Sedum rubrotinctum and air conditioning

[Brontosaurus]

My S. rubrotinctum really took off and has grown gigantic over the year that I've had it. Yesterday, I heard this noise like small things falling on the floor, and I couldn't figure out what it was, until I noticed that all the leaves were falling off my plant. I picked them up to so I can plant them in the future. I noticed this morning that even more leaves have fallen off. Do you think this could be from my use of the AC in my flat? My air conditioner is only a couple of meters away from the plant. When it's not on, the temperature is about 30, and I run it at 16. I wonder if that sudden change in temperature could stress a plant.