talk/wiki/make-a-damper-sealing-block-off-plate/
If the fireplace is at an exterior wall think about putting Roxul behind the insert: https://www.hearth.com/talk/threads/finally-got-around-to-insulating-my-fireplace.75755/
Keep reading and posting around here for more advice and help.

 

[AdamE]

Thanks for the info!

I'm now looking at something along the lines of an Osburn 2000. Not too big and it still goes down to 500 sf, but gives me the flexibility of more BTUs. It's 2.4 cubic feet.

Yes, I've got over a cord stacked just from trees that fall into my yard from the State Park. They often take out my power lines, but that's a whole different story...

As far as my chimney goes, it's an internal chimney and it's about 21'. I've already talked to a couple of manufacturers and a dealer and they all agree that because my flue is 8" x 13" Terra-cotta and the inside dimension is 6-1/2" wide, that I could go with 5-1/2" flex without insulation (or even 5" smooth wall). I'd try 6", but I can see the mortar joints in the clay stick out a bit and I'm not a gamblin' man. Also, the clay is in good shape.

BTW, the fireplace is plenty big. It's 36"x28"x 22" deep. It's got an 18" deep stone hearth too.

Have a good one!

 

[HatCityIAFF]

i run my 1402 (2.3ish firebox) out of my finished insulated basement (raised ranch) its across the room from the stairs, maybe 20 of so feet. The heat goes up the stairs to a catherdral ceiling, which has the dining room and kitchen attached. down the hallway are 3 bedrooms. If its sub 15 degrees out, I cannot get the downstairs 400sq ft over 78 degrees, no matter how hard i push the stove. I simply loose too much heat up the stairs. Mind you there is a 10 degree difference from downstairs vs. upstairs, so the heat is going up there, just not much of it. I would say go with the biggest you can handle, like the 2400.

 

[velvetfoot]

There are combos where some heat is radiated in a scenic manner, like in your basement, and the rest is distributed by water like your boiler, like to the upstairs radiators. More complicated and dollars, I imagine, but I could see it. I think they use smaller size wood, and I have no idea of the firebox size and stuff like that. A contributor here, passionforfire&water, sells them. http://www.hydro-to-heat-convertor.com/

 

[mstoelton]

In my experience - not much will go upstairs. I have a basement install (Clydesdale). Love it but decided last winter to install one upstairs as well. Now the whole house is toasty warm when the inserts are running.