While waiting in a commercial establishment, I perused an old Martha Stewart Living magazine, might have been the Sept. 08 issue. She indicated that a cold water laundry wash in the very cold winter may be too cold for the detergent to function properly (even detergent specifically made for cold water) because the water is too cold. Thought I'd share this info. Actual temperatures were mentioned in the article if anyone needs further information.
I avoid cold water washing because I have had to have outlet pipes replaced. They were completely bunged up with washing powder. To avoid this the repair man said that you have to wash very hot loads now and then.