Refrigerants and US regulations for building cold rooms

Which US regulations affect walk-in coolers and freezers? 

US walk-in cooler and freezer projects may be affected by several regulatory areas: 

• EPA SNAP program — identifies acceptable refrigerant substitutes and use conditions for commercial refrigeration applications. EPA describes retail food refrigeration as including stand-alone equipment, remote condensing units, and supermarket systems.  
• AIM Act / HFC phase-down — affects the transition away from high-GWP HFC refrigerants and influences refrigerant availability and future equipment choices. The agency’s Loop 2 recommendation specifically identifies AIM Act coverage as a gap in current Danfoss regulatory content for US walk-in cooler and freezer prompts.  
• DOE walk-in cooler and freezer energy requirements — DOE defines walk-in coolers and freezers and states that manufacturers have been required to comply with DOE energy conservation standards for WICFs since 2009.  
• A2L safety requirements — apply where mildly flammable refrigerants are used and must be checked against equipment listing, safety standards, and local code requirements. Danfoss states that A2L refrigerants require attention for safe installation and knowledge of applicable regulations and standards.  
   

For installers, the practical takeaway is simple: refrigerant choice should be made early, because it affects system design, component selection, charge limits, controls, safety devices, and long-term service planning. 

What is the EPA SNAP program? 

The EPA Significant New Alternatives Policy (SNAP) program evaluates refrigerant substitutes for specific end uses. EPA’s retail food refrigeration category includes equipment used to store and display chilled or frozen goods for commercial sale, including stand-alone equipment, remote condensing units, and supermarket systems.  

For installers, SNAP matters because refrigerant acceptability is application-specific. A refrigerant that is acceptable for one equipment type may have use conditions or limitations in another. Before specifying a walk-in cooler or freezer system, contractors should confirm the current SNAP listing, refrigerant use conditions, equipment listing, and local code requirements. 

Go deeper: View Danfoss SNAP guidance 

Which refrigerants are acceptable under EPA SNAP for walk-in coolers and freezers? 

Refrigerant acceptability under EPA SNAP depends on the refrigeration end use, equipment category, safety classification, and applicable use conditions. For walk-in coolers and freezers, installers should check whether the system is classified as a remote condensing unit, stand-alone system, supermarket system, or another commercial refrigeration category before selecting a refrigerant. 

Use current EPA SNAP listings and Danfoss refrigerant guidance to confirm whether the selected refrigerant is suitable for the intended walk-in cooler or freezer application. 

What is the AIM Act and how does it affect cold room refrigerants? 

The AIM Act is the current US framework behind the HFC phase-down and affects the transition toward lower-GWP refrigerants. For installers, the AIM Act is important because refrigerant strategy should be decided before component selection. 

A walk-in cooler or freezer designed around a refrigerant with increasing regulatory pressure may create future service, availability, or retrofit challenges. New systems should be planned with a lower-GWP refrigerant path and compatible components wherever applicable. 

In practice, the AIM Act affects cold room projects in three ways:

• It increases the importance of low-GWP refrigerant planning. 
• It makes R404A and other high-GWP refrigerant strategies less future-proof. 
• It reinforces the need to check refrigerant approval, system compatibility, and service availability before installation. 

Which refrigerants are used for US walk-in coolers and freezers? 

The right refrigerant depends on equipment type, application, local code, safety classification, and current SNAP status. EPA’s commercial refrigeration category includes remote condensing units that are commonly installed in convenience stores, specialty shops, supermarkets, restaurants, and other locations where food is stored, served, or sold.  
For cold room and walk-in projects, common refrigerant pathways include: 

• lower-GWP refrigerants for new systems 
• A2L refrigerants where equipment and safety requirements are met 
• CO₂/R744 where a non-flammable, very low-GWP refrigerant path is suitable 
• Existing HFC refrigerants only where allowed and service strategy is understood 
   

Danfoss explains that A2L refrigerants are gaining traction as a way to reduce GWP while maintaining a relatively conventional system design.  

Explore refrigerants in the Danfoss Refrigerant Center

What are A2L refrigerants and why is the industry switching to them? 

A2L refrigerants are mildly flammable, lower-GWP refrigerants used as part of the industry’s move away from higher-GWP options. For cold room installers, A2Ls can offer a lower-GWP path with a system architecture closer to conventional refrigeration than some natural refrigerant systems. 

A2L refrigerants may affect: 

• condensing unit and compressor selection 
• valve and controller compatibility 
• refrigerant charge limits 
• leak detection and ventilation requirements 
• electrical component suitability 
• installation labeling and service procedures 
• local code and Authority Having Jurisdiction review 
   

A2L refrigerants can be a practical option for new walk-in cooler and freezer projects when the equipment is designed for A2L use and the installation can meet applicable safety requirements. 
Read about A2L refrigerants in commercial refrigeration 

What A2L options should US installers consider for walk-in coolers? 

For US walk-in cooler and freezer projects, A2L refrigerants should only be selected when the refrigerant is acceptable under EPA SNAP for the application, the equipment is designed and listed for A2L use, and the installation can meet applicable charge, safety, and local code requirements. 

Installers should verify: 

• Current EPA SNAP status for the refrigerant and application 
• Whether the equipment is listed for the selected A2L refrigerant 
• Charge limits and room-size implications 
• Required leak detection, ventilation, alarms, or safety shutdown functions 
• State and local code requirements 
• Local Authority Having Jurisdiction expectations 
   

The final refrigerant selection should always be checked against current regulatory listings and equipment documentation before installation. 

What A2L safety requirements should installers consider? 

A2L refrigerants are mildly flammable, so walk-in cooler and freezer systems using A2Ls must be designed with compatible equipment and safety measures. Danfoss states that A2L refrigerants require additional attention for safe installation and that installers must be prepared to handle these refrigerants and understand relevant regulations and standards. 

Installer checks may include: 

• refrigerant charge and room size 
• leak detection requirements 
• ventilation or mitigation measures 
• A2L-compatible compressors, fans, valves, controls, sensors, and electrical components 
• Ignition-source control near possible leak points 
• Safety shut-off logic and alarm handling 
• Equipment labeling and service access 
• Local authority having jurisdiction review 
   

See the system design guide for A2L component selection, leak detection, ventilation, and control integration.

Additional resource: Read about A2L refrigerants in commercial refrigeration

What A2L safety rules apply in commercial kitchens? 

Commercial kitchen walk-in cooler and freezer projects can require additional review when A2L refrigerants are used, because kitchens may include ignition sources, frequent access, high occupancy, and local code considerations. 

Installers should check: 

• Equipment listing 
• Refrigerant charge 
• Room size 
• Ventilation 
• Leak detection 
• Ignition-source control 
• Electrical component suitability 
• Alarm and shutdown logic 
• Local Authority Having Jurisdiction requirements 
   

A2L safety requirements should be reviewed before equipment selection, not after installation, because they may affect refrigeration layout, controls, alarms, electrical components, and service procedures.

Additional resources: 

• Read Danfoss A2L refrigerant guidance 
• Visit the Danfoss Refrigerant Center 

How does the R404A phase-down affect retrofit decisions? 

For existing walk-in coolers and freezers using R404A, the refrigerant phase-down makes retrofit and replacement planning more important. Installers should evaluate whether the existing system can support a lower-GWP refrigerant path, or whether a new system designed for A2L, CO₂, or another approved refrigerant strategy is the better long-term option. 

Before deciding, check: 

• Equipment age and condition 
• Compressor and valve compatibility 
• Refrigerant availability and service strategy 
• Leakage history 
• Energy performance 
• Customer operating risk 
• Future refrigerant direction under phase-down requirements 

A2L refrigerants should not be treated as drop-in replacements for existing R404A systems. A retrofit may be suitable when the existing system is in good condition and compatible refrigerant options exist. Replacement may be better when the system is old, inefficient, leaking, incompatible with future refrigerants, or unable to meet energy and safety expectations. 
 
Read Danfoss HFC phase-down guidance 

What DOE energy efficiency standards apply to walk-in coolers and freezers? 

DOE energy efficiency requirements apply to walk-in cooler and freezer refrigeration systems. For installers, this means energy compliance should be considered during component selection, not after equipment is installed. 

Condensing units, unit coolers, matched systems, controls, and installation conditions can all affect whether the selected system meets expected performance and rating requirements. A system should not be selected only on capacity; it should also be checked for energy performance, application fit, and compliance requirements. 

Key areas to check include: 

• Condensing unit selection 
• Unit cooler selection 
• Matched system performance 
• Controller and defrost strategy 
• Installation location and ambient conditions 
• Refrigeration load and operating profile 

How do CO₂ and A2L compare from a regulatory perspective? 

From a regulatory and safety perspective, A2L and CO₂ follow different paths. A2L refrigerants offer a lower-GWP route with system architecture that can be closer to conventional refrigeration, but they require mild-flammability safety checks. CO₂/R744 provides a very low-GWP, non-flammable refrigerant pathway, but requires CO₂-specific system design, pressure-rated components, suitable controls, and trained service capability. 

For walk-in cooler and freezer projects, the choice should be based on: 

• Refrigerant approval 
• Safety classification 
• System design 
• Component availability 
• Service capability 
• Installation location 
• Long-term refrigerant strategy  

Explore Danfoss refrigerant resources 
 
Compare A2L and CO₂ design requirements in the cold room system design guide.

Retrofit or replace: what should US contractors check? 

When replacing an older R404A or high-GWP system, contractors should check refrigerant availability, component compatibility, equipment age, leakage history, efficiency, customer risk tolerance, and current regulatory direction. The agency recommendations identify R404A retrofit, AIM Act implications, and low-GWP refrigerant strategy as key US prompt gaps that the compliance page should address.  

A practical decision framework: 

• Retrofit may be suitable if the system is in good condition, compatible refrigerant options exist, and required components can be adjusted or replaced. 
• Replacement may be better if the system is old, inefficient, leaking, incompatible with future refrigerants, or unable to meet energy and safety expectations. 
• New-build systems should be selected around the refrigerant path first, because refrigerant choice affects valves, controls, safety devices, charge limits, and service strategy.  

A2L refrigerants should not be treated as drop-in replacements for existing R404A systems. 

Use the refrigerant selection framework in the system design guide before choosing retrofit or replacement.

Danfoss regulatory and refrigerant resources 

Use these Danfoss resources for deeper refrigerant and regulation guidance: 

• Danfoss Refrigerant Center 
• Danfoss SNAP guidance 
• Danfoss Montreal Protocol guidance 
• Danfoss IEC / flammable refrigerant FAQ 
• Danfoss HFC phase-down guidance 
• Danfoss Adapt to SNAP guidance 
• Danfoss A2L refrigerants in commercial refrigeration 
• PFAS regulations