Will Vented Drip Edge allow weather infiltration due to the gutter becoming packed with snow, ice or rain water?

If correctly installed Vented Drip Edge will perform well in winter weather.

When installing Vented Drip Edge make sure the vent is not installed against the top of the gutter. Allow a 1.25-inch space between the top edge of the gutter and the louvers of the Vented Drip Edge. If the vent is installed tightly against the top of the gutter, the vent louvers will be blocked as soon as the gutter fills (with snow, ice or debris). By leaving a 1.25-inch space, the gutter can fill without instantly blocking off the vent. Be sure the louvers on the vent are parallel with the ground so that wind cannot blow snow and rain directly into the openings. If the vent is installed with the lower flashing attached first, be careful that when fastening the upper flashing that it is not pulled up on the roof so far that it pulls the louvers up, opening them to the weather. Finally, be sure the fascia is installed so the top is above the louvers on the vent. The raised fascia will help protect the slot opening from possible weather infiltration.