Central heating using wood?

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Still musing about the kitchen/great room extension. We have considered making the space of our old kitchen into a food storage, canning/beer making area (our addition would start with a new kitchen). We would also have space for a furnace in the old kitchen. Out here, most everything is electric or natural gas powered (LP for us since we're no where near a gas line, though.)

Is there such a thing as a wood-fired central heating source? I see those ads in CS for those plants that stand alone outside. Seems logistically tricky.

The idea of having heat magically come out of vents in the floor is starting to be somewhat appealing. When I get a little older, it will seem even more so, but I'm always concerned about the supply chain and curious about wood heat instead of gas or electric. Of course, we'd have our woodstove as backup so may that's not really any issue, I guess.

Anyway, any ideas? Thanks.

-- Anonymous, March 22, 2002

Answers

Sheepish,

We designed a wood heat central heat system for a mobile home by building a small cinderblock building with sand floor and a fan connection to the ductwork of the mobile home. Load the woodking stove twice a day to provide heat. Since we already had the wood heater, costs were less than $600 and it held up longer than those self contained outdoor units advertised in Countryside.

-- Anonymous, March 22, 2002


Sheepish, as you think about getting older, do you see yourself still desiring and having the physical ability to carry and load wood enough to fuel one of these? Are you against using a fossil fuel?

If you want magical heat, you might consider the LP fireplaces or wallmounted units. I know that Natural Gas ones sell for as little as $129 here for 10,000 BTU's. They have piezo ignition and no electric. The fireplace style (and also the fireplace inserts) can have an optional blower that increases circulation should you need that. I used an insert at my Dad's house and it was very efficient and had infinite settings for blower time and temperature, etc. We bought a stand alone unvented one (20,000)for the new rooms upstairs. We got it here at the end of heating season and got an incredible deal- regularly $650, we paid $360. You might get better prices where you live. Its not hooked up yet-still doing the drywall, so I can't tell you how well that one works. I LOVE the wall-mounted unit I have in my office, which is the above-described $129 version. Easy to mount and maintain and instant heat when we want it. It actually can keep the chill off that entire side of the house. We count on it for those times there is no electric out here, which isn't often, but enough to have us planning for it- which is why we bought the second one for the upper floors.

-- Anonymous, March 22, 2002


You could also put a fireplace insert in and pipe the heat diverters into your central ductwork.

-- Anonymous, March 22, 2002

Hmmm. We don't have any ductwork as of yet. But some good considerations. Thanks.

Yeah, getting the wood in might become challenging. I remember my grandfather (in his 80's) dealing with his old Ashley wood heater. He loved the heat (HOT) of his stove, but it was getting to be a problem to get the wood in.

I would prefer not to use fossil fuels, but I would consider using them (since I drive a car daily, I guess I'd be a hypocrite if I didn't!). Mostly I'm just trying to live as lightly on the planet as possible. I don't always do such a good job as I'd like, though.

My goal would be to have a superinsulated house (we're almost there) and to be able to adjust a thermostat when I get home and get "instant" heat in all the rooms. Right now, I have choices: I can turn wall-mounted electric heaters on in all the rooms (the original house design + "heatolater" fireplace) or build a fire in our Lopi insert and/or do the wall heater thing. We almost always build a fire and wait for the heat...sometimes takes a long time to heat the whole house. If we're in and out during the week, seems like the house never really gets warmed up. Plus the space heating in various rooms seems to create drafts of cold and warm areas.

Mr. S. had told me that there were hybrid types of heaters where you could burn wood/coal/gas as a source and pipe heat into your ductwork. I haven't considered this in years and wondered if it's still an option.

Thanks for your answers!!

-- Anonymous, March 22, 2002


We have an outdoor boiler. Generally I like it because of the convenience factor. By that I mean thermostatically controlled heat and no wood mess in the house. The down side is ours uses alot more wood than I'd like.

I may be wrong about this because I haven't really kept up with whats been going on in the wood heat world but I'm not aware of any wood stove that can be thermostatically controlled by a thermostat on the wall like the more conventional petrofuelled heating systems.

On the other hand if you use water as a heat exchange medium that opens the way to genuine thermostatically controlled heat.

-- Anonymous, March 23, 2002



Hey sheepish, Mr. S knows what he's talking about. Almost all of the big farmhouses around these parts have a propane furnace with a wood add-on. I'm pretty sure that is how my uncles heat their homes. My great grandpa's place had a wood burning furnace in the basement. Do you have a basement or what around here is called a cellar? I've only known these furnaces to be placed in basements with the ductwork going wherever. But then again, I don't know of any house around here without a basement.

Come to think of it, my SIL in Indiana has a wood furnace in the attached garage and the heat is ducted into the house.

-- Anonymous, March 23, 2002


Thanks for asking this sheepish,we are in the same dilemna.With 54 acres of wood it seems obvious to use it.We are pricing the central boilers from cs,only here in canada and would like to have radiant floor heating,no blowy stuff for folks with allergies,but its looking far to costly.Can't you get a wood/electric,wood/gas or wood /propane furnace there?Thats our next option.We are building 680 ft in and so far it looks like hydro is going to be close to 10 thousand,any suggestions windmill not an option.Apparently the wind maps say our winds don't reach 15 km on a steady basis,and it would have to be one honkin big windmill to get over the trees anyway.

-- Anonymous, March 23, 2002

Sheepish, we have always used fuel oil forced air furnaces in all the big ol' farmhouses we have had over the years, we use fuel oil (diesel) in our semi truck, so why not use it to heat our house? Fuel oil gives the highest heat exchange per unit of fuel to BTU ratio there is, so it is the most cost effective, and the furnaces last a very long time with minimal maintainence required every three or four years (change the fuel filter and the nozzle like fuel injector, oil the blower motor).

Diesel fuel rates are always cheap in midsummer, so having an underground tank large enough to hold a years worth of fuel is the wisest choice for cheapest economy, some summers it is 69 cents a gallon!!! We have a 500 gallon underground tank and that lasts 3/4 of the year for us.

It is a very clean heat, no smell or fumes when the furnace is properly adjusted and burning properly, puts out plenty of heat in a hurry too!

We have always lived beyond the reach of natural gas, and propane costs way too much for primary heat use, although we do have propane for the stove and for the back-up gas log heaters which work without electricity.

We both have allergies that preclude the use of any type of wood, coal, or corn burning stove heat, even the outside boilers put out too much stink too close that causes very bad allergic reactions, like instant migraine headaches for me, bad nasal allergies in my DH, and aggravates his latent asthma left over from an asthmatic childhood many, many years ago.

A good quality fuel oil furnace costs about 2500 installed, add a 1000 or 1500 for all ductwork installed, as well as the required fuel tank.

-- Anonymous, March 23, 2002


John...could you describe your "wood boiler" system a little?? Harry and I would like to go to a set up that's a little more convenient, but still burn wood as we have 95 acres of it! We would like to keep our wood cookstove (til we're really old if possible!!), but would also like to wake up in the morning to at least 60 degrees!! Right now we use about 8 cord of wood a year with an antique cookstove. Do ya think a wood boiler would help??

-- Anonymous, March 23, 2002

Marcia: Our boiler is a Johnson Energy Converter, so called because its designed as a downdraft gassifier. The reason I bought it is because they said it used less wood than other brands---NOT!!!. The first coupla years we used ALOT of wood but thats partly due to an installation screw-up---my fault. The underground lines weren't insulated well enuf so I lost alot of heat before it got to the house. (VERY important to well insulate the underground lines sez the voice of experience!!) This year I rerouted the lines and now they're running directly into the basement. I also REALLY shortened and insulated the underground portion of the lines. Its alot better than it was but I can't say I'm thrilled with the wood consumption yet. I figure I'll use about ten cords this year.

Another benefit to the outdoor boiler system is preheating the domestic hot water. I figure at least a third of our electrical use goes to making hot water.

This summer, if all goes well, we're having a new roof put on the house so while we're at it I'm gonna insulate the new attic with 18" of fiberglass. That'll give me an R rating of about 63 so its expected to cut wood usage down substantially.

The house is reasonably well insulated now with an average of maybe 7- 8" of fiberglass. Its approx. 1500 square feet plus a full basement. We heat about 2/3 of the basement to about 55 degrees with intentional heat loss from the semi-insulated lines that are now inside the basement. We have a radiant floor in the basement too but we rarely run it---only when we have over-night company. The upstairs is warm---70 degrees plus, depending on whos operating the thermostat, me(70 degrees) or Chris(80+ degrees).

I generally load the boiler three times a day because its convenient but only two are actually necessary.

Before you bite the bullet and buy one, look around to see whats available. When you've narrowed down your choices, ask for references and actually talk to someone who has the unit(s) you're interested in.

Keep in mind that you're gonna be totally screwed if you lose electrical service. The system will require at least one circulating pump(very small electrical usage) and possibly a combustion blower, depending on the type of boiler. So if you lose power for any length of time it'll be necessary to drain the boiler and lines to prevent freeze-up.

Another thing to consider is the size of wood you'll be chucking into the boiler. Some of the boilers I've seen have BIG fireboxes and will accomodate really big pieces of wood. That sounds all fine and good unless you have to lift this big chunk and load it into the boiler.

We were kinda fortunate in that ours was "new-construction" so in anticipation of Y2K we had a back-up electrical system set-up with the eventual intention of having PV and/or wind energy too.

I figured this was gonna be a one time deal and I've always been interested in the energy thing so I built in alot of flexibility for experimentation. I've got an 800 gallon insulated concrete water tank in the basement that'll be used as a heat storage tank. That'll be to store heat from the boiler as well as a fairly large solar hot water system that's going in this summer. I figure the solar system will supplement the boiler in the winter and keep the house warm during the spring and fall without the boiler, also reducing wood consumption.

One thing I've been toying with is the idea of cogeneration. What cogeneration means is you produce heat AND electricity. In this case I'm thinking about a marine diesel gen-set. You capture heat from the cooling water and the exhaust while you're making electricity.

Around here we have whats called net-metering. That means the electric company will pay us the same rate we pay them for electricity up to 20kw. With a 20kw set-up we'd produce about $1.30 worth of electricity/hr at $.065/kwh and about 120,000btus of waste heat. I figure I can store close to 1,000,000 btus of heat in the storage tank so to produce that much heat I'd have to run the gen-set about 8.3 hrs. To do that I'd generate $10.79 worth of electricity.

You can run a diesel on heating oil so at a cost of $.70/gallon (summer prices) I'd actually be making approx. $.60/hr on electricity. It doesn't sound like much but considering that I'd be heating the house, providing my own electricity plus generating a surplus for less than nothing it looks pretty good. The gen set I saw was rated to use 1.1 gallon/hr. according to manufacturers specs. I think I'd also be able to blend the diesel oil with free-for-the- taking drain oil. If it was a 50% blend that's reduces the actual cost of the fuel to $.35/gallon, thus increasing the bottom line to $.95/hr. "profit".

More than you wanted to know probably but there it is. Hope that helps.

-- Anonymous, March 24, 2002



If consideration of air quality is a factor I don't believe the big outdoor wood fired boilers are the way to go. I have lived next door to three of them and they were terrible spewers of foul odors. In additon they were wood hogs compared to freestanding wood stoves. Most modern well engineered stoves utilize high firebox temperatures to achieve a clean burn. By their very design, the big boilers surround the firebox with a large jacket of comparatively cool water. I have yet to see one in operation in Washington or Oregon and I believe the reason is they cannot pass the clean air requirements out here.

Over the years we've had most every kind of heat imaginable and for the last two years, up until a month ago, we had forced air heat and I hated it. The only way to get heat was to create a draft. Whether elec,gas or wood,fan induced heat was always inferior to radiant heat, in my opinion. Someone mentioned small gas units that can be mounted directly on the wall. I would add the type that use radiant ceramic plaques are much better that the blue flame type. The heat is sent into the room without the aid of fans, in fact it feels a lot like radiant heat from a wook stove.

I envy your r-values sheepish. We just bought a super good cents home and have discovered that it doesn't take much to qualify as a super good cents home. Our walls actually have an r value of 11. Just goes to show after all our research we did'nt go far enough.

If spring would arrive in the physical world as well as on the calendar, we could forget about all this talk. jz

-- Anonymous, March 27, 2002


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