A.Paul Fisette, director of Building Materials and Wood Technology at the University of Massachusetts Amherst, responds: In order for a ridge vent to exhaust, you need a pathway and a reliable driving force. Both a single-sided and a double-sided ridge vent provide a pathway, so the important question is this: What is the main driving force that pushes attic air up and out of the ridge vent?
While wind direction can induce roof venting — and it's been shown that even soffit-only venting can draw air out of roofs — most often the answer is the buoyancy of the attic air. If there is a fair amount of heat loss from the house into the attic, then the buoyancy of the warm air rising causes it to escape at the highest point, the ridge.
to continue reading