Geraniums will bloom in the winter in Tennessee, just have them inside. Most people save their geraniums over the winter by digging them and hanging them upside down and then replanting in the spring. I never had much luck with that, hit or miss.
So last year when it came time to bring in the outside potted plants I decided I would try just moving this one to the glassed in porch. It does stay rather cool out there, not heated. But it is warm enough for the Geranium to actually like it. This is the 2nd year to have blooms through the winter.
I also have a walk up attic (like the old houses) that has a window. That is where I put most of my outside potted plants during the winter. They do better there than they did next to a window in the basement at our last house.