I'm not sure which year the auto-ventilation became available - '92 maybe? You can tell if the heater option is fitted by pushing 'timer' and 'temp' together - it will say 'inv' if the heater is installed. It would be great to have up here (in Vancouver) as it starts to get colder at night. From what I can see in the manual it appears that the heater is actually gas fuelled. Must be similiar to the Espar heaters they use on buses and boats. If anybody has this option I'd be interested to learn more about it.