Heating from Dometic A/C

[crushor]

Knowing this is the summertime, but wanting to increase my TT to do list...I was wondering if anyone had the Dometic stand alone A/C that had the heat mode? We used our CC this winter and ran the furnace...which heated great but was a propane hog, but I am trying to find out about adding the heat option to the A/C. The switch and temp controls are already there but it does not generate heat. Any thoughts? Additionally we have the main A/C that is central air style. Thanks.