Types of Wood Furnaces

justanothercub said:

Is there a thread that talks about different makes and models of Wood Furnaces that people have used or are using? I scrolled through 15 pages here in the Central Heating section and didnt find anything. Laynes69 and I have talked about a couple models, but I was wondering if there are others out there that would weigh in with the experience.

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Go to lamppakuuma.com and check theirs out. Put one in my house last fall and ordered another for my shop! Unbelievable furnace.

justanothercub said:

The kuuma 200 according to what they claim it will heat ( a 3,000sqf home ) and that would suffice. But they say It is used basically as an add-on to your existing oil, gas, or electric furnace. Not sure why they say that.

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I doesn't seem set up to have an plenum on top, but rather looks like it is designed to have a duct connect to an existing plenum (i.e., on another type of furnace. There doesn't seem like there is a huge difference in price between the 200 and 100. It is a bit confusing that the 100 is bigger than the 200 though

It has an 8" take off collar on the top. You would put and 8" pipe to connect with your existing duct work or the bonnet of your other furnace (gas, oil, electric). The Kuuma Vapor-Fire 200 model is designed so when there is really cold weather you can have your other furnace fan come on to push the heat quicker. In normal weather the 465 cfm fan will almost always suffice without having the other blower as a helper, because it's steady even heat hour after hour. The Kuuma Vapor-Fire 100 model has a larger blower which means you don't need another existing fan ever to come on.

justanothercub said:

Is there a thread that talks about different makes and models of Wood Furnaces that people have used or are using? I scrolled through 15 pages here in the Central Heating section and didnt find anything. Laynes69 and I have talked about a couple models, but I was wondering if there are others out there that would weigh in with the experience.

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Is there a reason why you specified wood furnace as opposed to wood boiler? I ask because my first inquiries, five years ago, were about furnaces when what I really (really) needed was a boiler.

justanothercub said:

Thats a good question, maybe I need a boiler with a forced air add on. I'm a radiator hot water boiler guy. I built our current homes heating system and it works like a charm for our house, I always thought that if you have a forced air system a Furnace was the way to go. But if im wrong by all means let me know. Thats why I am here ( to learn ).

What I do know is I dont have the energy or the money to pipe our new house for ( baseboards or radiators ).

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Used Cast iron rads are what I eventually would like to have. Currently I am using a water to air HX in the plenum of my backup oil furnace. Radiant pex lines in a ceiling or walls or floor are another good option.

Most furnaces are "Add-On".. They are intended to Add-on to an existing HVAC (Hot air) or Radiator (Bioler) system. Its not that they should be used in conjunction, but they are used alone..

My pellet furnace was an Add-on.... But I just ducted it, into my existing HVAC.

justanothercub said:

So basically as long as the btu's are enough it doesn't matter if the manufacturer calls it a "add on"?

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You cant have a solid fuel burning device as a Primary heat source, for insurance reasons (if you ever sell the house, etc)....

So they are "Add on" or can be used as a stand alone unit, but you will need an entire separate Duct system (expensive$). So most forced hot air pellet/wood furnaces are considered Add-on.

An add-on shares the central blower on the main furnace that it's tied to. This installation is called series, for the wood furnace runs in series with the central furnace. On a parallel install, both furnaces have thier own blowers. The ductwork is then retrofitted with backdraft dampers so either unit won't back-feed into another. Just like series installs, parallel shares the ductwork with the main furnace. On a stand-alone setup that's it. When installing a woodfurnace, you need to follow proper clearances with your ductwork, and maintain specific static pressures specified in the installation manual. Most stand-alone furnaces have a large blower with a large plenum opening. Wood furnaces are now being made where they have more versatility in the field, components like limit/controls, fans and other parts coming optional as well as installs that can take either left or right side. When looking for a more efficient furnace those that are EPA certified, or B415 approved will burn cleaner and use less wood. There's strict requirements to qualify for either that must be tested.

Boilers heat water rather than air. With water, there is a multitude of options for emitters. Rads, baseboard, staple-up in walls, ceiling or floors or (less desirable like I have) water to air heat exchanger. There are also lots of choice in the wood boilers as this forum exemplifies. It is easy to heat your domestic hot water with a boiler setup. Storage is an option to increase efficiency and reduce firing times. Different fuels are possible like wood, & biofuels like straw, switchgrass and miscanthus, corn & pellets of wood or biofuel origins. Using a primary/secondary design for the plumbing allows for easy expansion of the system for auxiliary buildings (like shops, barns) or applications like hot-tubs/pools. As I indicated above I originally thought a furnace like the Caddy was the correct choice. Fortunately I found this forum before I pulled the trigger.

Mushroom Man said:

Boilers heat water rather than air. With water, there is a multitude of options for emitters. Rads, baseboard, staple-up in walls, ceiling or floors or (less desirable like I have) water to air heat exchanger. There are also lots of choice in the wood boilers as this forum exemplifies. It is easy to heat your domestic hot water with a boiler setup. Storage is an option to increase efficiency and reduce firing times. Different fuels are possible like wood, & biofuels like straw, switchgrass and miscanthus, corn & pellets of wood or biofuel origins. Using a primary/secondary design for the plumbing allows for easy expansion of the system for auxiliary buildings (like shops, barns) or applications like hot-tubs/pools. As I indicated above I originally thought a furnace like the Caddy was the correct choice. Fortunately I found this forum before I pulled the trigger.

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Interfacing with solar is possible to reduce fuel consumption. With a boiler it is also possible to locate the boiler in such locations as to reduce fuel handling. For example, in my case I located the boiler in an attached garage where I can deliver the fuel stacked on pallets and I don't need to go outside to fuel the boiler. The radiant heat off the boiler and piping is kept inside the house envelope. Location of the boiler is important and offers greater flexibility than a furnace in the basement.

One advantage is the ability to add more storage, so you don't have to be burning all the time. You can also use a water to water heat exchanger to heat your domestic hot water, as well as heat your home with your boiler. If you upgrade to panel radiators they are supposed to put out a very comfortable heat. Most of the gasifiers currently available are boilers so you have a greater choice of models with various features. like lambda sensors, and various costs. I chose mine because it was UL listed, which my insurer and local Building Department required and Tarm has a long track record selling boilers. That is not to put the knock on any other gasifier manufacturer. Its just nice to have options. I used to have a spreadsheet on all the USA available models I could have forwarded you, but lost it with a computer crash.

"WoodNotOil" maintains a site listing and reviewing many models. Here is a link: http://www.woodnotoil.com

Good luck.

Mike

justanothercub said:

What are the benefits of the boiler with a water to air heat exchanger? I had all but made up my mind about the Caddy furnace, then I started thinking that most likley down the road I will want to put radiators in the house, because I prefer that heat.

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Boiler will allow you to go to more/all radiant in the future. You will be able to add more storage as/when you see fit & take a break from babysitting a fire. Boiler will allow you to heat your DHW as well as add other loads like a pool/hot tub/garage/shop in future. Please note that with the potential of all these possible extra loads selecting a boiler with an adequate fire rate is critical as well as adding adequate storage or you will be back to babysitting a fire. Generally a boiler is more flexible in what it can heat via a heat exchanger as compared to a furnace that is pretty much limited to hot air. Boiler with a water to air exchanger in the plenum should provide a lower temp air than air exposed to the side of a firebox & if so will not dry out your structure as much as high temp air. As far as eff. water is a better medium than air for energy storage, transmission & release so on the eff. side a boiler wins simply due to the water. I have not seen a wood furnace up here in a long while, have they worked on the issue of excess heat discoloring/drying out the floor joist above in the typical basement install?

One thing to be mentioned is, one of the common reasons you see furnace/ducting, is that it allows you to run AC through the same ducts. Canuck described the benefits of a boiler nicely.