I posted recently about winterizing or not since the temps here in MN are dropping and we're leaving soon. I ended up turning the hot water heater on and cranking up the furnace to keep it warm in the unit. I've noticed that the CO2 detector in the bedroom is starting to chirp. I know the exhaust from the furnace exits at the rear of the unit. I wouldn't be surprised it there could be some CO2 leakage into the BR. I'm wondering if the detector in the BR is hard wired or runs on a 9v battery. I figure it's either the battery, or there is some leakage. I have a 2014 Winnebago Sightseer