If you use natural gas, oil, or are all electric a wood burning boiler may be an alternative heating method. You would have to look at the application and run the numbers but worth a look. I am told this is a more cost effective way to heat your home, shop, or out buildings.
They come in all sizes the average size uses about a cord of wood per month. A small unit runs around $5,500 a large commercial unit goes for around $15,000. Installation runs about $1,800 depending on the applcation.
There is a 50 minute interview with a couple of Dealers, that has some good information. Long but infomative.