An ECC rater is the independent tester who checks your ADU's energy features in the field and signs the CF3R forms. It is the same role that used to be called a HERS rater. A typical ductless mini-split ADU needs three to five rater visits.
Why did HERS become ECC?
The California Energy Commission (CEC) says its Energy Code Compliance (ECC) Program "replaces the HERS Program." For the 2025 Energy Code, the field testing rules moved from Title 20 into the administrative part of Title 24. The CEC says prior field verification services "will continue without disruption."
So "HERS rater," "HERS test," "ECC rater" and "ECC verification" all describe the same work on a residential project. Many raters still advertise under the HERS name.
ECC-Raters are certified by ECC-Providers that the CEC approves. The CEC's provider page lists CHEERS, approved on November 12, 2025.
What does an ECC rater test on a ductless mini-split ADU?
Your CF1R lists the exact items. The CEC's 2025 ADU FAQ names the common ones for mini-splits and multi-splits:
- Refrigerant charge. Required for heat pumps in all climate zones (Section 150.1(c)7A).
- Verified SEER2 (cooling efficiency rating).
- Verified HSPF2 (heating efficiency rating).
- Verified heat pump rated heating capacity.
- Minimum airflow.
- Duct leakage and fan efficacy (watts per CFM), but only for ducted systems.
Other items that often appear on ADU reports:
- Kitchen range hood. The CEC says vented range hoods in ADUs must have their certification, airflow and sone rating verified by an ECC rater.
- Whole-house ventilation fan. New dwellings must meet the ventilation rules in Section 150.0(o). The rater checks the fan.
- Quality insulation installation (QII), when it applies. The rater inspects insulation and air sealing before the drywall goes on.
Does my ADU need QII?
- ADU additions of 700 square feet or less (attached ADUs, garage conversions): the prescriptive QII requirement does not apply. If the report takes QII as a credit, the rater must still verify it.
- Additions over 700 square feet: QII applies to the addition.
- New detached ADUs: these follow the rules for a new home.
Check the ECC section of your CF1R. If QII is listed, plan for it before drywall.
Why does the refrigerant check need its own visit?
Mini-splits are usually charged by weight. The installer weighs in refrigerant based on the line-set length.
The CEC's refrigerant charge verification form says that for the weigh-in method, the "ECC Rater Must Observe and Confirm All Data Collected." It also notes mini-splits may only be chargeable by weigh-in. In practice, the rater has to be on site the day the installer charges the system.
The same form says systems verified by weigh-in are not eligible for group sampling. Each system gets checked.
How many visits does a typical ADU need?
A common pattern for a new detached ADU with a ductless mini-split:
| Visit | What happens | When |
|---|---|---|
| 1-3 | QII inspections (if listed) | Framing and insulation done, before drywall |
| 4 | Refrigerant weigh-in observation | Mini-split install day |
| 5 | Final: ventilation fan, kitchen hood, heat pump ratings and capacity | Near final inspection |
Best case is about three trips. An ADU addition under 700 square feet with no QII may need only two: the weigh-in and the final. A failed test adds a trip.
How can I need fewer rater trips?
- Read the ECC list on your CF1R early. Send it to the rater when you ask for a quote.
- Book QII before drywall. Once the walls are closed, QII cannot be inspected.
- Line up the weigh-in. Tell the rater the install date, or ask the HVAC contractor to schedule it with them directly.
- Group the final items. Fans, hood and equipment ratings fit in one visit if everything is installed and running.
- Have the CF2Rs signed first. The CEC manual says the rater cannot sign a CF3R unless the installer's CF2R is registered and signed.
- Have the model numbers ready. The rater checks ratings against certified directories, so keep the equipment and hood model numbers on hand.
- Two ADUs on one lot? Ask whether visits can be shared. Each unit is still tested.
What does an ECC rater cost?
Prices vary by rater and region. These are published examples, not quotes:
| Item | Published price | Source |
|---|---|---|
| First test on a trip | $250 | energyguru.com |
| Each extra test, same trip | $50 | energyguru.com |
| QII (three trips) | $350 | energyguru.com |
| Extra trip | $85 | energyguru.com |
| QII, California market range | $250-$500 | ereinspections.com |
| CHEERS registry fee per new-construction project (paid by the rater) | $45 | cheers.org |
Get two quotes using your CF1R's ECC list. Ask whether the weigh-in visit and retests are included.
Who hires the rater?
Usually the builder or owner-builder. The CEC manual says the builder must arrange a certified ECC-Rater when the CF1R calls for ECC verification. The rater must be independent of the builder or general contractor.
To find raters near you, CHEERS has a "Find a Pro" search on cheers.org.
Need your ADU's CF1R first? See our flat prices.
Frequently asked questions
Is an ECC rater the same as a HERS rater?
Yes. The California Energy Commission's Energy Code Compliance (ECC) Program replaces the HERS Program for field verification and testing. The job is the same; the name changed with the 2025 Energy Code.
What does an ECC rater test on a ductless mini-split ADU?
Common items are refrigerant charge, verified SEER2 and HSPF2 ratings, verified heating capacity, ventilation fan airflow, and the kitchen hood's certified ratings. Your CF1R lists exactly which ones your project needs. Ducted systems add duct leakage and fan watt draw tests.
How many rater visits does an ADU need?
Often three to five. Quality insulation inspection (QII), when it applies, needs visits before drywall. A mini-split charged by weight needs the rater on site to watch the charge. Fans, hood and equipment ratings can usually be checked in one final visit.
Can I hire the rater myself?
Yes. The rater must be independent of the builder or general contractor and certified by a CEC-approved ECC-Provider. Today that provider is CHEERS.
What happens if a test fails?
The failure is recorded in the registry. The contractor fixes the problem and the rater tests again, which usually means another trip.
Related
Sources
- energy.ca.gov/programs-and-topics/programs/energy-code-compliance-program
- energy.ca.gov/programs-and-topics/programs/energy-code-compliance-program/ecc-providers-energy-code-compliance
- energy.ca.gov/programs-and-topics/programs/building-energy-efficiency-standards/energy-code-support-center-6/2025
- energy.ca.gov/filebrowser/download/8634?fid=8634
- energy.ca.gov/filebrowser/download/8641?fid=8641
- energy.ca.gov/filebrowser/download/8282?fid=8370
- energyguru.com/pricing.html
- ereinspections.com/guides/hers-test-cost
- cheers.org/pricing/
- cheers.org/