Wow, you are getting a lot of comments on this quickly. I will add my agreement to the bunch! I have mixed up many batches in the winter, carried down the stairs to the furnace room on the other side of the house. I never saw a difference between adding it in the kitchen or in the furnace room.
Yeast is very resourceful. I know folks have asked how much yeast they need to start 20-30 gallons before and get told 3-5 packets of yeast. When I make wine with crushed grapes, I sprinkle one packet on top of 25 gallons of must in a 32 gallon fermenter and it gets going strong in one or two days and eat the grapes up!