I take you don’t have gas seeing how you’re using propane?
We don’t have gas where I live either and our choices are between propane, fuel oil and electricity. Fuel is about $2.60 a gallon, propane is $2.25 a gallon and electricity is $.18 kilowatt hour. I think all three of those are the highest in the country. Seeing how I’m heating 4700 square foot, this is a topic that I have an interest in.
As John already mentioned, sealing up your home should be step #1. Pull a negative pressure on your home with a fan and go around all the doors and windows with an incense stick. You’ll find the leakers pretty quick. The best way to do this is to call someone over to do a home efficiency evaluation. They will take the entrance door off the hinges and then put a door blower on it. Then they read the air exchanges and give you a summery report of how well it’s sealed up. When the guy has his fan up and running, you go around the house (on the inside) and look for leaks with smoke. We used to get reduced finance rates on homes here in Alaska if they would meet a particular level of efficiency (up to 2%). I put a lot of work into my home to get this interest rate. When I had the rating test done, the guy couldn't believe how tight is was. At that time it was the only scribe fit log home in the state that ever got the five star plus rating. Afer it started to settle and things started moving around, it started leaking. I went from useing 150 gallons durring the coldest month to 400 gallons. After getting that $800 fuel bill, I checked it for leaks again and sealed it up everwhere I could find leaks (mostly around the doors and windows). I'm back down to using very little fuel.
If you don’t want to do that and still want to go with a portable heater, I can’t help you. I think they’re all junk and unsafe and I’ve responded to more than one home fire because of the damn things. The only thing I’d consider would be Toyo. They are very efficient and maintenance free. They just run and run and run. (My buddy is a heating tech and he sells and maintains these things)
They run off #1 fuel oil or kerosene, and are easy to install. They are very popular in Alaska. They are direct vented, so you cut a 2.5” hole in your wall and stub out the exhaust. You’ll also have to run a fuel line to it and have a fuel oil tank (which may suck for you).
http://www.toyotomiusa.com/products/LaserVentedHeaters.phpIf you are interested in installing one of these, give me a holler. I can get you any information you’d like.
