Hello,
Maybe you need to tighten your system up a little. If it worked for 38 years, what was the kw consumption over the years? If the same, then maybe a little tweaking can be done? Using CF instead of incadescent should same considerable, depending on your habits of leaving on lamps.

Contact WF for a local rep. The equipment is kinda expensive? KISS. If it worked before, find out what changed.

Seeing as you already have a well, your least expensive route (aside from fixing your existing GSHP) would be another open loop GSHP.

Let the installer worry about the well pump etc., but can your well still supply all the water you need? You will also need to know the water temperature as well (should be in the 70Âs in Florida). You may be able to find the specs on GPM required on the web anyway by downloading the installation manual of the equipment youÂre considering.

SR

Here is a link that might be useful: how-efficient-is-it-magazine.com

Consider a system that doesn't use water. "This system uses copper tubes placed deep within the ground to utilize the constant temperature of the earth as a source or sink of heat to be transferred to a circulating refrigerant."
About a 10 or 12 foot circle is disturbed on your property and a narrow trench to run the lines to your house. We have the compressor unit in our basement and it doesn't make as much noise as our old oil burner. We also added the hot water option.
The cost of heating oil as high as its been is cutting down the payback time

Here is a link that might be useful: Advanced Geothermal