Katie, I live in upstate NY, where except for some beastly hot summer
days when I wouldn't bake, anyway, my tree-shaded house temperature
rarely is warm enough to make dough rise without a bit of help. I use
my oven, warmed until 100 F is reached and then turned off. Opening
the door for a couple of minutes cools it down just enough. Dough
rises beautifully, and if it's in the formed final rise, I leave it
there, set the temperature for the desired setting, and turn on the
oven to bake the bread or rolls. It hasn't failed yet. Another method
I have used is filling a bowl or pan with hot water and putting it in
the oven's bottom rack without heating the oven and put the dough on
the top rack. That works, too.
You can construct proofing boxes fairly easily, but I let my oven do the work.
Ellen