Back in the 1970’s some smart guys in Minnesota decided fireplaces could be much more efficient. Traditional fireplaces with dampers wide open pull the warm air out of your house when in use. If the damper is not closed after use, they can also let cold air into the house. A Direct Vent Fireplace does a great job pulling 100% of its combustion air from the outside AND dumping the exhaust back outside as well. PRO TIP: Direct Vent INSERTS go into pre-existing brick fireplaces while NEW CONSTRUCTION Direct Vents go where there is no existing fireplace.