WHAT IS A MIAMI IMPACT WINDOW? From China WDMA : A impact window combines a strong frame and sturdy glass, can withstand at least 140 mph wind, and our Miami impact windows are designed to handle an incredible amount of damage of up to 180 miles / hour wind! Even if the glass is broken due to impact, but also to maintain the integrity of the glass. Impact-resistant glass doors and windows are the must-have choices when building a house in South Florida. How much do impact windows cost? Impact Hurricane Windows Cost includes Window and Installation Costs. The average install service cost of hurricane windows is about $40~$100 per square foot depending on the difficulty, or about $500~$1000 per window for the most normal sizes. Hurricane window cost starts at about $200 for small fixed windows and may cost up to more than $2,000 for large windows that open.