Neither house would qualify for a deductible loss. They are both your personal property, and personal losses aren't deductible.
Some people convert the house they've moved out of into rental (if you don't mind being a landlord). That way, when it sells, it's a business loss & is deductible. (Warning, because of depreciation and the possibility of suspended rental losses, you might discover that you no longer have a loss on the sale ... it gets a bit complicated.)


