It's possible that the installation assumed a particular temperature range in the surrounding area. The water was still heated to the proper temperature but bec

It's possible that the installation assumed a particular temperature range in the surrounding area. The water was still heated to the proper temperature but because the surrounding air was lower than design parameters allowed, was leaking more heat than designed for, requiring the water heating to work harder. Zero idea if any of that is correct but it shouldn't be ignored as a possibility and is one possibility that could be eliminated very quickly if not true.