I have palm trees in my back yard...
OK, you win.:sad1: Damn, you also have a reef out back. I have 54 degree water full of Great Whites...
Polywise,
It would take a pretty detailed analysis to see which would be more cost efficient (electric heaters or gas fired loop water). If your hot water tank was pretty large, you may get by, but if its smaller than say 50g, your boiler will be short cycling and wasting gas. There are ways to limit the heat loss of your system, but you'll need to look at the whole package.
Denver,
Good point, though this only holds true while you are using the hot water.
I had an idea along the same lines for my RO/DI feed. The incoming cold water line would tee off and run through a long poly or PEX coil in my sump then back to the feed line to the RO.
A solenoid valve on the shorter straight run to the DI (between the Tees to/from the coil) would close when the tank called for cooling.
This would then route the domestic water through the coil in the sump, cooling the tank, and warming the water feeding the RO. Normally the valve would be open and the water would not flow through the coil, as the path of least resistance would be through the straight shot (12" of 1/2" pipe, vs. 50' of 1/2"PEX). This of course would only work when the RO was running.
I guess you could do this same setup to your main house feed so that whenever the water ran it would be available for cooling. (And, again would technically require a double exchanger and backflow, if you went by the book)
Obviously good controls and sequencing are a must here, but its very doable.