Distributing wood burning stove heat

[nbaxley]

I have a 20'x30' old shed that I'm turning into a office/workshop. The office will occupy a 8'x15' corner of the workshop and be walled off and insulated from the rest of the workshop. I was given a fairly large wood burning stove by an uncle and I'm wondering how best to use it to heat both office and workshop. The office will be my home office and will house a couple of computers a desk and a couch. Right now I have no insulation and no walls put in and the stove is sitting in the corner not hooked up so I'm not fettered by any existing construction. I will be insulating the walls and the ceiling eventually. A couple of other factors. This is in central Illiois so the winters can get pretty cold. The roof is a fairly flat slant and pitches to the north only, it's just a one-way slant whatever that's called. There is a big sliding door on the east side that I'm not quite sure how I'm going to insulate yet. Several questions:

1) Is there a certain place to put the stove to get the best distribution. I can probably put it along the shared wall of the office and workshop to get a central location but I don't want to have it in the way too much. 2) Can I distribute the heat by routing the exhaust pipe through the building? Does that put off much heat itself and are the ways to help that along? 3) Are the are any precautions I need to take if I route the exhaust through the drywall walls from the workshop to the office? 4) Is it any better to send the exhaust out the wall than the roof?

I'm sure there are lots of other questions I should be asking as well so I'd really appreciate any insightes you've got.

Thanks, Nate Baxley

[Charlie Self]

Nate Baxley asks:

Share it.

Yeah, you can do that, but make darned sure the pipe used has a pronounced tilt towards the stove, or you'll have little puddles of creosote under every seam. Nasty stuff. The long pipe lets the smoke cool down so extra creosote condenses out. There used to be a fan that fit into the pipe--part of a section of pipe, actually--and that may be still available.

You betcha. Cement board (used to be asbestos when I was doing this) is needed to prevent heat transfer to the drywall.

Why would it be? I've done both. Check around and you'll see that chimneys generally come out of roofs, not side walls. Stove pipes can go either way, as can the newest stainless steel chimneys. A straight run is generally easier with a chimney. You really want to avoid bends where possible, as every bend, and, really, every uninsulated section of stove pipe increases the amount of creosote condensing from the smoke. Every bit condensed out either makes a mess, requires you to clean the pipe and chimney more often, or catches fire. I've had one chimney fire in my life. That's two more than I needed. Scared the crap out of me and my neighbors.

Charlie Self "Ambition is a poor excuse for not having sense enough to be lazy." Edgar Bergen, (Charlie McCarthy)

[Nova]

Yes.

Yes and yes.

Yes.

It depends on where the stove will be placed.

I suggest you check with a reputable wood burning stove retailer in your area. For proper venting of a stove there are a number of things that must be taken into account such as:

local building codes pitch of the roof near-by obstructions type of materials used the the building's construction

A good retailer may be able to suggest some DIY literature explaining these things if you wish to install the stove yourself.

Also consider installing a ceiling fan to aid in circulating the heat throughout the building.

-- Jack Novak Buffalo, NY - USA (Remove "SPAM" from email address to reply)

[Edwin Pawlowski]

While I agree in principle, I don't see it in practice. Spent some time this weekend in some old buildings such as Eleanor Roosevelt's Val Kill cottage, a few buildings at the Hancock Shaker village and they all had wood burning stoves. In every case, the pipe seemed to be about perfectly level and longish runs, from 8 to 15 feet.

Huh? I can show you hundreds of chimneys (including mine) that are on a side wall. They all do go above the roof not exhaust on the side if that is what you mean. Ed

[Andy Dingley]

I can show you several museums where wood burning stoves are incorrectly installed. It's something of a lost art and modern curators don't always do it right, just through modern ignorance. The American Museum in Bath has their Shaker stove assembled back-to-front!

If I did install a horizontal flue, I wouldn't do it within 10' or so of the stove, and I'd put rodding doors at each end.

[George]

Hooray! Right answer.

Longer the inside pipe, worse the draw for starting. I'd consider trying to share heat by locating the stove near a common wall and using a fan-driven, thermostatically controlled heat recovery type of device in the pipe to dump heat into the other space. Works very well for me. Means a vent down low to recirculate, of course.

Also, don't forget to rehumidify. All the air that runs up the chimney brings in lower humidity stuff from the outside. With four people, two dogs and a lint-filtered dryer putting moisture into our place we have a tough time keeping the humidity up enough to avoid URIs.

[Sweet Sawdust]

If I were doing this I would: Properly install stove "near "office, with stove pipe runing up through roof. Put "window" in wall of office and shop, place filter and fan in window to blow air into office. This will draw warm air from the shop into the office and give office slight postive pressure to keep dust from coming into office from opening door. small box fan (12"x12") drawing air form shop through filter should work. If stove is within 10' of fan you should have all the warm air you want, and can turn off the fan if office gets too warm.

[John Barry]

Amen to the first part. As to the second, for any current woodstove I've seen, 6-8 feet would be a reasonable limit for plain metal smokepipe, if only to be able to maintain draft. That length can materially increase overall efficiency per tests that have been reported. The longer it is, the less draft pressure differential, and the greater the likelihood of condensing crap inside the pipe. I'd aim for a "sweet-spot" there in trading draft (thus overall output, for one) for efficiency.

Some of the long uninsulated smokepipe runs in the past were used with very inefficient pot-belly coal-burners. Makes sense there, definitely not with wood.

HTH, John

[Howard]

Because you are going to use the office as a home office and include one or more computers I'd do the following:

1-Insulate the walls of the office including the wall between the office and the shop. I'd use at least R13 and try to get up to R19. With the price of all fuels deregulated in some fashion they won't be dropping very much.

2-I would seal the door between the shop and the office so that no dust or smoke get near the computers etc. You want a clean environment for the office?

3-I'd use a reliable automatic type of heat in the office. While electric resistance baseboard can be expensive if it is in a very well insulated room with a set back thermostat your office will be ready to use whenever you want at a somewhat reasonable cost. An alternative could be a thru the wall heat pump (either a "window" type unit or one used in hotels, schools etc). You save due to efficiency, get air conditioning (comfortable in summer) and have a higher first cost.

4-I'd wait on installing the wood stove. If you construct a well insulated and sealed shop your lights, dust collector and other continuous running items will be putting 1000 or 1500 watts into a tight building. My shop (Philadelphia weather) is set up this way and I use just another 1500 watt electric heater (no open element) and I can stay comfortable. Also consider a good bank of windows facing south with an insulating balnket to cover them in the evening (inexpensive solar collection concept).

5-If you do decide to add the wood stove first visit your building inspector and fire marshal and maybe your insurance agent. They will be able to highlight things like wall sheilds, double walled flues, etc. Finally just remember that wood stoves without a catalytic converter (yes the new stoves have them) are probably the most polluting heating fuel around and unless you make adequate provisions for make up air they are very inefficient and very drying. Finally how often do you want to go out and fuel the fire?