High Impact Defender Serie Pella Windows DP- (+/-70).Common DP Ratings for WindowsDP-20 to DP-30: Standard residential windows for low-wind environments (typically inland, suburban areas).DP-35 to DP-50: Heavy-duty or impact-resistant windows required for severe weather, coastal areas, or high-rise buildings.DP-60+: Custom commercial or high-velocity hurricane zone (HVHZ) requirements (e.g., coastal Florida).