Bathrooms: ≥ 3 sqft openable window (half openable) OR mechanical local exhaust per M1505
2025 RCNYS §R325.2 Bathroom ventilationDescription
Bathrooms, water closet compartments, and similar rooms must have either at least 3 sqft of glazing area (half of which is openable) OR a local mechanical exhaust system per M1505 that discharges directly to the outdoors. Indoor air quality can NOT rely on a kitchen-style hood — bathroom exhaust must vent out, not recirculate.
Why this exists
The 3 sqft / half-openable rule is met by a 24×18 in awning window. In windowless powder baths, M1505 sets the bath exhaust at 50 cfm intermittent or 20 cfm continuous. Architects should specify ENERGY STAR fans (quieter, more efficient) on the bath spec sheet.
Measurements
| Property | Operator | Value | Unit | Note |
|---|---|---|---|---|
glazingMin | min | 3 | sqft | Minimum bathroom glazing area |
openableFraction | min | 0.5 | fraction | Fraction of glazing that must be openable |
Categories
Applies to
- Jurisdiction: New York State
Source
Solver enforcement
Browsable only — the solver does not currently enforce this directive (no spec-level data to check against). This entry exists so the architect personas can cite it in conversation and the user can read what the rule says.
Related directives
- Natural light in habitable rooms · IRC R303.1
- Carbon monoxide alarms in sleeping areas · IRC R315
- Garage HVAC duct prohibition · IRC R302.5.2
- Natural ventilation in habitable rooms · IRC R303.1 (vent)
- Bathroom ventilation · IRC R303.3
Last reviewed 2026-05-15.