# Wood stove installation in basement, which already has gas furnace.



## gnawrot (Sep 1, 2006)

Hi,

I live in upstate NY and have some firewood available, which I want to burn in winter. I would like to install wood stove in my basement because basement is not insulated and I work in my workshop located in my basement. I have also gas furnace and gas hot water heater in the basement. Gas furnace is used to heat up water used in hot water baseboard heating system (which we like a lot). 

Gas furnace is located very close to chimney, which has two flues. One for gas furnace and hot water heater and the other for fireplace which is located on the first floor in family room. I would like to install wood stove in basement which would be close to gas furnace. Wood stove would not share the same flue with gas furnace. Wood stove would use second flue.

My basement is 1,300 sq.feet. I would like to have warmer basement and also I am hoping that warmer basement will make first floor warmer. I was planing to buy cheap (used) cast iron wood stove.

Here are the questions:
1. Is there a fire hazard with gas stove (and gas hot water heater) in the proximity of wood stove?
2. What BTU furnace do I need?
3. Is cast iron wood stove without blower good for this application?
4. Do I miss a lot not having a blower?
5. Can I put firebricks inside cast iron wood stove? Is it manufacturer/model dependent?
6. How far should I put the wood stove from gas furnace? Puting wood stove further away from chimney would decrease speed of combustion gases. This could influence other factors I guess.

I run search to find articles that would answer my questions. None of them seemed to address my case. I am newbie as far as wood stoves are concerned but I am handy and can tackle many projects.

If you could help me I would greatly appreciate it. Thank you.


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## buildafire (Sep 1, 2006)

Hi gnawrot!  Great questions for someone new to wood stoves.  First, thank you for taking the time to ask for help.  That is so important to the safety of your home when installing a fire yourself.  Second, I like to encourage do-it-yourselfers.  I also like to tackle projects myself.

Before I answer your questions listed above, I'd like to address one you didn't ask...  Is it okay to install the woodstove into the second flue?  Unfortunately, the answer is no.  You can't share two solid fuel appliances in the same flue.  I recommend that you look for an outside wall to install a new class A chimney out of, or locate part of a closet upstairs that you can frame in and use as a chase for a new class A chimney.  If you do that, here are the answers to the rest of your questions..

1.  There shouldn't be, as long as there are no gas leaks.  Of course, what do you mean by proximity.  If your cheap cast stove is an unlisted stove, you need at least 3 feet around it to combustibles.
2.  This is kind of tricky.  The older your woodstove, especially cast, the less efficient it might be.  Old cast stoves were put together with furnace cement.  Over time, that cement can become brittle, crack, create leaks, and make your stove uncontrollable and very inefficient.  If that's what you're buying, you will need a big one, maybe 3 cubic foot firebox...  and you will go through plenty of that wood you want to use up.  If you get a good air tight box that is clean burning, you may only need a 2 cubic foot firebox, maybe around 30,000 BTUs (EPA numbers) or so, and you will go through a lot less wood with less chance of creosote build up in your chimney.
3.  The blower would provide faster convection heat movement (hot air).  If your workshop is in the same room the stove would be in, radiant heat will be sufficient.  If your stove would be in a different room, the blower could help warm you up faster.
4.  The blower would give you faster warm air movement through your basement, but that's about it.
5.  Firebricks hold heat inside fireboxes and help protect the firebox.  If the stove wasn't designed with the firebrick, adding it could change how the heat moves out of the stove and could change the clearances to combustables.  I can't recommend modifying the stove from how it originally was built and tested...
6.  Again, you can't use either of the flues that you described, and I eluded to clearances in question 1 answer.  To more directly answer your question here,though, I would consider the other appliances combustible and give them plenty of room for future service...


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## elkimmeg (Sep 1, 2006)

#1 I will differ Bill d fire code requires 50 cubic feet of make up combustion air for every 1000 Btus of your applainces. Say your gas furnace is 100,000 btus,your gas hot water heater 50,000 and a stove is 50,000. You  would need  10,000 cubic feet to support proper combustion with 8' ceilings, you just about make it. If you have a clothes dryer  that removes 150 cfm  all  your  appliances will suffer
 What is the risk the dryer's demand? IT can back draft your appliances, pulling co and co/2 into your cellar and to your living space. Do you have a gas combustion dryer ? That has to be factored in its BTU  combustion needs as well as its forced removal of air

 Fire d bill is right you can't have two wood burning applainces serviced by the same flue.  However if you cut out a inlet thimble and run a *full liner*r threw the fireplace and damprer, blocking off the damper, it can be done You will have to deal with viewing the liner running threw you existing fireplace.  Not the easiest task for most home owners.

There are codes that govern location  or called proximity.  You can not expect  fuel burning appliance to run properly when it is competing for  the same combustion air in the same proximity. If you do proceed you, should have some separation distance
Another solution that solves proximity and combustion air, bring in an outside air feed and feed you largest appliance demand, probably your burner.

One other word of caution, you say you have a shop in the cellar. What are you doing down there? Saw dust airbourn can be very combustiable.  Oil based any  kind of paint Lacqures very combustiable. NFPA address installation of a solid fuel burning applainces in dangereous locations, in fact prohibbits them in garages, for that very reason.  The wood stove adds new dangers because, to an extent, it is an open combustion with a clear open air feed. You hotwater heater and furnace are closed combustion chambers.

Welcome aboard great questions. It can be done but  good planning is needed


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## wg_bent (Sep 1, 2006)

gnawrot said:
			
		

> Hi,
> 
> I live in upstate NY and have some firewood available, which I want to burn in winter. I would like to install wood stove in my basement because basement is not insulated and I work in my workshop located in my basement. I have also gas furnace and gas hot water heater in the basement. Gas furnace is used to heat up water used in hot water baseboard heating system (which we like a lot).
> 
> ...



Nice to have you aboard.  Some interesting questions.

1.  Not if the gas appliances are leaking.  I'd keep the wood stove a couple feet away to allow for servicing the gas appliances, plus allow for enought clearance due to heat.
2.  I thought the furnace was doing o.k. already, so I'm not sure on this one.
3. If the area is completely open it should work o.k.,  but a blower will get the heat distributed faster.  If you want the upstairs to get some heat, is there insulation in the floor joists?  If so, you'll get a lot less.  Stair proximity seems like it would also be a factor.
4. Some
5. If the stove wasn't designed to have firebricks in it, I wouldn't add them.
6.  The height of your chimney is the most important factor in getting good draft.  Is that your concern?  

One more thing.   You refer to this as your shop.  What kind of shop? Be very careful if it's a woodworking shop.  The presence of wood dust in the air from sanders, table saws, planers etc... can be unbelievably explosive when exposed to open flame.  I think a wood stove qualifies especially when it's opened for reloading.  I know of a local (well local when I lived in Endicott, NY) custom furniture shop that had a wood stove, and the whole thing blew up and burned down...twice.


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## gnawrot (Sep 1, 2006)

For second question, I meant what BTU rating do I need for a wood stove to heat up 1,300 sf basement? Basement is approximately 8 feet high.

I do have some saw dust and don't paint now (I don't plan to do either). Wood workshop is on opposite side of basement and is on the opposite side of gas furnace.

Thank you very much for all replies. Awesome forum (by that I meant poeple).


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## Rhone (Sep 1, 2006)

Besides the other things, like losing the ability to use the fireplace on the main floor if you do this and seeing a tube running through it instead.  After dealing with stoves in uninsulated basement, it won't take you long to figure out there's no chance of using it to help heat your house without insulating the foundation.  The foundation sucks so much heat you have to feed it constantly.  The second you stop, the basement drops right back down to the temperature it was before.  Hearthstone, a popular stove maker says this with all their stoves. 



> We recommend that you do not locate your stove in an uninsulated basement.  The amount of radiant energy required to heat concrete basement walls is so great that most of the useable heat is aborbed by them and lost".



I started with a stove in my basement.  It didn't take me long to realize I was having trouble keeping my basement warm and the heat wasn't going upstairs either.  I insulated it, that helped things a lot.  If you don't insulate it, the second the fire stops you can practically sit and watch the temperature needle move back to where it was before.  Just 1" of the rigid foam insulation (extruded polystyrene) at R5 insulates better than several feet thickness of concrete.  But, using it you'd need to cover it with drywall, it's flammable.


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## gnawrot (Sep 1, 2006)

I have baseboard hot water heating in basement and I also noticed that warmed up basement would loose heat very quickly once heat was turned off. Keeping warm basement makes gas furnace work quite a lot. Copper pipes are always hot. This tells me that gas furnace heats up water through basement zone most of the time. 

Some concrete walls are above grade level on the north side. Probably, this wall will get cold in no time. 

So I guess I will have to insulate basement to really benefit from wood stove. That makes sense. I was thinking about this. Thanks for the tip.

EDIT: It would not make sense to put gas furnace liner through second flue in case I wanted to install insert in family room. So I would have to install liner from basement to garage up to attic and through the roof.


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## begreen (Sep 1, 2006)

Just curious, have you considered putting a stove or insert in the fireplace? What is the ultimate goal here, to heat the basement or to heat the whole house? If the basement need is occasional, I'd insulated it with foamboard and heat the desired area electrically only when it's needed. With a stove in the family room, you will get to enjoy the heat and get to watch the fire.


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## gnawrot (Sep 1, 2006)

I have some fire wood available so I figured that I would use wood stove to warm up basement (don't want to take fire wood home to avoid mess). I have 2 story house with walk out basement.  Some concrete walls are outside 2 feet high along the house and one side is exposed (like triangle - grade goes downhill on the northern side). 

I guess I might install insert in family room and try to warm up first floor with it. Once I insulate basement I might add wood stove next year.


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## begreen (Sep 1, 2006)

> I guess I might install insert in family room and try to warm up first floor with it. Once I insulate basement I might add wood stove next year.



It will have to be either or. Two heating appliances on one flue is not allowed. It sounds like you are trying to do this inexpensively, but first and foremost, a woodstove really needs to be installed safely.  Take pictures of both the downstairs locale and the family room fireplace and post them to the site. Have the chimney inspected to be sure it is in good shape and to determine it's capacity. Is this an iinterior or exterior chimney. 

There are options, but we all want you to be safe and happy and posting smiles after you're done. It would be a good idea to have a pro come in and inspect the setup and give you a quote.

PS: There's a nice used stove for sale on this site in the for sale section - blue VC Resolute, just rebuilt. It might fit in your fireplace for now and then maybe migrate to the basement later on?


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## gnawrot (Sep 1, 2006)

Two wood stoves will not share the same flue (I don't think it is safe). My chimney is an exterior chimney and is in good shape. I repointed it last year and replaced broken flue. Broken flue cause mortar to detoriate. I poured concrete chimney cap and installed it on the top of chimney. I sealed chimney cap with permeable Ditrich brick sealer.

Of course I am trying to be cheap but I want to be safe as well.


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## Rhone (Sep 1, 2006)

As for the insulating, any exposed foundation or, for the most part any foundation from the frost line up should be insulated.  If your foundation is 10" thick, it's providing R0.80 in total for insulation, and considering you have a walk-out with plenty of exposed foundation to the outside your basement must be freezing!  My house now is just like yours, built into a hill where the back is a walkout and it's costing me about 40% of my heat loss.   I'm in the process of replacing the basement windows with triple-pane or Low-E Argon and then I'm going to insulate the outside walls of my basement.  It's better if you do the outside walls because it puts the thermal mass inside the living area, it also doesn't take away from living space and for me, with a finished basement already it's just going to be easier for me to do the outside particularly since, with a walk-out there isn't dirt against half the foundation anyway.  

If insulating the inside make sure you insulate it properly else you risk creating a mold/mildew problem.  For example, you shouldn't put in a 2x3 stud wall right against the foundation, then fiberglass batt insulation between the members, and cover that with drywall.  Not in a basement, you should put 1" XPS (comes in 4x8 sheets of baby-blue or pink foam) directly against the foundation first, it's R5 then put the fiberglass over that and then the drywall or simply get enough XPS for the R-Value you want, put furring strips between, and cover it with drywall.  XPS & fiberglass batt sure aren't as cheap as a couple years ago.


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