Commercial HVAC-Only Tenant Improvement: Title 24 Requirements

Replace, extend or move: three different outcomes

Replacing a unit, air handler, condenser or coil is an alteration under Section 141.0(b)2C and 2E. The new part meets the Section 140.4 rule for that component, and a thermostat that is not demand responsive is replaced with one that is. Expanding an existing system to serve the new layout, or moving existing equipment within the building, is covered by Exceptions 1 and 2 to Section 141.0(b): the existing system need not meet Sections 110.0 to 120.9 or 140.4 to 140.5.

Numbers that decide the scope

• An air handler with design cooling capacity over 33,000 Btu per hour needs an economizer under Section 140.4(e). Replacement systems that are not single-package air-cooled units and are under 54,000 Btu per hour are excepted.
• A new single-zone packaged rooftop unit under 65,000 Btu per hour follows Table 141.0-E-1 for retail, office, school and library space, or the performance approach.
• Ducts that are at least 75 percent new material are leakage tested. Extending a constant-volume single-zone system under 5,000 square feet can require sealing to 15 percent of airflow, confirmed by test.
• Adding VAV boxes to existing electric reheat may raise reheat capacity by no more than 20 percent per permit.

Repairs and the fault detection exclusion

A repair is not an alteration if it does not raise the component's existing energy use (Section 141.0(c)). Economizer fault detection under Section 120.2(i) does not apply to alterations of space-conditioning systems.

Forms and tests

File NRCC-MCH-E with the permit and have the installer sign NRCI-MCH-E. A certified mechanical acceptance test technician then completes the forms the equipment triggers, such as NRCA-MCH-03-A for single-zone unit controls, NRCA-MCH-04-A for duct leakage and NRCA-MCH-05-A for an economizer. For the replacement rules by equipment type see HVAC replacement and economizers. Moving walls as well? Start with tenant improvements, or send plans to our commercial desk. Lighting changes are on their own page.

Common Title 24 Questions

1. When does a commercial project need Title 24?
2. Does an office tenant improvement need Title 24?
3. Does a restaurant remodel need Title 24?
4. Does a retail tenant improvement need Title 24?
5. What plans are needed for a commercial Title 24 report?
6. What is an NRCC certificate of compliance?

Frequently Asked Questions

If I only move ductwork and diffusers, is that an alteration?

Is a like-for-like rooftop swap a repair?

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