OK my sunroom is not Florida but it's much closer to my house... just outside my kitchen door actually. I highly recommend one of these if you live in the north! It's my winter hangout...
For heating, I have a vent from my house plus baseboard heat all the wall behind my bird cages. There is also a heat pump / air conditioner, if I need to warm it up or cool it down. Using just the heat vent from the house and baseboard heat turned to low, I can keep the room mostly between 65'F and 55'F. My winter "low" so far has been 49'F, the morning when it was 8'F outside last week.
I have found that keeping the temps on the low side seems to benefit my plants and slow down the pests. The humidity also stays a little higher with less heat and I can pump it up 10% by just using a hand-sprayer with water on all the plants.
My sunroom is a Four Season Sunroom so the glass is somewhat UV filtered - so not perfect as a greenhouse - BUT enough UV gets in so plants grow. I have a solid roof with 2 skylights.
I winter 4 large potted citrus trees in the sunroom. A "Eureka" Lemon, which admitted lost some foliage by being taken inside - but manages to survive all winter. It is even flowering now.
I also have a "Jaffa" or "Shamouti" Orange:
And a 33 year old Calamondin "Orange", planted by my mother from a seed in 1982.
Some other plant highlights... I have 2 7-foot Coffee Plants (got on eBay from Hawaii):
I also have several Chamaedorea palms, which do well without sunlight. I have found that Chamaedorea tepejilote is especially nice in the sunroom. This species seems to burn from direct sun outside so it is perfect to keep all year in the sunroom - though I usually put them outside in the shade during the heat if summer to get extra growth out of them. I got them mail-order from a nursery in Hawaii.
I also winter a big collection of Crotons in the sunroom (they go outside in summer for better coloration). I was happy to discover that they do just fine in cooler (than room) temperatures. I have about 10 cultivars.
I also have 6 bird cages in there with an assortment of birds... some of whom get free-flight time in there.