Guide

The HERS Inspection After HVAC Installation What actually happens once the new system is in

Reviewed by the Brewer HVAC technical team • Updated August 2026

After your new system is installed, one step stands between the job and final sign-off: the HERS inspection. A certified third-party rater visits to verify the work meets California Title 24 standards. This guide walks through what that visit looks like, what the rater measures, who does it, and how to prepare. We serve Grass Valley, Nevada City, Penn Valley, Auburn, Colfax, Truckee, and Tahoe City, where most changeouts trigger this requirement.

Why a HERS inspection is required after HVAC work

HERS stands for Home Energy Rating System. In California, Title 24 requires independent verification on most HVAC changeouts to confirm the installed system performs as designed. The contractor who installs the equipment cannot self-certify the energy measures. A separate certified rater checks the work, which keeps the verification honest.

The inspection is tied to your building permit. The permit will not close, and the job is not truly finished, until the HERS results are registered and passed. So the inspection is not optional paperwork. It is the gate between a system that is physically installed and a system that is legally complete. In the Sierra foothills, where heating and cooling loads swing hard between seasons, this verification matters because small duct or charge errors cost real money over a long Nevada County winter.

What the HERS rater actually checks

The rater tests the measures that affect how efficiently your system runs. Which ones apply depends on what was installed, but the common checks are:

Duct leakage: the ducts are pressurized and sealed leakage is measured against the Title 24 limit. Leaky ducts waste conditioned air into attics and crawlspaces.
Refrigerant charge: on AC and heat pump systems, the charge is verified so the unit cools and heats at its rated capacity.
Airflow: the rater confirms the system moves enough air across the coil, often measured in CFM per ton.
Fan watt draw: the electrical draw of the air handler fan is measured to confirm it is not wasting power.

Not every job needs all four. A straightforward furnace swap may only trigger duct testing, while a full AC installation usually triggers several. Your installer knows which measures apply before the work starts.

Who performs the HERS inspection

The inspection is done by a certified HERS rater who is independent from the company that installed your equipment. That independence is the whole point of the program. The rater holds a certification through a state-approved HERS provider and registers the results in a statewide compliance system.

In practice, your HVAC contractor schedules the rater as part of the project. You usually do not have to find one yourself. At Brewer HVAC, we coordinate the rater visit so the testing lines up with the install and the permit timeline, which keeps the job moving instead of stalling at the finish line. We have done this on Nevada County and Placer County homes since 1980, and our NATE-certified technicians install to the standard the rater is going to measure against.

What you need to prepare as a homeowner

The visit is short and you do not need to do much, but a few things help it go smoothly:

Access: the rater needs to reach the indoor and outdoor units, the air handler, and any registers. Clear a path to closets, attics, and the equipment.
Pets and parking: secure pets and leave room for the rater to park near the equipment side of the house.
Run time: the system may need to run during testing, so the home will heat or cool briefly while the rater works.
Timing: most residential HERS visits take under an hour, though larger or multi-system homes take longer.

You do not need to interpret the numbers. The rater handles registration, and your contractor confirms the pass with the building department. If a measure comes in out of range, it gets corrected and retested before sign-off.

What happens during a HERS inspection, step by step

Here is the sequence on a typical Nevada County job once the equipment is installed:

1. Schedule: the rater is booked after the install is complete and the system is running.
2. Visual review: the rater confirms the installed equipment matches what the permit and energy documents specify.
3. Diagnostic testing: duct leakage, refrigerant charge, airflow, and fan watt draw are measured as applicable, using calibrated instruments.
4. Results and registration: passing results are entered into the state registry. A failed measure is corrected and retested, not waved through.
5. Permit close-out: the registered results let the building department finalize the permit.

Done right, the inspection is a quick confirmation that the system you paid for is the system you got. If you want help planning the rebates and financing around a new install, or you have questions about whether your changeout will trigger HERS testing, the answer usually comes down to the equipment and the permit scope. Current rebate and tax credit programs change over time, so check what applies at the time you install. You may qualify for incentives on high-efficiency equipment depending on the programs active then.

Frequently asked

Is a HERS inspection always required after a new HVAC install?

Not always, but it is required on most changeouts in California under Title 24. Whether it applies depends on what was installed, such as new ducts, a new AC, or a heat pump. Your contractor can tell you before the work starts which measures will be tested.

Who pays for the HERS inspection?

The cost is typically folded into your HVAC project. The contractor schedules the certified rater as part of the install, so you usually pay it through the overall job rather than hiring the rater separately.

How long does the HERS inspection take?

Most single-system residential inspections take under an hour. Larger homes, multiple systems, or extensive duct testing can take longer. The rater needs the system running during part of the visit.

What happens if my system fails a HERS test?

A failed measure is corrected and retested before the permit closes. It is not a penalty, it is a checkpoint. If duct leakage or refrigerant charge is out of range, the issue gets fixed and the rater verifies the corrected result.

Can my installer also do the HERS inspection?

No. The HERS rater must be independent from the company that installed the equipment. That separation is what makes the verification credible. Brewer HVAC coordinates a certified third-party rater as part of your project.

Do I need to be home for the HERS inspection?

Someone needs to provide access to the equipment, attic, and registers, and to secure pets. You do not need to take part in the testing itself. The rater handles the diagnostics and registration.