I have a 20 year old Day & Night heat pump. When the time comes to have it replaced, I'm wondering if it would be a good idea to get a propane model, and replace my water heater & stove with propane models as well? I currently do not have a propane tank, so I know there would be some cost involved.

One of my motives are cost (although it may not be cheaper for propane, I'm not sure).

The other is so that I can have my 5500 watt (continuous) gas generator (and transfer switch) installed, and be able to have supplemental power. I live in Sutter Creek, California, and we have an average of 3 or 4 power outages a year (the most recent one lasted over 24 hours). I have a small house (1400 sq. ft.), but I have a well pump that would also need to run from the generator (I'll ask these generator-related questions in another forum as well).

Can anyone tell me an approximate cost to get a propane tank and plumbing installed? Is propane a much better value than electricity these days?

Call a local propane supply company. Prices vary from state to state.

You will have to do a cost based analysis as to the difference in cost from electric to propane. This analysis may also be offered by the propane company.

You can do the analysis yourself by using Google and typing in fuel cost analysis propane to electric or something along those lines.

You will need you KW rate and the cost of propane plus the efficiency of the furnace you are going to use.