Class 4 is the highest impact rating under FM 4473 and UL 2600 hail impact test standards — requiring the window to withstand impact from a 2-inch diameter steel ball dropped from 20 feet without the glazing cracking or breaching. The Wasatch Front is in one of the most active large-hail corridors in the western United States. While Utah building codes don’t require Class 4 windows (though some jurisdictions require Class 4 roofing), homeowners in foothill communities who have experienced hail events that cracked storm glazing or heavily pitted vinyl frames benefit from the protection. The more immediate consideration for many homeowners: insurance carriers that recognize Class 4 impact-resistant windows may offer premium discounts similar to those available for Class 4 roofing — potentially partially or fully offsetting the incremental product cost over the life of the discount. RainFire Builders can advise on Class 4 product availability in your preferred frame material and help you determine whether your carrier offers recognition before committing to the upgrade.