You'll want to pay for heat and make sure they have a cover for the pool at night when you aren't using it. We live in SW Florida and have our pool heater set at 86 degrees. We have a solar pool cover as well. Today it's in the 60's (temps dropped last night) and I wouldn't want to be in the pool without the heater.
Even with record heat an un heated pool would be too cold to enjoy in Feb
When would you say paying for heating becomes unnecessary? I'll be down in Orlando for a conference the first week of April and we've rented a house with a pool.