CF1R for Window Replacement: Which Form Do I Need?
Two sizes sort a window job: 75 square feet and 16 square feet. Replace up to 75 sq ft at a U-factor of 0.40 or lower and a short exception applies; add more than 16 sq ft of glass and area limits apply. The form is CF1R-ALT-01-E or, with no field verification, CF1R-ALT-05-E, unless the department waives it.
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Replacing glass in the same openings
Section 150.2(b)1B sends replacement windows of the same total area to the U-factor and SHGC limits of the new-home package. Exception 1 relaxes that for up to 75 sq ft of vertical replacement: a U-factor no greater than 0.40 in every zone and, in zones 2, 4 and 6 to 15, an SHGC no greater than 0.35. Climate Zone 15 still needs 0.23 (Exception 3). Replaced skylights must reach 0.40 and 0.30. New glass in an existing sash or frame is a repair when it performs at least as well as the original.
Adding glass changes the answer
Added windows must meet the total and west-facing area limits as well as the U-factor and SHGC of Table 150.1-A. Up to 16 sq ft of added glass escapes the area limits only (Exception 2 in the 2025 Standards; the manual's worked examples cite older numbering). The manual's example of a house with 30 sq ft of window turned into two French doors shows how added area is counted.
Which sheet goes to the counter
Appendix A lists CF1R-ALT-01-E for prescriptive alterations and CF1R-ALT-05-E for prescriptive alterations "That Do Not Require Field Verification". Window replacements need no ECC-Rater test, and Section 10-103(a)1C names them as an alteration for which a department may require no certificate or only a simplified one. It also says that allowance never authorizes non-compliant work. Which sheet your department takes is its call, so ask before ordering.
- Averaging products that individually miss a number takes the worksheet CF1R-ENV-02-E (area weighted average), plus CF1R-ENV-03-E for SHGC.
- The installer's record is CF2R-ENV-01-E, "Fenestration Installation".
- If the prescriptive numbers cannot be met, the existing-plus-alterations performance route produces CF1R-PRF-01-E.
For the values by zone see new windows and Title 24; for a whole-house swap of single-pane units read the single-pane remodel page. The CF1R overview and CF2R page place these sheets in the sequence; our residential service prepares them.
Common Title 24 Questions
- What is a CF1R certificate of compliance?
- What is a CF2R certificate of installation?
- What is a CF3R certificate of verification?
- What is an NRCC form?
- What is an NRCA certificate of acceptance?
- What is an LMCC form?
Frequently Asked Questions
Not always. For alterations with no field verification, windows named as an example, a department may require no certificate or a simplified one. Ask the building department.
No. It is the amount of added glass that escapes the total and west-facing area limits. Added windows still meet the U-factor and SHGC values.
Explore CF1R: Certificate of Compliance
- CF1R-NCB-01-E: The Prescriptive Certificate for New Homes and Large Additions
- CF1R Prescriptive vs Performance Report: What Is the Difference?
- What Is a CF1R Certificate of Compliance?
- How to Read ECC Measures on a CF1R
- How to Read the Mandatory Measures on a CF1R
View all CF1R: Certificate of Compliance guides → · Forms and Certificates · Title 24 guide