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This article discusses the verification summary table document in-depth. The PDF is attached to this article and can be downloaded at the bottom of the page.
This article goes over the triggers and test targets for 2016 CF-3R Alteration forms. An alteration is a remodel or change-out of the existing HVAC (home ventilation and air conditioning) system.
Note: This guide focuses on how forms trigger on Prescriptive CF-1R projects. In Performance-based CF-1R projects, it is possible to specifically require any of these tests even if the scope of work is not met.
For instance, you may have a CF-2R form for refrigerant charge even though the scope of work doesn't meet the requirements. The performance file gets additional compliance rating for triggering verification; it may be a necessary test in order to make the 0%> compliance rating margin. Consult your Title-24 preparer if you're not sure why a test is appearing.
To use the above table, you must know the scope of work in regard to the mechanical system for your Alteration project. You also need to know what Climate Zone the dwelling is in. Use the CEC's Climate Zone by Zip Code breakdown to determine what the dwelling's Climate Zone is, you can also refer to the CF1R for the applicable climate zone for the project.
There are four main tests: Duct Leakage (MCH-20), Refrigerant Charge (MCH-25), Airflow (MCH-23), and Fan Watt Draw/Efficiency (MCH-22). These tests are all HERS-Verified, meaning once submitted, a CF-3R version of the form will be generated for a HERS Rater to verify and complete.
It's important to determine which forms are needed so test results can be taken at the time of installation, if any. If there are no HERS-verified measures, no CF-3Rs will be generated and hiring a Rater would not be necessary.
Scope of Work Examples:
Example 1 - Entirely New System (equipment and ducts)
You're replacing the existing HVAC system with a new furnace, condenser, and evaporator coil in an existing home. At least 75% of the ducting has been replaced and any remaining components of the previous ducting are accessible and can be sealed. The building is located on the coast in Climate Zone 4.
This scope of work would qualify as a an Entirely New System. The duct leakage must be less than or equal to 5%. The airflow test must produce greater than or equal to 350 CFM per ton. The fan efficacy watt draw test must be less than or equal to .58 watts per CFM produced.
Since this is Climate Zone 4, the refrigerant charge test is not required. A performance-based CF-1R may still require the test. If this was Climate Zone 12 again, we would have to verify charge.
Example 2 - New Duct System Only
At least 75% of the ducting was replaced while the retained portions are accessible and can be sealed. The equipment has not been altered in any way. The climate zone does not matter in this scenario. The duct leakage must be less than or equal to 5%. The airflow test must produce greater than or equal to 350 CFM per ton. The fan efficacy watt draw test must be less than or equal to .58 watts per CFM produced. Refrigerant charge is not triggered since no refrigerant containing component was altered.
Example 3 - Altered Duct System
45 ft. of new ducting was installed, but only about 50% of the ducting is new with the retained ducting being accessible.
In this case, you would have an Altered Duct System, where less than 75% of the total ducting is new, but at least 40 ft of ducting was replaced or added. This will require duct leakage to be less than or equal to 15%. If 75% or more of the ducting was replaced or considered new, this would be considered a New Duct System and would require a 5% duct leakage test instead.
Example 4 - Furnace Only
You're replacing the furnace in an existing home. There is no cooling system present. You've replaced about 10 feet of ducting (less than 75% of the total).
This would be considered a Furnace/FAU Change-Out. To verify the work of this job, you should only need to do a Duct Leakage test (MCH-20) to make sure the ducts are leaking less than or equal to15%.
If the system cannot meet 15% duct leakage, duct leakage to outside ≤10% or use of
the Seal All Accessible Leaks protocol with a Smoke Test may be used to pass the test.
Example 5 - Furnace/FAU and Condenser
You're replacing both the condenser and the furnace in an existing home. About 30 feet of ducting was altered (less than 75% of the total). The home is in Sacramento - Climate Zone 12.
This would be considered a Furnace/FAU Change-Out as well as a Condenser or Coil Change-Out. A duct leakage test at less than or equal to 15% would be required. Since this is within Climate Zones 2 & 8-15, a Refrigerant Charge and Airflow test would be required. The refrigerant charge airflow test requires greater than or equal to 300 CFM/ton. If 300 cfm cannot be achieved, the installer is required to perform airflow remediation as per RA126.96.36.199.5.1.
This is not considered a New System because the duct system does not qualify as "new." A duct system is new when 75% of the total ducting is brand-new and any retained portions of the ducting are accessible and can be sealed.
Example 6 - Ductless Mini-Split
You're adding a ductless mini-split to a bedroom that gets poor air conditioning. Refrigerant charge lines run outside to a condenser which powers the mini-split head. There are no ducts in this zone. The Climate Zone is 4.
This would not require any CF-2R tests. Normally an altered/added system with refrigerant charge would require an airflow and charge test, but since we're in a coastal climate, it isn't required outright (no ducting means these tests can't be run, too). This would also normally require a duct leakage test to 15%, but since it's a ductless system, there are no ducts to test. This would be considered an exception to verification.
Exceptions To HERS Verification:
Duct Leakage Exceptions:
- The system is not ducted (e.g., ductless mini‐split, wall units, etc.).
- There are less than 40 feet of ducts total in any space including plenums and the FAU.
- The ducts are constructed, insulated, or sealed with asbestos.
- The system was previously tested by a HERS Rater and that HERS Verification Certificate is available. Exception does not apply if more than 40 feet of ducts have been added or replaced since the original verification. It does apply to systems passed as part of a sample group.
Refrigerant Charge Exceptions:
- Air conditioning (cooling) not installed or determined to be non‐operational by the local code enforcement agency.
- New package units with factory charge certified by installer on the CF2R‐MCH‐25. Minimum airflow must still be verified for ducted systems.
System Airflow & Fan Efficacy Exceptions:
- The system is not ducted.
- The system does not have air conditioning (cooling).
- VRF (variable refrigerant flow) systems driving multiple (2 or more) indoor coils.
- The Return Ducting test (MCH-28) overrides the MCH-23/22 and makes these tests unnecessary.