Balance seasonal priorities

Questions for the written comparison
CompareProduct evidenceOpening and installation evidence
Heat transferExact whole-product U-factorInsulation continuity and retained-frame condition
Solar loadExact solar heat gain coefficient and visible transmittanceDirection, shade, overhang, and glass area
Air movementReported air-leakage rating when availablePerimeter sealing and operable-joint condition
MoistureCondensation resistance when reportedFlashing, drainage, exterior joints, indoor humidity, and source investigation

Interior condensation, exterior condensation, between-pane fogging, and water leakage are different observations. Record where and when moisture appears before treating it as evidence for a particular replacement scope.

  • Compare the exact certified configuration, not a sample label.
  • Define flashing and drainage for the wall assembly.
  • Avoid sealing details that block intended drainage paths.
  • Document any rot, staining, or soft materials found at the opening.