Licklog,
We sorta kept our old furnace. It's a good story. I had bids from maybe a dozen suppliers and about half said our 18 year old furnace would be OK, the other half said it was too small.
I went with a guy who had a good reputation, but who said our old furnace was OK. His bid was $3,600; some of the others ran upwards of $12,000.
He installed the heat pump, then called me a week later. Said one of his guys thought the furnace was too small, copied down the model number & called the manufacturer, who confirmed the size as being too small.
Said since he screwed up, he would GIVE me a new furnace!
When he came, I asked what his cost was on the furnace. Said there is a really high markup on them; that his cost was about $600 and it listed for something like $1200-1500; I don't remember exactly. To be decent on my end, I gave him a check for $400.
At $4,000 for a new heat pump and furnace, I think I got a really good deal.
Our electric bill has gone up about $50 a month for Oct-April. We used to use 800 gallons of propane a year; now we use less than half most of which is used for water plus some supplemental heat in December and January.