Does a bathroom need a vacancy sensor?

At least one luminaire must be controlled by an occupancy or vacancy sensor with automatic-off, under §150.0(k)2E. Any other bathroom lights can be on ordinary switches.

How many cfm does a bathroom fan need?

At least 50 cfm if it runs on demand, or 20 cfm if it runs continuously, from Tables 150.0-E and 150.0-F. The installer confirms the delivered airflow.

Do bathroom lights need a dimmer?

No. The dimming rule in §150.0(k)2F covers habitable spaces, and the code’s definition of habitable space excludes bathrooms.

Does replacing a toilet or vanity need Title 24?

No compliance report is needed for either. New faucets must be products certified under the appliance regulations, which §110.1 applies.

Does a Bathroom Remodel Need Title 24?

Only where it changes something regulated. New light fittings must meet §150.0(k), including at least one luminaire on an occupancy or vacancy sensor, and a new or altered exhaust fan must meet §150.0(o)1G; new tile, a vanity, a toilet or a tub on their own need no energy compliance report.

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The bathroom in the code’s terms

Section 100.1 defines a bathroom as a room or area containing a sink used for personal hygiene, a toilet, a shower or a tub, so a powder room counts. The same section leaves bathrooms out of habitable space. That has a practical result: the dimmer rule written for kitchens, living rooms and bedrooms does not reach the bathroom, which has a control rule of its own.

Lighting: the sensor rule

Under §150.0(k)2E, at least one installed luminaire in a bathroom must be controlled by an occupancy or vacancy sensor that switches it off automatically. Section 110.9(b)4 sets what the sensor must do: turn the lights off or down no more than 20 minutes after the room is vacated, and show a visible signal that it is working or has failed. The room still needs a wall-mounted on and off control, and no other switch on the circuit may bypass the sensor.

The fittings follow the rules that apply everywhere in the home. New luminaires and lamps are JA8-certified, and a replacement bath bar may be a screw-base fitting with a JA8 lamp as long as it is not a recessed downlight. Lighting built into a vanity mirror or an exhaust fan is exempt from JA8, but a light in an exhaust fan must be switched independently of the fan. A recessed light over the shower is a recessed downlight like any other: no screw base, airtight, and any replaceable lamp marked for elevated temperature. Product detail is on JA8 lighting.

The exhaust fan

Section 150.0(o)1G requires local mechanical exhaust in every bathroom, in one of two forms:

demand-controlled, at least 50 cfm, with an occupant on and off control or an automatic control that does not stop the occupant turning it on
continuous, at least 20 cfm in every hour of operation, with a manual on and off control

The fan is rated for airflow and sound under ASHRAE 62.2, and the compliance manual gives the limits as 3 sones for a demand-controlled fan and 1 sone for a continuous one. The installer then confirms the delivered airflow, either by measuring it or by building to Table 150.0-H: no more than 25 feet of duct and three elbows, with at least a 4-inch duct for a 50 cfm fan or a 5-inch duct for 80 cfm.

In an existing home, §150.2(b)1Mii applies these rules to an altered bathroom exhaust system, and any new or replacement fan carries the airflow and sound ratings. One case differs. If the bathroom fan is also the home’s whole-dwelling ventilation fan and an earlier permit required that ventilation airflow, the replacement must deliver it, confirmed by an ECC-Rater. If no earlier permit required it, there is no airflow target.

CALGreen, Part 11 of Title 24, adds its own rule for new homes and for additions or alterations that increase conditioned area, volume or size: an ENERGY STAR fan ducted outdoors and, unless it is part of the whole-house ventilation, controlled by a humidity control.

Water heating

A bathroom project often brings a new water heater. That is a separate alteration under §150.2(b)1H, with its own list of allowed equipment and its own pipe insulation rule, set out on Title 24 water heater requirements.

When no forms are needed

New tile, a vanity, a toilet, a tub or a shower pan, with the existing light fittings and fan left in place, alter nothing the Energy Code documents. The compliance manual’s own example is a remodel limited to new faucets and bathroom lighting: it is an alteration, but only §110.1, for the faucets, and §150.0(k), for the lights, apply. New lighting is recorded by the installer on the CF2R-LTG-01-E and needs no ECC verification. A Certificate of Compliance comes in when the work reaches the envelope or the mechanical systems, such as a new window over the tub (see do new windows need Title 24) or an opened exterior wall (see insulation requirements). The general picture is on does a remodel need Title 24.