Wood Burning Furnaces

[Archena]

I've been reading up on these. Has anyone ever used one? Alabama has a mild (by Yankee standards) climate but I am extremely cold adverse. Mr. Power Bill reflects my distaste for cold - I'm probably the only Alabamian whose power bill goes up in winter! Anyway, I was wondering about these.

So, opinions?

[RTflorida]

Re: Wood Burning Furnaces

I can't really comment on a wood burning furnace, I'm guessing it is a wood stove that has been modified with a heat circulating (blower) system. The only thing I have seen similar is the fireplace my brother did about 25 yrs ago. About that time heat circulating fireplace inserts were becoming popular. Being an electrical engineer, he decided to build his own system when he did a family room/dining room addition with a fireplace. My memory is sketchy on this, but basically it involved a narrow chamber (for lack of a better term) that surrounded the sides and top (outside of the actual fire box) that captured the radiant heat. To this he added electricals similar to any furnace as well as a duct work system that I believe was tied into his existing gas furnace duct work (I may be wrong, it may have been entirely separate). In any case, it was pretty effective at heating the entire house. He lived in southern VA at the time, so not quite as mild as AL. The best part (and I have no idea how he did it) - the system was totally code compliant, passed heating/AC, passed electrical, and met national firecode. He was really proud of that. Hey, the entire addition cost him alot of money, he NEEDED it to pass.
I just wish I had gotten to see it more than once before he divorced and sold the house.
I was recently married, working 70 hrs a week (and still broke), with no time to visit (I was living in OH at the time).

So, long story, not so short.....In a mild climate with a good cheap source of seasoned hardwoods, I think you could effectively heat a portion/all of a home.

RT

[Archena]

Re: Wood Burning Furnaces

Thanks. Your brother's heating system sounds really interesting.

The furnace systems use water as the transfer medium. Water surrounds the firebox and is pumped between the house and furnace using a heat exchange to go from water to forced air (not sure how radiant heating is handled but it can do that as well). Depending on size furnaces can heat one or two buildings.

In Alabama getting rid of wood is usually the problem. The systems I'm looking at combust pretty danged efficiently which eliminates creosote.

[lwalper]

Re: Wood Burning Furnaces

Ya, they work GREAT. Can heat your domestic water with it too if you really want to see Mr. Watt go for a hike. Sure, you've still got to pump a little water from the heater to the house, but a small pump running virtually no head = "Goodby" to Mr. Watt. The only downside might be when the power goes out and the pump stops. Of course, your central system will go dead at that time too so ... time for your woolies.

I was visiting for a few days in a large home up in New Hampshire where they used this system with hot water radiators in each room - cold outside, toasty inside.

[chuckster]

Re: Wood Burning Furnaces

We have several houses around here heated with wood furnaces and they seem to work quite well. Using them for hot water is good in the winter, but who wants to keep the wood burning all year? I would switch back to a gas water heater when you didn't need the heat.

A small generator will keep the pump running in the event of a power failure.

Make sure you insulate the pipes running to the house well. That's where you can lose a lot heat.

[Archena]

Re: Wood Burning Furnaces

Thanks, guys.

I actually prefer on demand water heaters so that's not an issue for me. But if it can heat water it should be able to handle a heat exchanger - I'll look into that if I decide to go this route.

[fornax hominus]

Re: Wood Burning Furnaces

There are 2 types of furnaces in production now , A wood/ oil combination hot air type that replaces a gas or oil furnace , or the ''outhouse '' variety , free standing .. they use a liquid glycol solution , not water with a heat exchanger or in floor heating at the other end ... but .. but these things are big polluters , because the firebox is surrounded by a fluid bearing casing it never, never attains the high temps needed for complete combustion , and people load ' em up with all kings of huge logs , then shut them down and stink up the whole area , make sure you put it down wind ... For more info on the physical and the political aspects of heating with wood I recommend The Woodpile ? Discussing the Future of Wood Heating
cheers , stay warm.
tim

[Fish Wheels]

Re: Wood Burning Furnaces

You can get more information here:
Outdoor boilers; today's most controversial wood heating technology

Rod

[fornax hominus]

Re: Wood Burning Furnaces

Both of the above links were initiated and moderated by John Gulland a.k.a .. the ''Wayne Gretzky of wood stoves'' , wood burning enthusiast, WFO owner, and a long time neighbour and buddy .
tim

[dmun]

Re: Wood Burning Furnaces

I know it's a lot more of an endeavor than a wood burning furnace, but Masonry Heaters have a lot going for them. Like wood fired ovens, they burn hot and clean, then the fire burns out and the heated masonry heats the house for half a day or more. I haven't built one, but I think anyone who could build a pompeii could do one without much difficulty.

MHA has a lot of information.

Here's a well illustrated page about Masonry heater construction.

[james]

Re: Wood Burning Furnaces

FB is a member of the MHA, and I have a lot of respect for those guys.

James

[BurntFingers]

Re: Wood Burning Furnaces

We have a Yukon multi-fuel furnace in our house. We put it in when we built the house back in the '70's oil crisis. The air is pre-heated by a hybrid solar heat bank of riverbed gravel in the return path. It has worked well for us ever since. (I hope I am not jinxing it now by bragging) My wife loves the extra heat it gives when it is working just on wood. We have 3 thermostats, 1st stage = solar, 2nd stage if not satisfied the air damper opens and the wood if lighted flames up, if no wood lit up then 3rd stage #2fuel oil burner kicks in. If there is wood loaded and the oil kicks in it will light the wood. -- I understand that there are coal or gas combo's available. Last winter we used 20 gallons of oil and 2 cord of wood all heating season.

[Archena]

Re: Wood Burning Furnaces

I've been drooling over masonry heaters for a long time. They originated in the Netherlands in the Middle Ages (or shortly after, not sure). From what I've read they're fairly complex construction wise. I do know that some folks have actually hired Dutch masons to come over and build for them.

[Archena]

Re: Wood Burning Furnaces

... Last winter we used 20 gallons of oil and 2 cord of wood all heating season.

How does that compare to an ordinary oil furnace's oil usage? Is 20 gallons particularly low? I would think so but I have zero experience with oil furnaces - I've never even seen one - and have nothing to gauge it by.

[BurntFingers]

Re: Wood Burning Furnaces

From what I understand from neighbors that heat with oil. Hundreds of gallons are used in a heating season. The oil tanks are in the 300 gallon range for homes and they get filled regularly. Heating oil in NJ is about the same price as diesel fuel. It is diesel fuel with a red/purple dye in it so people can't use it in their trucks or cars. I would guess it takes over 1000 gallons to heat most homes for the heating season.