new ducting

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.

arro222

Member
Aug 2, 2013
89
RI
I am considering a wood furnace to heat 1800 sq ft log home. Currently have a wood stove but want to keep a cellar installation. The problem is that this home is hydronic with no ducting at all. Wood boiler systems that would supplement my oil fired unit are 10K and thus too much of an expenditure for me.
I could do ducting myself but I can't find any simple pics of how to lay this out as a retrofit.
I called a contractor but they want 7K to put in ducting and then when I stated it was for a wood furnace, they declined the job saying it would be too difficult to regulate and balance. This was getting too expensive as well as I would be approaching 10K anyway after the furnace cost
I don't know what other people have done with wood furnaces as a retrofit -add on, but it can't be all that difficult. My mind just has to wrap around it with a pic or two that I cannot find on the internet. Thank you
 
I am considering a wood furnace to heat 1800 sq ft log home. Currently have a wood stove but want to keep a cellar installation. The problem is that this home is hydronic with no ducting at all. Wood boiler systems that would supplement my oil fired unit are 10K and thus too much of an expenditure for me.
I could do ducting myself but I can't find any simple pics of how to lay this out as a retrofit.
I called a contractor but they want 7K to put in ducting and then when I stated it was for a wood furnace, they declined the job saying it would be too difficult to regulate and balance. This was getting too expensive as well as I would be approaching 10K anyway after the furnace cost
I don't know what other people have done with wood furnaces as a retrofit -add on, but it can't be all that difficult. My mind just has to wrap around it with a pic or two that I cannot find on the internet. Thank you
I had a thermal control unit that heats my domestic hot water in the furnace which is also used for my baseboard heat. It worked great its name is thermocontrol or thermal control one of those yes. I use it for five to seven years then went with pellets just because I got tired of hauling the wood around. Oh and you do not split the wood you put the logs in hole logs probably biggest diameter is going to be 10 or 12 in length 28". I had one like this. Besides producing tons of heat it moves the water to and from furnace with small pump. http://www.nationalstoveworks.com/m.hotwaterstoves.html
 
Last edited:
I am considering a wood furnace to heat 1800 sq ft log home. Currently have a wood stove but want to keep a cellar installation. The problem is that this home is hydronic with no ducting at all. Wood boiler systems that would supplement my oil fired unit are 10K and thus too much of an expenditure for me.
I could do ducting myself but I can't find any simple pics of how to lay this out as a retrofit.
I called a contractor but they want 7K to put in ducting and then when I stated it was for a wood furnace, they declined the job saying it would be too difficult to regulate and balance. This was getting too expensive as well as I would be approaching 10K anyway after the furnace cost
I don't know what other people have done with wood furnaces as a retrofit -add on, but it can't be all that difficult. My mind just has to wrap around it with a pic or two that I cannot find on the internet. Thank you

This could be a very easy proposition depending on your layout, available head room down there....

A couple short supply runs off a plenum, ductless return puling air down a stairway?

So more info or diagram, and maybe pics of where it would go might help.
 
  • Like
Reactions: lost in the woods
Hmm, this is pretty good jerrieric. Much less expensive than the units I was looking at. How was this thing with wood usage? I'm using 5-6 cord per year now.
I read a review that one guy was using 12 cords with one of these but he was heating over 5000 sq ft. Mine is about 2200 including the cellar. Should do about half of this guy's usage no?
 
I am considering a wood furnace to heat 1800 sq ft log home. Currently have a wood stove but want to keep a cellar installation. The problem is that this home is hydronic with no ducting at all. Wood boiler systems that would supplement my oil fired unit are 10K and thus too much of an expenditure for me.
I could do ducting myself but I can't find any simple pics of how to lay this out as a retrofit.
I called a contractor but they want 7K to put in ducting and then when I stated it was for a wood furnace, they declined the job saying it would be too difficult to regulate and balance. This was getting too expensive as well as I would be approaching 10K anyway after the furnace cost
I don't know what other people have done with wood furnaces as a retrofit -add on, but it can't be all that difficult. My mind just has to wrap around it with a pic or two that I cannot find on the internet. Thank you

I have a nice used EKO 25 available. Comes with a 500 gallon stainless storage tank. Excellent condition.
 
I've been in contact with Drolet. They said their unit needs at least 6 feeds out of their 10 stack manifold so it would not over-heat. I was thinking of 3 feed registers and one return register but they said would be a no go. Plus their sizing is for 8" round duct which would be problematic for head space down there.
I asked about doing an 8" manifold with 4" feed duct. they stated that would be ok if the reduction was at the far end of the feed.
So now my head is all bunged up on how to do this.
 
I am considering a wood furnace to heat 1800 sq ft log home. Currently have a wood stove but want to keep a cellar installation.

Running a wood furnace with no ducting is just like running a big wood stove. The drolet requires at least 6 of the 10 knockouts in the furnace plenum to be open. Big deal. Just open 6 of them and run it. You can attach ducts to none, any, or all of those openings.

You can also remove the goofy octopus plenum and install a regular single big duct. The single big duct has a specified range of allowable sizes in square inches.
 
Running a wood furnace with no ducting is just like running a big wood stove. The drolet requires at least 6 of the 10 knockouts in the furnace plenum to be open. Big deal. Just open 6 of them and run it. You can attach ducts to none, any, or all of those openings.

You can also remove the goofy octopus plenum and install a regular single big duct. The single big duct has a specified range of allowable sizes in square inches.
lol. it is rather goofy looking. I don't want to duplicate a wood stove. I'm looking to get heat distributed more efficiently. The trouble here is that they seem to be using 8" round ducting which I would have trouble with clearance wise in the cellar.
I'm just ignorant enough about the subject not be able to come up with alternative ducting methods.
 
lol. it is rather goofy looking. I don't want to duplicate a wood stove. I'm looking to get heat distributed more efficiently. The trouble here is that they seem to be using 8" round ducting which I would have trouble with clearance wise in the cellar.
I'm just ignorant enough about the subject not be able to come up with alternative ducting methods.

I’m almost certain that the knockouts take 6” ducts. You really don’t have enough headroom for a little 6” duct?
 
I’m almost certain that the knockouts take 6” ducts. You really don’t have enough headroom for a little 6” duct?

No, I have room for 6" duct. The knock outs are 8" on the Drolet. Granted, they do look smaller in pics of the unit but the company rep stated they were all 8"
 
I have the heatpack and am at the point of trying to figure out my layout. I was initially thinking of doing 4 runs until I read the manual closer. they are definitely all 6" ports. the octopus isn't ideal from a visual standpoint for sure but I don't have the room to do another main trunk line in the basement since I already have a forced air system in the house, whose trunk line is underpar to just patch my furnace into :(

Is there a material I could get to attach to the floor joists that would allow for closer mounting of the ducts to the ceiling until I get far enough away that CTC's allow for it? at least two ducts are gonna have to run across the ceiling at the bottom of the steps which is only maybe 4-5' from the furnace. I would like to keep them as tight to the ceiling as safety allows.
 
Is there a material I could get to attach to the floor joists that would allow for closer mounting of the ducts to the ceiling until I get far enough away that CTC's allow for it? at least two ducts are gonna have to run across the ceiling at the bottom of the steps which is only maybe 4-5' from the furnace. I would like to keep them as tight to the ceiling as safety allows.
What is the listed CTC for the ducts in the first 5'-10'?
Just spitballin here...you could put up some ceramic insulation...like the stuff that they use on chimney liners...that has the HD foil layer on the outside.
Another option...a little DIY...put up a 7 or 8" duct...run the 6" through it...you could bend up long strips of 1" wide sheet metal in a zig zag pattern...slide them in between the 6" and the 8" to center things up...kind of like an air cooled triple wall chimney pipe (only double wall, not triple)
 
Is just use 1” thick unistrut I’d you need 1” clearance between duct and the joists.

Respect the clearance requirements. Don’t cheat. People could die.
 
Is just use 1” thick unistrut I’d you need 1” clearance between duct and the joists.

Respect the clearance requirements. Don’t cheat. People could die.

I had zero intentions of cheating the CTCs, that’s why I was asking about legit ways to reduce them if possible. Since the basement is unfinished I figured if there was a material that would protect the joists that I’d use that where needed.
 
  • Like
Reactions: Highbeam