modern wood stove efficency

Are new wood stoves more economical on wood then a older airtight such as a vermont castings vigilant from the late seventies or do they consume about the same amount of wood.


c.w n.y

neighbor crows about his charmaster. Same size as my kingswood wood furnace.

But he fires it once every 12 hours, I throw wood in once every 4 or the fire goes out.

Either he uses better wood or I have more air going in with the holes closed.

Can't address their efficiency, but we've had a Phoenix Hearthstone (soapstone) for 13 years and love it; doesn't have a true catalyic converter, but has a series of internal pipes thru which the exhaust gases are drawn.
Phoenix Hearthstone

Or he could have a smaller, tighter house. Or the amount of wood he puts in at one time may be way larger than what you put in every 4 hrs.

could be a lot more variables.

Gene

I've long wanted to get one of those stoves that is a wood-gas furnace. A small lower firebox heats an upper box to well past 450'F (nearly 2000'F) where more wood is. The upper box is pumped down to a low vacuum or something so there is little or no air, hence the wood turns to a burnable gas like propane rather than burning with a yellow flame. The resulting charcoal can be burned again in the lower firebox later (or maybe even bagged and resold to yuppies!)

Yeah my house is a story and a half that dates back to about 1810. His is a double-wide manufactured home he put a basement under.

I have owned several wood stoves over the years including a vermont castings vigilant, a very good stove I might add. The latest stove I am running is a Quadra fire 3100. A smaller fire box than the vigilant, but more efficient. I achieve the same burn time and heat output with about 2/3 the wood. You can actually watch the smoke burn in the fire box, only smoke out the chimney is on start up or reload. Dave

Yes, there is a big difference. They also take some getting used to. Besides being more efficient, the newer EPA woodstoves can be turned down low, and the fire won't choke and soot up anywhere near as bad as the 70s "airtight" stoves. It's one of the few things that the EPA did that caused an improvement. Also caused a big jump in prices.

I used to work for an air-tight stove maker. Thermo-Control. They are still selling stoves but the law now prohibits them from calling them wood stoves. Since they don't meet EPA specs, they are now "wood furnaces."

To increase our woodstove's efficiency (which has its own small cage blower) I use a vertical fan that blows against the stove. I have a magnetic "burn indicator" on the stove pipe and keep it on the low end of the normal operating scale except periodically letting it get hotter. I also brush the stove pipe at least once a month.

.... and thus you have found your answer.

Rod

We had an airtight Elmira Stoveworks with the baffles, etc. to burn the smoke more efficiently. Top of the line with all the "latest" features in its day of the late 80's. We switched to a Blaze King airtight with catalyst in 2001. Our wood use went down by well over 50% for the same amount of heat. Same house, same type of wood, same everything else. So I would say yes, the new stoves are designed better. I would never go to a non-catalyst stove again.

The house I bought had a old stove that would just eat wood. You had to fill it before work and as soon as you got home and on cold nights it would be out at 2 in the morning after only being filled at 9. I replaced it with a hitzer coal/wood furnace box that i burn wood in. it last 12 + hours and I only burn a little over 3 cord for the whole winter. The house is newer construction so that helps. If you want effiecient switzer out of Dundee ny makes a boiler that burns wood. It only needs wood when the water temp gets down and it light off in just minutes. And since it is a boiler design it is efficent. You have to see one to really understand how they work. I believe he takes them to farm show. But from what I have seen the new one are twice what the old ones were and you have better control over the warmth of the house. We burned wood the whole time I was growing up and either it was to hot or to cool in the house.

JD, I have a Thermo control model 400 and dads got the 500, hes had his for 29 years. It needed a set af water coils so he got the stainless steel ones. They are good stoves. On mine I put a fender screw clip on the thermostat damper flap on the air inlet so the flap cant close tight, it allows a little air in so it can burn. Without the gap, the damper would close down tight and than the fire would just smolder and give off hardly any heat.
I think Im gonna take the water tank of of my system thought, because the stove seems to small to heat that much water. Water temp runs 90 deg, or maybe 115 when its really burning.

Yes, the 400s and 500s were our biggest sellers. Made in Cobleskill. I heat my four-story barn and shop with an old 500. My daughter also heats her big farm house with a 500, and my son has a 400. Since it was a local product, they are very common around here. They run pretty efficient when run at full heat, and pretty poor when run low.

Last year, I needed a part, and just for the heck of it I drove down to the old shop in Cobleskill as was surpried to find out they're still making them. I got the parts I wanted cheap (thermo-control door setup). They were down to a two person, part-time operation. Putting tin sheds on the 500 and selling them as outdoor furnaces.

They are good old stoves, but we had to do a lot of repairs. When run hot, the baffles and steel in them warped or burnt out something awful. I rarely see an existing stove that hasn't been reworked and rewelded. 3/16" steel just is not durable enough to sustain the kind of heat those things make, especially at the rear baffle. Mine has 1/4' stainless in it now and it's been fine for 10 years since I fixed it.

My wood furnace in my house is of similar design by made by Meyer Farm Equipment and called the Woodchuck. It also has 3/16" steel but all is firebrick lined. Again, pretty efficient with a hot burn, and not with a low burn. But, I've got lots of wood and a virtually fireproof Canadian chimney. Canadian stovepipe exceeds most USA versions.

Putting a cold air supply on any conventional combustion device will dramatically improve its hea output. (the reason that condensing 90+ % efficient furnaces have them)
Cold air keeps the device from sucking air out of the building into the fire. All new stoves should be equipped to handle cold air introduction. JimN

Not needed and no gain in old houses. New tight houses, yes.

My house was built in 1820. I've tightened it up quite a bit, but still gets all fresh air a fire needs.

An Air tight stove couldnt burn wood at all.