We have had to replace our Dometic AC unit two times in only 3 years of owning our camper. We run the unit according to the manufacturer guidelines and do not over work the unit. We never set the thermostat to less than 75 degrees (usually set at 77). The first unit was replaced 11 months ago and now we have had to replace that unit. This unit was paid for out of pocket as it died less than 5 days before a scheduled vacation and our approved service center couldn't help us for 3 weeks. Is there a reason I should have to replace these units annually??? Is it due to poor manufacturer design (only one unit for the trailer)? Is it due to poor ducting? We are at a loss. The first unit kept freezing up and this one just started blowing hot air out of nowhere (compressor running). Any thoughts or suggestions? I certainly don't feel we should have to put out this kind of money each year.