Residential refers are built for zero clearance install and NO need for backside air. Residentials take air from the lower bottom louver and with the fan circulate the air over and out the bottom front of the refer. I know of NO OEM, that uses a vented door or roof vent. If OEM installed Residential there is NO roof vent and the outside access door is a solid door. That outside solid door is there for backside access for service. FYI, some Jayco 5th wheels have NO outside access doors at all for their residential refers. Doug