If your home is heated with gas it should not be particularly expensive to keep warm.
If you have a heat pump the thermostat should have an "emergency" setting. That is for days when it is extremely cold and the heat pump is not getting the job done. What that setting does is activate electrical heat strips to generate extra heat. That really gets the electric meter spinning and is quite expensive. You should seldom or never need to use that setting in central Florida.
Many people run the heat for a while when they get up in the morning to knock the chill off the air and then rely on the rising sun to maintain their comfort through the day.
You can also wear extra clothes or a sweater through the day.
By all means, stay warm.