I have a refrigerator and washer and dryer in a non heated storage unit for the last 3 years. Will they be any good after all this time?

Its possible that they will be. Here is the problem. Depending on where you live the washer may have problems if it had any water inside of it that froze. Im not talking in the tub but the pump or filter. The refrigerator should be fine. Your only other problem may be that anything rubber may have rotted. So check carefully before use. You can actually use a garden hose and run a cold cycle while the washer is outside so long as you have it on a stable base to test for leaks.