What is the coldest temp you've started your Honda 2000 in?

We run generators, air compressors, and lots of things that don't like to start up here in the Canadian winters. One trick we often do at work if we need to, is to run the truck motor with the generator in front of the truck exhaust for five or ten minutes. This will warm up the generator, and the oil inside enough that starting it is much easier. We use air compressors for building that wont start unless you heat them up first. Once they are running, they create enough heat on their own.