High electric bill and hot floor?

I suspect that the warm spot is the same that it always has been, just that now you are looking for "problems" and noticed it.

Here are some possibilites of high electric usage.

A short in the water heater elements.

A tap by a neighbor - more common in duplex/row houses/appartments, but it has also been know to happen in standalone houses.

A well pump (or sewer pump) with a hole in the line so that they run all the time and just pump the water in a circle.

An pump with the emergency heating elements that are on all the time.

Turn off all "readily known" electrical equipment and look at the disc in the meter. It should be stop or barely moving. Because of things like door bell and furnace/AC transformsers, standby on TV and microwave clocks, etc it will probably not be stopped, but fairly slow moving. If not start fipping circuit breakers un note the affect on each on the rate of the disc and find out what is drawing the large amount of current.

what you're describing sounds alot like something that happened to me. My termite guy drilled thru my hot water pipe...causing my bill to go up and my floor to be warm, Eventually mine told on itself by water bubbling up in the back yard. maybe you have a busted pipe causing your water heater to run constantly. To check it out, turn off all your faucets and toilet valves and go look at your water meter. If its turning...you got a broken pipe

If the hot spot is on a slab then you could have abusted hot water line under the floor. Chaeck your water meter with everything turned off. It should not be moving.