I do use a vent, L&L downward draft coming out of the bottom. Because we built the shop and then put the kiln/vent in, we were able to put the vent where we wanted it. So, a hole was cut through the side of the shop and the vent mounted and everything around was sealed up. Like Neil said, the heat is welcome part of the year. And in the warmer months, I open windows, doors, and run a fan. I have always used a vent, so I really don't have a comparison. Looking at dhPotter's pictures though, that tells me that there would be a difference!