The short answer
Create one opening schedule, then compare each proposal line by line: exact product, size and operation, complete ratings, insert or full-frame method, flashing and sealing, interior and exterior finish, known repairs, allowances, permits, protection, cleanup, schedule, payment terms, change orders, and separate product and labor warranty responsibilities.
Normalize the openings
Use the same window count, room or elevation identifier, measured size, operation, and project priority.
Match the product
Record manufacturer, line, frame, glass, finish, hardware, screens, grids, and the exact NFRC label.
Match the installation
Identify what remains, what is removed, water-management details, insulation, sealant, trim, and finish.
Expose assumptions
List damage allowances, permit responsibility, access, exclusions, lead-safe work, disposal, and cleanup.
Read the contract terms
Compare payment milestones, financing terms when used, change-order process, schedule language, cancellation terms, and warranty administration.
| Compare | Question | Evidence to keep |
|---|---|---|
| Which exact window? | Product schedule and matching label | Model, size, operation, glass, finish, and ratings |
| Which installation? | Written method and opening detail | Removal, flashing, sealing, trim, repair, and drainage scope |
| What can change? | Allowance and change-order language | Unit rates or approval process before extra work |
| Who is responsible? | Contract and warranty documents | Provider, installer, manufacturer, permit, cleanup, and service roles |
Common questions
Common questions
Should the lowest total win?
Sources
Sources
- How to Avoid a Home Improvement Scam — Federal Trade Commission
- Window Installation — U.S. Department of Energy
- Window Energy Performance Ratings — National Fenestration Rating Council
- Renovation, Repair and Painting Program for Consumers — U.S. Environmental Protection Agency