I feel it makes a big difference, for me, personally wouldn’t use it uncapped unless I had no cap to use. When the cap is not on after 15-20 seconds you can see vapor escaping from the top of the heater unit. I can’t imagine it’s better to allow all of the hot air to rise on out, although I also can’t imagine it makes a MASSIVE difference...but definitely prefer to keep the herb/load capped If possible to trap all the goodies in as much as possible.Does anyone care to express how important they feel that the carb cap is on the Vrod when using for flower only?