Have seen some recent posts about Proofing Boxes thought I would add my 2
cents worth. The best proofing box I've found, emergency or not, is my
oven, which happens to be electric.
Leave the light on and it holds at about 90-92F. But you can experiment
with different size bulbs (I use a 40watt), and an thermometer to see what
your oven does. If I want it a bit cooler I prop the door open a bit with a
hot pan holder, then stays about 82-85F. But get a good industrial grade
thermometer from you hardware store so you get good readings when you run
your tests.
If you have 2 ovens use different size bulbs in each, for different temps.
I also use it to make yogurt overnight, it works great!!!
Mike