1. Assess Your Existing Windows

Assess whether your windows should be retrofitted, or replaced. While most new windows have labels indicating their energy properties, such information is not often available for existing windows. 

2. Meet the Energy Code and Look for the ENERGY STAR®

Windows must meet the locally applicable energy code requirements. Windows that are ENERGY STAR qualified typically meet or exceed energy code requirements. A home's climate and location determine the relative importance of heating and cooling energy use, the applicable building energy code requirements, and the qualification criteria for ENERGY STAR windows.

3. Look for Efficient Properties on the NFRC Label

The National Fenestration Rating Council (NFRC) label is needed for verification of energy code compliance. The NFRC label displays whole-window energy properties and appears on all fenestration products which are part of the ENERGY STAR program and provides the only reliable way to determine the window energy properties and to compare products.

4. Compare Annual Energy Costs for a Typical House

Look at Window Performance Ratings to compare the annual energy performance of different window types and design conditions for a typical house. Find manufacturers who offer windows and skylights within the generic results shown. Learn more about manufacturers' specific product options.

5. Customize Energy Use for a Specific House

A computer simulation program, such as RESFEN, lets you compare window performance options by calculating performance based on utility rates for your climate, house design options, and window design options.

6. Choose a Durable Product

Make sure the design and workmanship of the window result in durable window installation for your specific application. Window warranties can be an indicator of the reliability of the window and its manufacturer. Durability may vary with location. Aspects of window durability that deserve attention are frame and sashes, insulating glass seals, weatherstripping, and local requirements for structural integrity.

7. Ensure Proper Installation

Proper installation is necessary for optimal window performance, to ensure an airtight fit and avoid water leakage. Always follow the manufacturer's installation guidelines and use trained professionals for window installation.

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