After putting the kids in bed, I was watching tv. I decided to load our furnace at 10:00pm and was going to close the damper a little later or let the thermostat go. Well I fell asleep, and woke up at 10:45pm to that hot smell. I figured I would close the damper via thermostat and go to bed. Well my wife let me know when she got home this morning, I never latched the door closed last night. I don't know how it happened, but don't want it to happen again! Everything looks okay, and no damage, but a bit scary. I've had the furnace for about 4 seasons now and never had this happen. It got down to 16* last night, and the house hit 77* according to the thermometer. Everything stayed safe because of clearances and guidelines that were followed during installation. It made me feel like a dumbass, that's for sure!