If you have access to a lot of fire wood or tree services that will dump for free. I would go with the Central Boiler wood or duel fuel boiler. I have one and love it. Mine can be put up to 300 feet away from the house so your mess with the wood isn't too close. I put mine right at the end of the driveway. The tree trimmers drop of wood for free. I have a medium size one at 500,000 BTU. I load it every day once. I can go three days if I load it to the top in forty deg weather. When it's zero I have to load it to the top once a day. I have a 2700 sq ft house with just 2 by 6 rafters. Drywall on one side and shingles on the other. Plus I have old aluminum clad windows so my house is not very efficient at keeping the heat in and the cold out. I paid $9,000 for it and it will pay for itself this third year. I have fun loading it. The door is 21" by 30" and I roll 20 by 28" logs up a 2 by 12 board. I have put two popular logs that size in it at the same time and it went for four days in 40 - 30 deg weather. If you cant get wood very easily I wouldn't go this route. They do go through a lot of wood. You can burn pine or anything not chemically treated. You can't burn garbage, plywood, cardboard, or paper because it builds up acid on the walls. It heats the hot water too. It has a pump that runs continuous 1.4 amps 110 volt. Then another that works the zones when they call for heat .7 amps. I have a 12' wind turbine in a bad wind site. The wind has to be 20 mph or better to keep up with the boiler. I am on grid, and at least I have back up if the grid goes out. I have to invert to 110 so maybe if you can get your model with a 48 volt pump or what ever your dc voltage is going to be you could save power.