Yes, it doesn't get very cold in Florida in the winter. But, when it does we still need to turn on our furnace. If you have a gas furnace and your not getting heat this is most likely your problem. There is a small part called a "flame sensor" in your furnace. Most of them are easy to reach and only held in by a small screw.
Just turn off your furnace and remove this sensor. You should first try and clean it. Or you can just replace the part with a new one. The part is very cheap vs paying for a HVAC man to come out to your house to look at it. And of course that is not going to be cheap. Here is just a short video telling you something about this.
DIY Quick Furnace Fix - Flame Sensor - YouTube