The primary difference between air conditioners and heat pumps is heat pumps can both cool and heat. The trade-off is that the air conditioner is a little more energy efficient at cooling. Generally, a heat pump heats best down to about 40 degrees. Below that outdoor air temperature, you may want a furnace as your primary heating source.
The weather in Southern Florida, California and Texas is hot for most of the year. A heat pump’s warming ability would see little use each year. Plus, because you run your air conditioner so much, you want to invest in the most energy efficient air conditioner with a high seasonal energy efficiency ratio (SEER).
A heat pump might be an ideal system for moderate climates like the Mid-South. Tennessee, for example has moderate spring and autumn seasons, and very hot summers. So, a heat pump cools in the summer, then provides inexpensive electric heat in the spring and fall.