A great way to tell if your venting system is functioning is to go outside and look for the exhaust. This video shows the Builder's Best Aluminum Eave Vent. The dryer is on so the damper is open and the exhaust is clearly visible. The vent is flush against the eave, so when the dryer is off, the damper is closed and you don't see the vent. More details are available here: https://buildersbest.com/products/aev...

Buy it the Eave Vent here:
https://www.doitbest.com/shop/heating...