Hi Tim,
Welcome to the Heartland Owners Forum. Some of the new Cyclones have provision for a 3rd A/C unit in the garage. I'm not sure if the 3810s are in this group, but perhaps another Cyclone owner will know. If not, call Heartland Customer Service at 877-262-8032 / 574-262-8030. Have your VIN # ready. They can tell you for sure.