New house, Old furnace, New Plan.

[Smoke Signals]

So my wife and I bought a new (to us) house and it came with an old Johnson Energy Systems wood eating smoke breathing dragon of a furnace. What a deal rite? Well sort of. Since I grew up burning wood and was, at the old house in my Some what reformed smoke dragon of a Sierra I had a nice stock pile of cut, stacked and dry hard maple and oak. So far so good but her is the rub. This thing is a %$#@! It's eating my beautiful pile of wood like a kid eats candy! In one way I can't complain, we are in the country and we are on LP but have used hardly any thanks to this beast so it's saving us big $$$. It has taken a little getting used to but thanks the things I have learned here I have gotten on to firing this monster, I mean this thing has a fire box like a steam locomotive! I swept the stack (it was bad) and over the last month or so it still looks pretty good considering but something has to give!

So here's the plan, please let me know what you think. I really would like to install a Kumma but the budget will not allow that rite now so I'm thinking that a Dorlet Tundra will be purchased and installed this summer along with a chimney liner. We will burn it for a few years until the bank account will allow the purchase of a Kumma. At that point my brother will inherit the tundra and we will sell his Fire Chief to recover some of the cost of the Kumma and the world will once more be at peace! So what a ya think? feed back, pointers, criticism, considerations. It's all welcome. Let me have it!

 

[brenndatomu]

Sounds like a good plan.

Reformed smoke dragon Sierra? How'd ya do that? I know someone that has one and it needs the whip cracked on it a bit!
Never mind, I just seen your link...

 

[Smoke Signals]

Yeah, I should update that thread. It works but could be better. Needs more pre-heater.

 

[brenndatomu]

Yeah, I should update that thread

I see that...
More preheat and "insulated" firebox to keep temps up. Firebrick, and then ceramic insulation board up top. The heat is then transferred via the top plate being hotter than ever because of the superheated exhaust passing by on the way out. The added mass adds extended heat time when the fire is burning out too. 'Course, it delays heat at the beginning too, so maybe it's a wash.
A ton of time you have in the ole girl there, nice job on 'er too!

 

[laynes69]

What's your square footage, insulation and how tight is your home? Those old furnaces will heat, but like you say they have an appetite.

 

[Smoke Signals]

What's your square footage, insulation and how tight is your home? Those old furnaces will heat, but like you say they have an appetite.

The house was built in 1930 and is a 1500 sq/ft cape cod with another 800 to 1000 sq/ft unfinished basement. I am unsure about the insulation at this point but it seems to be ok. The windows have been replaced and are pretty tight. The house sits on a hill side with a fair amount of southern exposure, I have noticed a small amount of solar gain on moderate sunny days. We are pretty we protected form the north by the rest of the hill and trees and some what protected form the east and west by trees.

To give you an idea of the current situation, on a ~30 deg day I can start a good hot fire when I get up around 4 am and the house is about ~67 deg. this will raise the temp to 70 or 71 and then if no wood is added slowly coast back town to around 67 or 68 by the time I get home around 7 pm when it's time for another fire.

 

[laynes69]

It sounds like the Tundra would be a good match from what your saying.

 

[Smoke Signals]

I see the Tundra is listed as having a 22 5/8 inch deep fire box. If I cut my wood 20" will it fit ok or should I cut it a little shorter?

 

[BoiledOver]

Are the Kuuma and Tundra equal in efficiency? If there is a difference, would a loan be in order to upgrade and still have the return on investment? Interest on a loan for a wood burner is way cheaper than heating with propane.

 

[brenndatomu]

I see the Tundra is listed as having a 22 5/8 inch deep fire box. If I cut my wood 20" will it fit ok or should I cut it a little shorter?

20" should be fine

 

[brenndatomu]

Are the Kuuma and Tundra equal in efficiency? If there is a difference, would a loan be in order to upgrade and still have the return on investment? Interest on a loan for a wood burner is way cheaper than heating with propane.

The Kuuma is gonna be a bit more efficient if for no other reason than it has a computer constantly monitoring and adjusting to optimize the fire. Is it worth that much more...only you can decide that. There is a pretty good gap between the price of those two units

 

[Smoke Signals]

Are the Kuuma and Tundra equal in efficiency? If there is a difference, would a loan be in order to upgrade and still have the return on investment? Interest on a loan for a wood burner is way cheaper than heating with propane.

This is a great consideration that I had not thought of and it brings about some questions on relating efficiency to actual cords of wood. One way or the other I'm going to be burning wood but the real question here is how much rite? The less wood I have to processes the better in my book but how do we measure the ROI in this situation? No matter if I go with the Kumma or the Tundra the result will be less wood burned over what I am doing now but how much? So the Kumma has an advertised efficiency of 84.4% and the Tundra weighs in at 76%. If we subtract 84.4 from 76 we come up with 8.4%. Taking and educated guess I going to say I will burn 4 cords with the tundra so if I take 4 cords times .084 or 8.4% I come up with .336 of a cord. So ruffly 1/3 of a cord. Hows this look so far? Am I figuring correctly?

Lets do a study of the economics of cord wood. The price difference between the two is about 30 truck loads of wood if they were say $100 a load (I don't buy wood, is this about rite?). As far as I can tell a truck load thrown on is real close to a face cord. So lets say the price difference is about 15 cords of wood. So burning 1/3 of a cord less per year is equal to 1 cord every three years. 1 cord every three years times 15 cords is an ROI of 45 years on the price difference. I my thinking correctly here?

Every one please mull this over, see if I am figuring correctly and let me know.

 

[brenndatomu]

This is a great consideration that I had not thought of and it brings about some questions on relating efficiency to actual cords of wood. One way or the other I'm going to be burning wood but the real question here is how much rite? The less wood I have to processes the better in my book but how do we measure the ROI in this situation? No matter if I go with the Kumma or the Tundra the result will be less wood burned over what I am doing now but how much? So the Kumma has an advertised efficiency of 84.4% and the Tundra weighs in at 76%. If we subtract 84.4 from 76 we come up with 8.4%. Taking and educated guess I going to say I will burn 4 cords with the tundra so if I take 4 cords times .084 or 8.4% I come up with .336 of a cord. So ruffly 1/3 of a cord. Hows this look so far? Am I figuring correctly?

Lets do a study of the economics of cord wood. The price difference between the two is about 30 truck loads of wood if they were say $100 a load (I don't buy wood, is this about rite?). As far as I can tell a truck load thrown on is real close to a face cord. So lets say the price difference is about 15 cords of wood. So burning 1/3 of a cord less per year is equal to 1 cord every three years. 1 cord every three years times 15 cords is an ROI of 45 years on the price difference. I my thinking correctly here?

Every one please mull this over, see if I am figuring correctly and let me know.

Well, without actually double checking the math, sounds about right if you are looking at the $ angle solely.
Don't forget the convenience factor and/or longevity. Convenience plays big with the women folk. Anybody can run a Kuuma. Also, never hafta worry about cleaning your chimney in the middle of the winter with the Kuuma. Built to last a looong time too.
Tundra...I dunno, 10-15 year lifespan?

 

[Smoke Signals]

Well, without actually double checking the math, sounds about right if you are looking at the $ angle solely.
Don't forget the convenience factor and/or longevity. Convenience plays big with the women folk. Anybody can run a Kuuma. Also, never hafta worry about cleaning your chimney in the middle of the winter with the Kuuma. Built to last a looong time too.
Tundra...I dunno, 10-15 year lifespan?

Another very good point. Form what I have seen there is a lot to be said for the quality of the Kumma plus it's made i the US and I'm definitely not one to go for the lowest bidder by default. I will pay more for a quality product (if I am in a position to). So I guess this leads to the question of how do you quantify quality? As I laid out in my original post I'm sold on the Kumma and given our current situation (new house and have not sold the old house yet) I'm not in a position to barrow money for the Kumma. But still I would find great interest in a discussion on how to quantify or asses some measure value in terms of quality. Obviously from the manufactures end a price can be put on quality but what about from a consumers point of view? How do we put a price on quality?

 

[JRHAWK9]

One other thing to consider is the Kuuma doesn't need a roaring fire to get heat, therefore it's heating curve is much flatter. It may not put out the max BTU's some other furnaces will during their 2 hour window of max BTU's, but it's putting out more even heat over that burn cycle.

The Kuuma has a computer on it which allows you to control how much heat output you want, from low to high. It has a variable potentiometer; meaning you have more than just three settings to control how much heat you want from it. It's marked low, medium and high, but you are not limited to just those three settings. The computer uses a thermocouple to determine current heat output and automatically adjusts the damper (which is also controller by the computer) for whatever rate of burn you have it set at. The hotter you have it set the more air it allows in through the damper and the more heat you will get. The draft is auto regulated by using a barometric damper which is set at 0.06" W.C. There is a two speed fan, which is controlled by an included wall mounted thermostat. When the thermostat calls for heat, the blower system automatically kicks on high. When the temperature is satisfied and the thermostat "kicks off", the blower system switches back to low where it stays until the thermostat calls for heat again. All this means you can fill it full and not worry about adjusting anything but a little dial to control the heat output you want. The burn times are dependent on what heat output setting you have the computer set as well as how much wood you put in the firebox. More wood + low setting = longest burn times. It will still be possible to overheat the house during the shoulder seasons when it's not as cold, but you can help control that by the type & quantity of wood you use during the shoulder seasons. Anything that burns hot and quick would probably be your best bet to take the chill out on those somewhat warmer days.

 

[laynes69]

I will honestly tell you both furnace's compare with efficiency. Your not going to burn a noticible difference of wood between the two. The Kuuma has the advantage with the computer control, but the same results can happen with a Tundra. Neither require a blazing hot fire, both have similar flue temperatures while operating and both utilize secondary combustion and both can be controlled with a thermostat. While the Kuuma is a higher quality furnace, it should be because your comparing a 2000 dollar furnace to a 4500 dollar furnace. As far as I'm concerned, the Tundra is one of the best furnaces to hit the market dollar wise. A large 4 speed blower, secondary heat exchanger, a fully lined firebox with preheated secondary air and a large glass viewing window make it a very nice furnace. If you want something higher quality that's easier to run, thend buy the Kuuma.

 

[brenndatomu]

If you want something higher quality that's easier to run, thend buy the Kuuma.

Or you could meet in the middle, get a Caddy...

One other thing to consider is the Kuuma doesn't need a roaring fire to get heat, therefore it's heating curve is much flatter. It may not put out the max BTU's some other furnaces will during their 2 hour window of max BTU's, but it's putting out more even heat over that burn cycle.

Hey JR, whats the upper part of the Kuuma firebox look like? I've seen pics of the lower part. It was being discussed recently on one of these forums about the different types of modern clean burn wood heaters out there. I said there is 3 types.
1 "tube type" where secondary air is brought in above the fire.
2 gasifiers where hot air is injected at a nozzle that the smoke/wood gas has to pass through into a secondary burn chamber
3 one with a "cat". Mainly stoves as far as I know

Not sure where exactly the Kuuma falls in there. I have heard the Kuumas being referred to as the only gassifying forced air wood furnace, but I don't know?

 

[JRHAWK9]

PM sent. I will attach this photo I took this fall about 1.5 hours into a burn cycle with the computer set to the lowest setting. It's definitely not as cool as those of you who have windowed doors. It's very hard to capture the "gassification" burn, because as soon as you open the door it disrupts it. I have singed my hair a few times when opening the door in the middle of the burn (to admire the gassification taking place so I positioned my head near the opening) when the burning gases rushed out for a split second.....lol Anyway, the photo below shows the slow burn and I happened to capture just a little bit of the blue flames from the burning gases. I didn't think I got any of them as they disappear so fast after the door opens, until I checked the photo. The blue flames, from the burning gases usually always take place at the front top of the burning chamber. This is where the hot air must get injected. Judging by what I see at times, it's basically like a big ball of blue flames in that area.

 

[STIHLY DAN]

Or you could meet in the middle, get a Caddy...

Hey JR, whats the upper part of the Kuuma firebox look like? I've seen pics of the lower part. It was being discussed recently on one of these forums about the different types of modern clean burn wood heaters out there. I said there is 3 types.
1 "tube type" where secondary air is brought in above the fire.
2 gasifiers where hot air is injected at a nozzle that the smoke/wood gas has to pass through into a secondary burn chamber
3 one with a "cat". Mainly stoves as far as I know

Not sure where exactly the Kuuma falls in there. I have heard the Kuumas being referred to as the only gassifying forced air wood furnace, but I don't know?

Its a combo of 1 and 2. at the front where the entrance to the secondary is, there is 2 riffled pipes. like cutting 4 inches off the barrel of a gun. so the natural draft with the damper closed pulls preheated air and shoots it in a swirling manner right at the choke point of the secondary heat exchanger. most of the gasification is in the secondary compartment that cant be seen.

 

[STIHLY DAN]

Another very good point. Form what I have seen there is a lot to be said for the quality of the Kumma plus it's made i the US and I'm definitely not one to go for the lowest bidder by default. I will pay more for a quality product (if I am in a position to). So I guess this leads to the question of how do you quantify quality? As I laid out in my original post I'm sold on the Kumma and given our current situation (new house and have not sold the old house yet) I'm not in a position to barrow money for the Kumma. But still I would find great interest in a discussion on how to quantify or asses some measure value in terms of quality. Obviously from the manufactures end a price can be put on quality but what about from a consumers point of view? How do we put a price on quality?

I bet it costs kuuma more money paying for their steel in each unit than it would cost to buy a complete tundra at the store. What does that tell you. Also not trying to bash a product, but we are comparing them. I would NEVER buy from a company that I knew, knew that they were selling units that could kill your whole family, then not take them off the shelf till they fixed the problem. It really bothers me that people recommend these units after what happened, just because there cheap.

 

[brenndatomu]

I bet it costs kuuma more money paying for their steel in each unit than it would cost to buy a complete tundra at the store.

That's probably true.
I gotta say, I was surprised to see the weight on the Tundra is listed as 590 lbs. My Yukon Big Jack was 595 and built like a tank! Heavy 10 gauge metal, lots of heavy firebrick, and 2 really heavy grates. I guess the Tundra gets it's weight just because there is a lot going on there, lots of metal passage ways and chambers and whatnot. On the other hand the Yukon is pretty simple, HD firebox, with what is basically a HD barrel welded to it.

 

[JRHAWK9]

I would NEVER buy from a company that I knew, knew that they were selling units that could kill your whole family, then not take them off the shelf till they fixed the problem. It really bothers me that people recommend these units after what happened, just because they're cheap.

What happened?

 

[STIHLY DAN]

What happened?

Their ash pan was in the supply air plenum. not sealed into the fire box. So all the carbon monoxide from smoldering ash's was going right into the room air. Also all the ash dust throughout the ductwork. They were notified, and while they were engineering a fix they just kept on selling them. Then there is the question of how many of them are out there that did not get the retrofit fix.

 

[brenndatomu]

Their ash pan was in the supply air plenum. not sealed into the fire box

It wasn't exactly in the supply plenum. The ash pan drawer just wasn't sealed completely airtight from the blower air stream. Ash pans are not sealed on many free standing stoves, pretty common, I guess the blower was causing enough turbulence to stir things up and cause problems on the Tundra though.
I thought they halted sales until the fix was available? And from what I understand all registered owners were contacted and even a lot of unregistered owners were tracked down.

 

[laynes69]

It really bothers me that people recommend these units after what happened, just because there cheap.

I'm fortunate in the fact my wife and I make a good living, and I've been in the opposite situation. Our economy is not well, and many people can't afford to heat their homes on their wages. It's easy to say buy the best, but for many even a 1000 dollar furnace is too much. Many can't do financing either for one reason or another.

SBI produces thousands of stoves and furnaces every year. With the volume of business they do, they don't pay what others pay for their supplies. If Kuuma produced the numbers others produced, I'm sure their prices would be lower.

As far as a Tundra killing you, the company wouldn't do something like that deliberately. It was unfortuate, but they took care of the problems. No company would stay in business otherwise.