Your cold weather conditions are different than my area. That is sad though that you lost them. My scheffleras, and jades, they are out all year long, and they endure here. Maybe because we do have a quick warm up the following day then goes back down to the lower temps during winter. I guess these plants endure here since it is only during winter season that we get good levels of humidity and some rain, after that they get 6 months of dry air and dismal to no rain.
But I always find jades to be very tough. I have almost killed a Crassula ovata 'Gollum' but it did come back slowly the following year. It was really pitiful to look at then, but it surprisingly came back and came back much bigger too, once I have moved it closer to the house. It is now a big monster plant, too top heavy as well. As long as I see green, I see hope in them, as long as the stems still fell a bit stiff, it can still dry out, scab over and heal.
Feb 9, 2012
End of Feb 2012
Same plant Nov 2014
Crassula ovata is less finicky for me..it will just turn brick red when it is feeling very cold, it has even gotten bad hail marks at one time on its leaves, but it stays on, and grows so well.
Feb 2012, same period my Gollum was fighting for its life, this jade was just brick red, I guess our house helped shielding it from the a lot of the windchill too: