Based on the provided content from ACN Construction, there is no specific dollar amount or numerical range listed for the average cost of fiberglass window installation.

Instead, the guide emphasizes a transparent and personalized approach to pricing through the following methods:

• Itemized Estimates: During the initial consultation, the team performs precise measurements and provides a detailed written estimate where every cost is itemized upfront to prevent hidden surprises.
• Variable Factors: The final cost depends on the product line and customization selected (e.g., Marvin, Andersen, Pella, or Milgard) and the specific energy efficiency requirements of the home.
• Direct Request: The content repeatedly encourages homeowners to Request a Quote or Call 24/7 to receive specific pricing for their custom residential remodeling project.

While the text does not provide a baseline price, it notes that fiberglass is a long-term investment that can last 30 to 50 years and may reduce energy loss by 10% to 20%.