Probably not too much. The cool start will slow things down a little initially, but should not have a tremendous impact on the resulting beer. I would make sure the hair dryer is on now, and let it go like normal. I would be willing to bet that you will have no ill-effects whatsoever. I would be WAY more worried if the brew was too hot for a day than too cool.
"Give a man a beer, and he will waste an hour. Teach a man to brew, and he will waste a lifetime!" Bill Owen