§110.6 · Fenestration mandatory measures

# §110.6: Fenestration mandatory measures

What it requires

Every window, skylight, and door installed on a Title 24 residential project must:

• Carry an NFRC label with U-factor and SHGC values, or use the §110.6 default values (which are intentionally pessimistic so the labeled product is almost always better).
• Meet the §110.6 unit-level air-leakage limit, 0.3 cfm per square foot for operable windows, 0.3 cfm per square foot for sliding doors, 0.5 cfm per square foot for hinged doors.
• Have permanent labels showing certification, these are what the AHJ field inspector checks at rough-in and final.

When it applies

Every fenestration unit on every Title 24 project. There is no carve-out.

How we use it

The Confirm step extracts window U-factor and SHGC from your plan's window schedule and feeds them into the model. If the schedule shows non-NFRC products or doesn't list ratings, we fall back to the §110.6 defaults, which typically fails the prescriptive requirements in §150.1(c), forcing a performance-path or a window upgrade.

Common gotchas

• "Generic" windows on the schedule with no manufacturer / model, defaults apply, prescriptive often fails.
• Skylights that meet U-factor but miss SHGC, the SHGC value flips the §150.1(c) trade-off math in hot climate zones.
• Sliding doors counted as windows in the schedule, the §110.6 air-leakage limit is different for each category.