OWB or wood furnace?

[4wydnr]

I'm looking for ideas on what I should use to heat my house next winter. For starters I have a 2 story 1800 sq ft house in the country. I would say insulation is mediocre. I have good access to wood, hard and soft. Last year, for reference , I had a magnum 7500 corn furnace that just didn't cut it, it could barely keep the house at 60. My parents have a similar sized house with a wood furnace that will cook you out, while a friend of mine has a smaller house that you freeze in. I'm not sure if it has to do with the furnace type or insulation?

My parents' burner is an older unit that is very well built and has a draft motor. With a good fire going inside your can place your hand anywhere but the door. They use the wood furnace as the main heat source and burn maybe 2.5 cords/year. My friend has a Daka from menards that has hot spots everywhere and no draft motor, he too uses it as his main heat source and burns in excess of 5 cords/year.

Any thoughts, pro's and cons of each would be greatly appreciated.

 

[benjamin]

The general concensus is that the ultimate system is a gasification boiler with thousands of gallons of pressureized storage, and no doubt it will be extremely easy to operate. Without the storage you will have to load a little more often and possibly have to clean your chimney more often.

Or you could take that $20,000 worth of cash and labor and invest a portion in tightening up the house, especialy since you have a relatively powerful corn burner already installed. Assuming there is no problem with your unit, if your corn burner (@ 78,000 btu/hr) can't keep up, you're going to have a challange keeping any wood burner filled as well.

I would guess that the biggest difference between your friend's and your parents' houses is the air sealing. Insulation is a distant second in priority to sealing the simple air leaks, especially in an older two story house. The chimney effect causes hot air to leak up into the attic, and cold air to be drawn into the loer levels. If you have a full attic, it can be fairly simple to seal the air leaks, if you have a story and a half with knee walls and dormers, good luck.

 

[4wydnr]

I thought the corn burner was working correctly. I could get a nice dancing flame out of it, it just never did a good job of heating the house. Anyhow I sold the corn furnace this spring. Maybe the insulation is worse than I think or the fact that my roommate had a window in his room open most of the year! I think next year I'll definitely check all the windows and storm windows. Along with a couples tubes of the pealable caulk. The house is a true two story and the insulation in the attic is pretty decent. I'm leaning towards the wood furnace because they seem to be more efficient. I think the gassification units would be nice, but at this point in my life I have more time than money.

 

[laynes69]

I'll agree if a 78,000 btu corn burner can't keep up then something is wrong. If your home is an older home it could be balloon framed. Check to see if the interior walls aren't open to the attic. Its amazing what insulation will hide. Fiberglass will just act as an air filter, not an air barrier. I would investigate some for air sealing will go a long way on the comfort of the home, and the heating bills. As far as a wood furnace being efficient, many are far from. I would go with something that incorporates secondary air for burning of the gasses, or a cat. We heat with a Caddy EPA furnace and we dropped 2 cords from our annual usage, from the standard furnace with less than perfect wood. The few furnaces that are efficient are the Caddy(EPA), Blaze King Apex, Energy King 385ek and the Kuuma Fire furnaces. If you buy a standard furnace, you will burn more wood and will get more creosote.

 

[ihookem]

Of all the insulation jobs I've done No one has ever complained about the cost after I called them up to ask if they can tell a difference in the comfort of their house. I always ask a year later and asked how the gas bills are and they are happy. Your house is not insulated properly. Start with the attic. Make sure it has 18" of cellulose blown in or 24" of blown in fiberglass. You need at least R-50. Then go in the basement and foam between the joist. Most companies charge 6-800 bucks. You will notice right away how comfy your house is and will burn less fuel. Caulk everywhere needed, windows ETC.

 

[herbdan]

I went through the same thought process the last few years before deciding. I started out with a well insulated/air tight house so I didn't have to expend $$ on that. I looked really hard at at both an OWB and an indoor gasification unit. There are very few, true and tried energy efficient OWBs. There seems to be more coming on the market each year and hopefully that trend will continue. The thought of an indoor gasification unit was very tempting, but two things convinced me that now is not the time. First reason was the overall cost. For my house and the units I was looking at I figured at the very minimum it would of taken at least 15K to complete the install. The second reason I had for not investing in a gasification unit was the complexity and overall maintenance of the the system. There are probably many here that would argue that point but to my figuring, the pipes, storage, valves, exchangers, etc, all add up to a lot of stuff to get right and keep right. I might attempt it once I'm really retired....

So I ended up with an indoor (basement) would furnace hooked up to my existing duct work, but with a separate blower than my gas furnace. The day to day operation of it is very simple, it is very efficient, and I spent about 6K, including a new SS chimney. Good luck, and hope you get something up and running for next season. In the mean time, happy wood hunting.....

Herbster

 

[Gooserider]

Maybe I missed it, but what is your current heating system? If it is forced air, and cost is a major issue, I'd look hard at one of the high efficiency wood furnaces, in addition to the already mentioned airsealing and insulation advice (which should be first priority) If you have a hydronic (hot water) system I'd go with a gasifier boiler. This would be the lowest cost since you avoid changing heat types, and canuse the existing distribution system....

I wouldn't even consider going near one of the traditional "fire in a box of water" type OWB units.

Gooserider

 

[4wydnr]

The current system is a high efficiency forced air setup on propane. Last summer my dad put in an 18,000 gallon (no typo) propane tank for the farm. So he gets a considerable volume discount. But even with the cheap propane and keeping the house under 65 my heating bill was still around $1200. I wouldn't mind paying the money but the house never felt warm to me, so that is why I'm looking at alternatives.

I had the corn furnace piped in to the existing duct work and the most I could ever get from is was slightly warm air coming out of te vents. I didn't think it should be hot like when the propane furnace kicks on. I thought the idea was that is was a consistent heating source. It didn't really matter if the outside temp wad 15 degrees or 40 degrees it would only ever take the house to 60.

I definitely think my first order of business is to address the insulation and air leaks no matter what. I also realize that a standard wood furnace is not "efficient", my comparison was more in relation to an owb.

I appreciate the thoughts and info.

 

[ken999]

Definitely insulation first. With your current cost of heat ($1200) the payback time on any investment will be relatively slow.

We had some spray foam done in half of the downstairs while we had it ripped apart last summer. It is very nice stuff. We will be doing more of it over time as we work our way through the remodeling process.

If you go the foam route be sure that you have all the outlets, plumbing, extra conduit etc. run FIRST. We added some blanks in the walls in the event that we decide to run more wire down the road. Plan ahead...

We installed a CB E-Classic gasification OWB last year as we were spending $3500 or so in oil PLUS burning 4-5 chord of hardwood through our Pacific Energy Summit insert. Our payback will be in four years if I manage to get all my wood for free. That's very likely as we have 22 acres growing it every day. The E-Classic is far from perfect, but CB is steadily improving things. Econoburn just released a OWB version of their indoor gasification units. They appear to be very nice and I would be looking pretty hard at one if I were to be buying these days. An indoor gasifier installed in an outbuilding is a great way to go as well. I believe you would need to add indoor storage and to get the maximum from these Econoburn units. Our CB has 450 gallons of water in the system which kinda gets around the whole detached storage idea, but likely it is not as efficient as other systems. We have had pretty good luck with ours though. It's fairly convenient only having to load it 2x a day in the middle of winter. Our house has never been warmer and the system allows us to now heat our domestic water with wood, not oil. I'm still lighting it 2x every day for our domestic water. I let it run up to 195 then shut it off. We went the OWB route to get all the mess and fire OUTSIDE, where it belongs..lol...

 

[benjamin]

Now I'm really confused.

Was the $1,200 the price of just the propane? at what price? or was it the combination of corn and propane? $1,200 doesn't seem that bad, there must have been something wrong with the set up of the corn furnace. Was it running all the time and using as much corn as it should?

There are certainly better wood furnaces than others, Menards is not the best place to look but even they can be used efficiently if you're willing to spend a lot more time burning right. Sorry, I can't tell you who makes a good one these days. Almost any wood furnace will be more efficient than almost any OWB, the OWBs are poplular because it's so convienient to dump huge amounts of wood right next to them, and you will need huge amounts of wood in most cases.

You mentioned that your attic insulation is pretty decent, if it's fiberglass it's useless and if it's cellulose it's next to useless. You need to pull it back and seal up all of the cracks and holes and openings from the inside of your thermal envelope to the outside. One great way to do that would be to remove all insulation and have a couple of inches of foam spayed over everything, then add the insulation back in. One cheap way is to rake the insulation down to the level of the cieling joists, add a layer of 6 mil plastic and rake the insulation back over the top, then blow more cellulose so that the plastic is in the inner third of the insulation.

 

[woodsmaster]

Now I'm really confused.

Was the $1,200 the price of just the propane? at what price? or was it the combination of corn and propane? $1,200 doesn't seem that bad, there must have been something wrong with the set up of the corn furnace. Was it running all the time and using as much corn as it should?

There are certainly better wood furnaces than others, Menards is not the best place to look but even they can be used efficiently if you're willing to spend a lot more time burning right. Sorry, I can't tell you who makes a good one these days. Almost any wood furnace will be more efficient than almost any OWB, the OWBs are poplular because it's so convienient to dump huge amounts of wood right next to them, and you will need huge amounts of wood in most cases.

You mentioned that your attic insulation is pretty decent, if it's fiberglass it's useless and if it's cellulose it's next to useless. You need to pull it back and seal up all of the cracks and holes and openings from the inside of your thermal envelope to the outside. One great way to do that would be to remove all insulation and have a couple of inches of foam spayed over everything, then add the insulation back in. One cheap way is to rake the insulation down to the level of the cieling joists, add a layer of 6 mil plastic and rake the insulation back over the top, then blow more cellulose so that the plastic is in the inner third of the insulation.

I would not put plastic on a cieling you could cause a serious mold problem. moisture should travel threw the cieling and vent out the attick and plastic makes that impossible. Yes seal any openings with foam then
add cellulose or blown fiberglass to an R-60 . Make sure not to block air from eaves by adding air chuts

 

[benjamin]

Moisture movement is mostly in the air that is moving, not vapor diffusion. The example they use is a sheet of drywall which is fairly permeable, will have a cup or so of water diffuse through it over a winter, while a one inch square hole will have 30 cups move though. I'm probably butchering the example but you get the idea.

Aside from basements, I've only seen mold problems caused by a vapor barrier when it is installed on the underside of the rafters, the rafters are insulated with fiberglass allowing too much air movement and obviously there is no vent in the rafter space. This causes the air that leaks though the bottom edge of the drywall and up from below to drop moisture on the bottom of the roof boards faster than the moisture can travel through layers of shingles, and make a mess of mold and rot.

It's fairly common to install vinyl siding on old houses over 1" or even 1/2" of foam sheating, either foil face or pink stuff, which breaks all of the rules of vapor barrier location, but I've never it cause a problem. If you have the plastic on the bottom third of the attic insulation you won't have a problem.