Brinmar is the leading manufacturer of air conditioner covers since 1975. Our standard cover design has been time tested and laboratory approved by leading air conditioner manufacturers for over 35 years. We have sold millions of covers. Most of these covers are our standard design - without air vents. To date, we have yet to receive a single complaint about condensation causing damage to the air conditioner. Not a single complaint. Our standard cover has three design features that account for this: 1) Each cover is ½ inch short in height. This permits air flow at the bottom of the cover where any damp air could accumulate. 2) Our vinyl covers are made with heavy duty industrial vinyl and have a supported fabric layer that provides insulation qualities. 3) Each cover has a large opening or slit to accommodate the electrical and A/C lines which allows air to escape, so the cover is never air tight. Still, if you’re not convinced and want more peace of mind, get one of our top vented covers. They provide an additional of 32 additional square inches of cross ventilation. Our standard design is by far the more popular choice.