Guide

How HERS Testing Can Delay an HVAC Project And the simple steps that keep yours on schedule

Reviewed by the Brewer HVAC technical team • Updated July 2026

Most homeowners only hear about HERS testing when their new system is already installed and the project stalls waiting on a third-party verifier. In California, HERS testing is a required step on many HVAC changeouts, and skipping the planning around it is one of the most common reasons a job runs long. The good news: the delays are predictable, and almost all of them are avoidable with the right contractor and a little sequencing up front. Here is what HERS testing is, why it holds projects up, and how Brewer keeps yours moving.

What HERS testing actually is

HERS stands for Home Energy Rating System. It is California's framework for independently confirming that certain energy features of your home perform the way the code assumes they do. For HVAC work, that means a certified third-party HERS rater (not your installing contractor) comes out and verifies the measures triggered by your project. Common ones include duct leakage testing, refrigerant charge and airflow verification on air conditioners and heat pumps, and fan watt draw. The rater is independent on purpose. Their sign-off is what lets the building department close out your permit. No passing HERS test on the required measures, no final approval. Understanding that the rater is a separate party from your installer is the first step to understanding why timing matters.

Why HERS testing is required on California HVAC work

California's energy code, Title 24, governs how homes use energy. When you replace a furnace, air conditioner, or heat pump, or make changes to your ductwork, your project often triggers Title 24 compliance measures that have to be field-verified by a HERS rater. The exact measures depend on the scope. A full system changeout, new equipment, or significant duct work generally pulls in more verification than a minor like-for-like swap. The point of the requirement is straightforward: a system can be sized and installed correctly on paper and still leak air, run low on refrigerant, or move the wrong amount of air. HERS testing confirms the install performs in the real home, not just in the load calculation. It protects your comfort, your energy bills, and the value of the equipment you just paid for.

Where the delays actually come from

The delay is rarely the test itself. A HERS test on a residential changeout is usually a short visit. The hold-ups come from everything around it:

The rater is not scheduled early. Independent raters book out, especially in peak heating and cooling seasons. Calling one after the equipment is already in adds days or weeks of waiting.
The system fails on the first visit. Excess duct leakage, an incorrect refrigerant charge, or low airflow means a re-test, and a re-test means a second appointment and a second wait.
Permits and paperwork lag. If the permit, the compliance documents, or the registered HERS forms are not in order, the building department cannot close out the job even after a passing test.
The trades are out of sequence. If insulation, drywall, or other work covers ductwork before testing, access problems can force rework.

Every one of these is a scheduling and coordination problem, not a code problem. That is exactly why the right contractor makes the difference.

How a good contractor prevents the holdup

At Brewer, HERS verification is planned before the first tool comes out, not after. That looks like a few concrete habits. We line up the rater alongside the install so testing happens promptly instead of weeks later. We install to pass the first time: sealing ducts properly, charging the system to spec, and confirming airflow before the rater ever arrives, so a re-test is the exception, not the plan. We keep the permit and compliance paperwork moving in parallel with the physical work. And we sequence the job so ductwork stays accessible until verification is done. Our NATE-certified technicians know what the rater will check because they build to those numbers from the start. A clean first-pass test is the single biggest lever on your timeline, and it comes down to install quality.

What HERS delays mean for Nevada County and foothills homeowners

Timing matters more here than in milder climates. In the Sierra foothills, a furnace that goes down in a Grass Valley or Nevada City cold snap, or an air conditioner that fails during a Penn Valley or Auburn heat wave, is not something you want stretched out by an avoidable re-test. Towns like Colfax, Truckee, and Tahoe City see real temperature swings, and the gap between install and final sign-off is a gap you feel. Local familiarity helps in another way too: a contractor who works with Nevada County and Placer County building departments and with area HERS raters every week knows the local scheduling realities and paperwork expectations. That experience is what turns a multi-week stall into a clean, on-schedule project. See our work on AC installation, heat pumps, and furnace installation.

Planning your project so HERS never slows it down

You do not need to manage the HERS process yourself. You just need to choose a contractor who manages it for you. A few questions to ask before any changeout:

Does my project trigger HERS testing, and which measures? A straight answer up front sets expectations.
When will the rater be scheduled relative to the install? The earlier, the better.
What is your first-pass rate, and how do you handle a re-test if one is needed?
Will you handle the permit and the registered compliance documents?

It is also worth knowing that energy-efficient upgrades like high-efficiency heat pumps may qualify for current rebate or tax-credit programs. These programs change over time, so confirm what is active when you buy rather than assuming a specific amount. If cost is a factor in moving forward, our financing options can help you replace a system without the full upfront expense. The throughline is simple: plan the verification into the project, and HERS testing stops being a delay and becomes just another step that passes on schedule.

Frequently asked

Is HERS testing required for every HVAC replacement in California?

Not every single one, but most changeouts trigger it. Replacing a furnace, air conditioner, or heat pump, or altering ductwork, generally pulls in Title 24 measures that a certified HERS rater has to verify. The exact measures depend on your project's scope. A good contractor will tell you up front whether yours requires testing and which measures apply.

How long does HERS testing add to my project?

The test visit itself is usually short. The time it adds depends almost entirely on scheduling and whether the system passes on the first try. When the rater is booked alongside the install and the system is built to spec, testing fits into the normal timeline. Delays come from late scheduling or a failed first test that forces a re-visit.

Who performs the HERS test, my contractor or someone else?

A certified third-party HERS rater performs it, and they are intentionally independent from your installing contractor. Your contractor coordinates the rater, prepares the system to pass, and handles the permit and compliance paperwork, but the verification itself is done by the separate rater so the result is impartial.

What happens if my system fails the HERS test?

A failure means the issue gets corrected and the affected measure is re-tested. Common causes are excess duct leakage, incorrect refrigerant charge, or low airflow. A re-test means a second appointment and added time, which is why installing to pass the first time is the most important thing a contractor can do for your schedule.

Can I skip HERS testing to save time or money?

No. Without a passing HERS test on the required measures, the building department cannot close out your permit, which leaves your project legally incomplete. Skipping it also means no independent confirmation that your new system performs correctly, which can cost you in comfort and energy bills later. The faster path is to plan the test in, not avoid it.

Does Brewer handle the HERS process for me?

Yes. We plan HERS verification before the install begins, coordinate the certified rater, build the system to pass on the first visit, and manage the permit and compliance documents. As a Carrier Factory Authorized Dealer with NATE-certified technicians serving Nevada County and Placer County, we treat clean, on-schedule HERS sign-off as part of doing the job right.