Hopefully I did this correctly. I setup a rule that runs from 8pm - 8am. If my room temp hits 68 or lower, turn on heated mattress pad . If 69 or hotter, turn off but if it's 3am and I am not home, turn off. Last turn off heated mattress pad switch at 8am.
Required expression: Time between 8:00PM and 8:00AM
Trigger Events: Temperature of My Room Motion <= 68.0
Actions:
On: My bed warmer (command only switches that are off)
Wait for event: Temperature of My Room motion is >= 69.0
Off: My bed warmer (command only switches that are on)
The second rule can be triggered at two times: 3AM and 8AM to turn off the mattress pad. With an IF block at 3AM to only do so if your presence sensors are "not present".