This is a follow-up to “Manufacturers Fret over CARB Deadlines for Air Conditioning Systems,” published in the Feb. 24, 2020 issue of The ACHR NEWS.

The California Air Resources Board (CARB) held a public workshop in January to discuss its proposals for reducing high-GWP HFCs from stationary refrigeration and air conditioning equipment. Under regulations passed in 2016, California is committed to reducing HFC emissions by 40 percent below 2013 levels by 2030.

To meet this mandate, CARB is proposing a GWP limit of 750 for all new stationary air conditioning systems (residential and commercial) starting Jan. 1, 2023, and the same GWP limit for new chillers, effective Jan. 1, 2024. On the commercial refrigeration side, there is a proposed GWP limit of 150 for new stationary refrigeration systems containing more than 50 pounds of refrigerant, starting on Jan. 1, 2022.

Since CARB’s public workshop last fall, supermarket owners, industry groups, and commercial refrigeration contractors expressed concern about meeting CARB’s low-GWP requirements in existing facilities. As a result, CARB revised its proposal and is offering new options that are still designed to meet California’s mandate to reduce HFC emissions.



Richie Kaur, Ph.D., an air pollution specialist at CARB, discussed the regulatory impacts for stationary refrigeration, which have evolved over this past year, thanks to the input of stakeholders. The proposal mainly affects retail food facilities, including supermarkets and grocery stores, industrial process refrigeration, and cold storage warehouses.

The original proposal, which has been revised since CARB’s 2018 workshop, stated that stationary refrigeration equipment containing more than 50 pounds of refrigerant needed to have a GWP less than 150 starting Jan. 1, 2022. The way it was written, it would affect all new equipment, whether it was installed in new or existing facilities, or in remodels.

For new facilities, staying under the 150-GWP threshold would not be a problem, said Kaur, because there are many different technologies that meet that criteria. These include transcritical CO2, ammonia CO2 cascade, propane CO2 cascade, microdistributed propane, and HFO-based systems. For existing facilities, this could be an issue, because in the original proposal, there was a capital cost threshold. If equipment was replaced in a store and the capital cost threshold was reached, that would trigger the purchase of a new system.

CARB received a lot of feedback from across the refrigeration industry, and most stakeholders said that while it was feasible to reach the 150-GWP threshold in new construction and remodels, there were challenges to accomplishing this in existing facilities for the following reasons:

1. It’s expensive, because the current low-GWP refrigerants are not compatible with the existing refrigeration infrastructure;

2. It’s logistically challenging to complete this transformation without shutting down the store; and

3. The capital cost threshold of replacement is hard to judge. When supermarkets replace equipment, they do it on an as-needed basis, so it would be difficult to judge when a store reached the capital cost threshold.

Given that only two percent of facilities in California are new construction or remodels, an alternative method had to be found for existing stores to reduce HFC emissions. As Kaur explained, HFC emissions are made up of three factors: refrigerant charge, the GWP of the refrigerant, and the leak rate. Of these three variables, only the first two can be guaranteed. And while reducing leaks is important, CARB cannot count on leaks being zero. Plus, the refrigerant management program (RMP) is already established to handle leaks.

With these points in mind, end users came up with two options for CARB to consider. The first option involved prescribed retrofits, where systems could be retrofitted to a lower GWP gas (see Figure 1). The second option is called GHGp reduction, or greenhouse gas potential reduction, which leverages both charge and GWP as variables (see Figure 2). CARB then came up with a third option, which is a hybrid (see Figure 3) that combines the merits of the two options suggested by the end users and minimizes some of the implementation-related challenges, said Kaur.



Looking at each option a little more closely, Kaur explained that a prescribed retrofit option would allow existing systems to be retrofitted to refrigerants with GWP < 1,400 — essentially R-448A/R-449A refrigerants — by 2030.

California Air Resources Board
Option 1 for Existing Stores

Prescribed Retrofits to GWP < 1,400

  • Existing systems retrofit to GWP < 1,400 by 2030
  • Certainty of emissions reductions, straightforward implementation
  • Lacks flexibility – potentially every system (above 50 pounds) using high-GWP refrigerants would be affected

Figure 1

“It is straightforward to implement, but it does lack flexibility,” she said. “When we ran the calculations of how many systems would have to do this to come back to the original emissions reductions that we wanted, nearly every single system would have to do it to get us close.”

Kaur said that end users did not like that option and came up with the second option, which would reduce the total potential emissions across all of a company’s stores. Under this scenario, the total charge of all stores would be multiplied by the GWP of those refrigerants and that would total a company’s potential emissions — that is, if all the refrigerant leaked out. According to end users, they could reduce that GHGp by 55 percent below their 2018 levels by 2030.

California Air Resources Board
Option 2 for Existing Stores

Greenhouse Gas Emission Potential (GHGp) Reduction

  • GHGp = σ(Charge × GWP)
  • Reduce GHGp by ~ 55% below 2018 baseline by 2030
  • Flexible – don’t have to convert / retrofit every single store/system
  • Credit for charge and GWP reduction

Credit for charge and GWP reduction

  • Tracking and reporting each company’s baseline (sales, transfers etc.)
  • Charge reduction – verification is difficult, needs additional recordkeeping / reporting
  • No credit for “nominal” charge reduction; must accompany significant changes

Figure 2

“I’ll remind you that the SB 1383 goal is 40 percent below 2013 levels by 2030, but that boils down to roughly 50 percent below present levels, so this is aligned with that,” said Kaur. “The great thing about this is that it’s a company target — it’s not a system target or even a store target. It’s really a fleet standard for supermarkets in California. And it’s flexible, because if you do more in some stores, you don’t have to do as much in some other stores.”

CARB does see some implementation challenges associated with the second option, noted Kaur. That’s because it is a relative reduction target — it’s 1 percent below a company’s baseline in 2018. That means that for the next eight to 10 years, the company and CARB have to manage and track the baselines, making sure that sales and transfers of stores are documented, so that the responsibility travels with the asset or the store.

“The second aspect is that charge reduction is a little bit harder to verify,” she said. “This will need additional recordkeeping and reporting, because we definitely don’t want this to be a loophole. No credit for nominal charge reduction — we would like to see significant charge reductions for your GHGp to actually go down.”

Because of these concerns, CARB came up with a third option, or hybrid option, which calculates the store’s average GWP by dividing the GHGp by the total pounds of refrigerant. For example, for stores that mainly use R-404A, the average GWP will be closer to 4,000, while in stores that mainly use R-448A/R-449A, the average GWP will be closer to 1,400.

California Air Resources Board
Option 3 for Existing Stores

Weighted-Average GWP Reduction

  • Weighted-Average GWP = Σ(charge X GWP) / Σ charge
  • Target: Weighted GWP of each company < 1,400 by 2030
  • Fixed target, no need for tracking company baselines
  • Fixed target but still per-company, not per system
  • Flexible – don’t have to convert / retrofit every store or system
  • Gives credit for new low-GWP stores
  • Rewards conversion to lower and low-GWP (complete or “modular”)

Figure 3

“There are several reasons why we’re doing this,” said Kaur. “One, it lets us talk in terms of GWP. All of our other rules and goals are characterized in GWP terms, because that’s what’s important about HFCs. Two, it sets an industry standard in California that by 2030, everybody’s below 1,400 GWP. The benefit, again, is that it’s a fixed target — it’s not a relative reduction target, so you don’t have to get a percent below something by someone. With this, everybody has to achieve the same number by the year 2030.”

“The benefit of the two compliance pathways for existing stores is the flexibility to plan these transitions over the next eight to 10 years. And it prepares this sector for a future HFC phasedown or a sales ban.”
— Richie Kaur
Air pollution specialist CARB

She added that this option is also relatively straightforward to implement and that it is still a company target, not a per system or a per store target. That means, like the second option, it is possible to invest in retrofits in some stores without having to touch other stores. It also rewards conversion to lower GWP technologies in existing stores because the weighted average GWP goes down.

Based on these options, CARB is now proposing that new equipment in newly constructed facility on major remodels has to use refrigerants that have a GWP less than 150. For existing retail food facilities — primarily supermarkets and grocery stores — there are two compliance pathways: 1) the weighted average GWP option, and 2) the GHGp option that the stakeholders suggested.

“The benefits of the two compliance pathways for existing stores is the flexibility to plan these transitions over the next eight to 10 years,” said Kaur. “And it prepares this sector for a future HFC phasedown or a sales ban.”



The CARB draft regulatory text keeps the original deadlines, so non-residential refrigeration systems containing more than 50 pounds of refrigerant per system are prohibited from using refrigerants with GWP of 150 or greater starting in 2022. There is an updated definition for new refrigeration equipment, which is now defined as any refrigeration equipment that is first installed using new or used components or a combination of new and used components in the following:

A) New construction; or

B) In an existing facility not previously used for retail, food, commercial, cold storage, or industrial refrigeration; or

C) In an existing facility, replacement of 75 percent or more of compressors, condensers, and connected evaporator models.

For existing retail food facilities, the draft regulatory text separates companies into two categories — those that operate more than 20 stores and those that operate less than that (see Figure 4). For companies with 20 or more stores, there is an additional step in 2026 in which they have to show they are halfway to meeting their goal. As Kaur noted, CARB is asking this group to attain a company-wide average GWP below 2,500 — or a 25 percent reduction in GHGp if GHGp is the chosen option — by 2026, with the final goal still being below 1,400 GWP or 55 percent below baseline for GHGp by 2030.

California Air Resources Board
Requirements for Existing Retail Food Facilities

Paragraph 95374. Table 4: Compliance Requirements for Companies with Retail Food Facilities.

Retail Food Facilities Requirement Effective Date
Companies owning or operating 20 or more retail food facilities Attain a company-wide weighted-average GWP of 2,500 or a 25% reduction in GHGp below 2018 levels January 1, 2026
Attain a company-wide weighted-average GWP of 1,400 or a 55% reduction in GHGp below 2018 levels January 1, 2030
Companies owning or operating fewer than 20 retail food facilities Attain a company-wide weighted-average GWP of 1,400 or a 55% reduction in GHGp below 2018 levels January 1, 2030

Weighted-average GWP and GHGp calculated based on refrigeration systems > 50 pounds of refrigerant only.

Figure 4

“Now any company, large or small, has to get to the same point by 2030,” said Kaur. “The ultimate goal is still 2030. The progress step is missing for the small companies, because we want to give the independent owners/operators a little bit more time to plan this, but nobody gets an extension — everybody has the same final date. Another thing to note is that these calculations have only been done for systems greater than 50 pounds.”

Kaur finished by noting that CARB was still looking for industry input on three issues: First, whether the definition for new refrigeration equipment adequately covers remodels; second, whether the existing equipment labels meet the requirements; and third, for existing retail facilities, whether additional reporting requirements should be considered to verify charge reductions. Kaur said that the regulatory language should be finalized within the next few months.