We bought a CO monitor when we got the new caravan about 2 years ago. We bought the "house" model as the "caravan" model was not available at the time. Is there any difference between these two models? We have noticed that the CO monitor alarms if we cook using the gas cooktop with the windows shut. The blurb on line says to only use the caravan model in caravans. Is this because the caravan model is less sensitive than the house model?