I'm in a condo and most of mine are on a screened in patio. I've closed the hurricane shutters and turned on the grow lights plus a few additional shop light. It raised the temp from 60 to 65 so far.
Here's a great article I received in email today from Martin Motes on Protecting Your Orchids from Cold Weather. He's in south Florida. Good luck and may the warmth be with you! Constant Contact : Unexpected Error