The obvious should be stated - the absolute cheapest way to heat your house is geothermal. It should at least be considered. Next cheapest is air source heat pump particularly with an efficient mini split. It seems to me that converting the whole house to a standard ducted heat pump has a fairly low upfront cost and a fairly low run cost. It is a compromise for upfront cost and ongoing cost. I can't see why anyone would recommend propane - unless the goal is having generator backup heat. Are you talking paying $350 for 12 months? A heat pump with electric backup should be 50% of that or less depending on climate and what system you buy. It would seem like Carrier Greenspeed would pay off for such a high heating need. You would probably save closer to 75% compared to oil. So even though it might be $20k installed, the payback is 7 years. You really need to experience a well installed forced air system. I don't know mine is on. I fail to see how a gentle circulation of air through a filter creates dust - it actually reduces it. And then it humidifies it.

Oh yeah, almost forgot, one thing I find odd in all of this is that after 45 seconds of flame ignition - the blower motor is supposed to kick on. However at 20 or 30 seconds - their is already 'resistance' quickly building in the 2ndary hi limit switches - they are technically still closed and the LED hasn't started flashing yet. And within about 60 seconds (the fan would now be about 15 seconds overdue) the hi limit circuit goes open. The 15 second window seems pretty tight - is that about what it should be?

I live in Michigan. My home is a colonial with approximately 2400 sq ft. The current heating system, when it worked, was excellent. The house would heat up in a matter of minutes. The temperature also stayed pretty consistent. In the old house we also had the furnace replaced. I hated, hated, hated the new furnace. The furnace would turn on, the house would get warm, then the temperature would go down about 5-7 degrees before turning back on. The air was also super dry and we had never had that problem before. I don't want to make that mistake again. Here's the actual information from the quote: Remove and haul away old equipment. Install Carrier 110,000 BTU 80% efficient furnace with 35ft chimney liner. Install a Carrier 3.5 ton 13 seer central air package with 25ft copper lineset, ac pad, a coil cond (can't figure out what he wrote) pump to pump to laundry. Elect (can't figure out what he wrote) and disconnect. All permits, sheet metal, work, taxes, and cleanup included. Warranties: Furnace - 20 year heat exchanger Parts - 10 year Service & Labor - 2 year Total Cost - $4890 Extras: air cleaner - $200 95% Carrier 100,000 BTU furnace $700 more It seems that it makes more sense to get the 95% or 96% furnace but I really don't know.

2 separate units will do the job, but cost of maintenance and break downs of 2 units as opposed to one with zone controls will in the long run be more costly. You have 2 units to maintain, you have 2 units to repair when they break. Tag team event. One system breaks down one month. The other system breaks down the next month. Doesn't always happen this way... but it could. zoning has to be done right. So what does that cost? I don't know I am not there. 'Design, Design, Design' other wise 'Trouble, Trouble, Trouble'.