I am considering switching our heating source to an outdoor wood burner. I live in Michigan, so the winters are cold. Our home is a modular, 1800 sq ft, so the insulation is not the best, and the place is full of windows and sliding doors. I'm sure we loose a lot of heat with the crawl space too. We do have a free supply (wooded land) of wood to burn. I would think we would want to go with a forced air type, not the boiler type. I assume using the boiler type would require installing all the water
Piping in the home for the heat. My main questions are... with the forced air type burners, do you still use the blower on your existing furnace to pull the warm air to the house, or do the burners have their own fan system outside on the unit itself to push the warm air in? Does anyone have an opinion on which one works the best or things to look for and avoid? Thanks for the help.

Consider this: do you have enough free time to commit to chopping and loading wood? I assume that you have no objections to what will be a changing landscape as the trees around you diminish. If you plan to burn freshly harvested wood, expect a lot of soot production and subsequent cleaning of the fire chamber. If I were you, I would explore other alternatives first.

First of all most of those burners have to be installed outside unless they are certified for use in a modular home.
Second there is no such thing as a free wood supply and you will find that out as you cut it,move it,split it, stack it,and move it again. Then you have to clean up the ashes. Chain saws and log splitters cost money also. There is no free wood.

The units you are talking about are expensive to buy and install. Since your home is energy inefficient as you mentioned it will also be difficult to heat with wood since you will burn more wood to heat it since it is inefficient.

The point I am trying to make is take the money and improve your homes energy inefficiency before you spend money for another heating source. It might surprise you when you fix the windows/doors and the crawl space situation with how comfortable your home becomes and how much less you spend on utilitys.

The air type would be the cheapest to have then the water type. The water type is actually not water filled since if the boiler is down it will freeze so you have to fill the system with antifreeze. The connecting lines,coils,bleeders,pumps, and all other associated parts cost big bucks that is why the air system is cheaper.

A neighbor of mine did the water system as you call it with a stand alone shed for the boiler. The total cost of all materials and boiler was about 10,000.00 and naturally he did the labor himself with me playing armchair supervisor/designer. 10 grand buys a lot of oil,gas,or electric. His system works well but he is getting tired of having to go out into the cold to stoke that baby up and the wood as he says in another subject. Just another gung ho project that enough thought was not put into from the beginning and now that he is getting tired of going outside to load it up it is getting near its ending. Probably by next year he will sell it to another energy saver person.

Ok, thank you for your opinion. I understand the wood takes a lot of work, we already have the equipment and cut,split and stack some on a much smaller scale. What, in your opinion, would be the best way to insulate under the floor? There is already insulation in the crawl space that seems to be in good shape. The windows are newer, so they have some energy efficiency, but there are just so many of them. Is it possible to have that foam expanding insulation put into the walls in a modular just like a normal home, and do you think this would help? I was wondering if anyone has a ball park figure on cost. The home is 32Wx76L, and plain old ranch. Thanks for the insight!

Usually the type of home you have is insulated from the factory. Under the floor just needs to have bats installed and a plastic sheet on the ground/gravel to help keep down the moisture. No idea on price since the equipment and materials cost different in different areas.

Get yourself an energy audit. Be sure they have a thermal imager, and do the walk-through with them and write down everything they find.

You can then pick the biggest bang for the buck upgrades.

Yes, outdoor wood burners sound great on paper, but they are a significant commitment.

If you're already doing wood on a smaller scale then perhaps look into upgrading your wood stove to a more efficient model that is larger for a longer burn time, or add another stove in a strategic place. People seem to be snatching up anything that burns wood in my area so I'll be you'll have no trouble getting rid of your current model.

Also, don't forget about Pellet stoves. Their efficiency is in the high 80s, they're a little high tech and expensive, but are easy to install and pretty easy to use.