R-448A
Quinary HFC/HFO blend marketed as Honeywell Solstice N40 — A1 safety, GWP 1387 (65% lower than R-404A), ~10°F glide. The dominant R-404A drop-in retrofit refrigerant preserving A1 classification.
Lower toxicity (Occupational Exposure Limit ≥ 400 ppm). No flame propagation in air at standard atmospheric pressure and 60°C. R-134a, R-22, R-410A, R-404A, R-744 (CO2) are A1.
- Flammability
- None (no flame propagation)
- Toxicity
- Lower (OEL ≥ 400 ppm)
Classification per ANSI/ASHRAE Standard 34-2022. See full reference.
Saturation pressure-temperature curve
No PT chart in this build — see manufacturer datasheet. R-448Ahas a published PT chart in its manufacturer's technical datasheet (linked below). The chart has not been transcribed into this site's dataset. For service work, use the manufacturer's published PT chart directly — link below.
- manufacturer-datasheetHoneywell International Inc., Solstice N40 (R-448A) PT Chart (PDF, published technical data sheet).Manufacturer-published PT chart with bubble and dew columns for R-448A (zeotropic HFC/HFO blend).https://prod-edam.honeywell.com/content/dam/honeywell-edam/pmt/oneam/en-us/refrigerants/documents/hon-ess-am-3161690-adm-tds-pt-chart-solstice-n40-a4-en.pdf
- manufacturer-physical-propertiesHoneywell Solstice N40 Physical Properties brochure.https://www.honeywell-refrigerants.com/europe/wp-content/uploads/2019/10/3820_Solstice-N40_web.pdf
At a glance
Chemistry
Lubricant compatibility
POE required. Designed as a lower-GWP replacement for R-404A in commercial refrigeration. Significant glide (~5 K).
Blend composition
- R-3226.0%
- R-12526.0%
- R-1234yf20.0%
- R-134a21.0%
- R-1234ze(E)7.0%
Trade names
- Solstice N40Honeywell
Common applications
- Commercial refrigeration (supermarket cases, walk-in coolers)
- Medium and low-temperature refrigeration
- R-404A retrofit candidate
Properties
- Boiling point (1 atm)-45.9°C / -50.6°F
- Critical point180.9°F at 654 PSIG
- Molar mass86.30 g/mol
- Temperature glide11.5°F
- ODP0
- GWP (AR5, 100-yr)1387
- GWP (AR6, 100-yr)1421
What is R-448A?
R-448A is a quinary blend of five components — R-32 (26%), R-125 (26%), R-134a (21%), R-1234yf (20%), and R-1234ze(E) (7%) by mass [ashrae34]. The unusual five-component composition was engineered by Honeywell as a drop-in retrofit for R-404A commercial refrigeration equipment, balancing several competing requirements: maintain A1 safety class (preserve R-404A equipment compatibility), reduce GWP substantially below R-404A's 3922, match R-404A's pressure and capacity envelope, and preserve POE oil compatibility.
The result is GWP 1387 — a ~65% reduction from R-404A while preserving the A1 safety class that lets existing R-404A equipment accept R-448A without equipment-level redesign [snap]. Honeywell markets R-448A as Solstice N40; it has captured substantial commercial refrigeration retrofit market share through 2017-2026.
Where R-448A is used
- R-404A retrofit for medium and low-temperature commercial refrigeration (walk-in freezers, refrigerated cases, ice machines)
- R-22 medium-temperature commercial refrigeration retrofit
- New equipment installations where A1 classification is required but lower GWP than R-404A is desired
- Supermarket refrigeration retrofit where R-744 transcritical conversion is uneconomical
Regulatory & phase-down status
R-448A's GWP of 1387 is substantially below R-404A's 3922 but above the EU F-Gas 150-GWP threshold for some commercial refrigeration categories and above the EPA AIM Act 700-GWP threshold for residential AC (though R-448A isn't used in residential AC) [aimact][eufgas].
For commercial refrigeration specifically, R-448A's regulatory position depends on the specific end-use. EU F-Gas Regulation revisions through 2024 may tighten thresholds in some categories where R-448A would no longer comply, accelerating the shift to A2L low-GWP alternatives (R-454C, R-455A at GWP 148). For existing R-404A installations needing retrofit through the late 2020s, R-448A remains the dominant A1 choice.
Service notes
POE oil required — same lubricant family as R-404A, so R-404A retrofit to R-448A typically does NOT require oil change [ahri700]. The lubricant compatibility is one of R-448A's primary retrofit advantages over A2L alternatives that may require different oil viscosity.
The 10°F temperature glide affects service measurement — use dew temperature for superheat (suction line) and bubble temperature for subcooling (liquid line). Single-curve approximation introduces measurement error equal to the glide. R-448A operating pressures are slightly lower than R-404A across the range; A1 classification means no A2L procedures required.
Phase-down timeline
No phase-down milestones documented for R-448A in this build. This may mean: (a) no regulatory phase-down currently published; (b) the refrigerant has local regulatory schedules not yet transcribed into the site dataset; or (c) it is a specialty refrigerant outside the main regulatory frameworks. For authoritative current status, consult the EPA AIM Act allocations (40 CFR Part 84), EU F-Gas Regulation 517/2014 + 2024/573, and the relevant national implementations of the Kigali Amendment.
Global warming potential, in context
Commercial refrigeration — medium temperature
Retrofit and replacement paths
R-448A replaces
Replacements for R-448A
Reading the R-448A PT chart — dew vs bubble matters
R-448A is a zeotropic blend with approximately 10°F glide. The PT chart shows two curves: bubble (saturated liquid) and dew (saturated vapor). Service measurement requires selecting the correct curve based on which line of the system you're measuring.
For suction-line superheat measurement, use the dew curve. The dew temperature at the measured suction pressure is the saturation reference; superheat = suction line temp − dew temperature. Using the bubble curve would understate superheat by ~10°F.
For liquid-line subcooling measurement, use the bubble curve. The bubble temperature at the measured discharge pressure is the saturation reference. Using the dew curve would overstate subcooling by the glide.
R-448A's glide is intermediate — larger than R-454B's 2°F but smaller than R-454C's 14°F or R-455A's 22°F. Most modern PT calculators and digital manifold gauges handle the curve selection automatically when R-448A is selected. Service technicians transitioning from R-404A (near-azeotropic, ~1°F glide) to R-448A (zeotropic, ~10°F glide) need to adopt the dew/bubble curve discipline that wasn't necessary for R-404A.
The 5-component blend hits multiple engineering targets simultaneously
R-448A's five-component composition was designed to optimize four constraints at the same time: maintain A1 safety class, reduce GWP substantially, match R-404A pressure envelope for retrofit, and preserve POE oil compatibility.
The component roles:
- R-32 (26%, GWP 675, A2L individually) — primary capacity contributor; pressure-envelope match with R-404A
- R-125 (26%, GWP 3500, A1 individually) — flammability suppressor that keeps the blend A1 despite the A2L components
- R-134a (21%, GWP 1430, A1 individually) — pressure tuning and capacity contribution
- R-1234yf (20%, GWP 4, A2L individually) — primary GWP-diluting HFO
- R-1234ze(E) (7%, GWP 7, A2L individually) — additional GWP dilution with slightly different vapor pressure profile
The mass-weighted GWP: 0.26 × 675 + 0.26 × 3500 + 0.21 × 1430 + 0.20 × 4 + 0.07 × 7 = 176 + 910 + 300 + 1 + 0.5 = approximately 1387 [ipccar5]. The R-125 component is the GWP-heavy element but is necessary for A1 flammability suppression.
Pressure envelope close to R-404A — retrofit-compatible
R-448A's pressure envelope is designed to closely match R-404A across the commercial refrigeration operating range, enabling retrofit of existing R-404A equipment without compressor or expansion-valve replacement. At 70°F R-448A bubble is 138 PSIG vs R-404A's 148 PSIG (CoolProp 7.2.0) — approximately 7% lower.
At low-temperature commercial refrigeration operating conditions (−20°F evaporator, 95°F condenser), R-448A pressures track R-404A within 5-10% across the cycle. The compressor sees similar pressure ratios; the expansion valve sees similar liquid pressure; the system can typically be retrofitted by refrigerant change alone without component replacement.
The 10°F glide is the operational adjustment from R-404A practice. R-404A is near-azeotropic (~1°F glide); R-448A's glide requires dew/bubble curve discipline for accurate superheat and subcooling measurement. Equipment-OEM retrofit documentation typically includes pressure-temperature lookup tables specific to R-448A.
GWP 1387 — substantial reduction but not the long-term answer
R-448A's GWP of 1387 represents a ~65% reduction from R-404A's 3922 — substantial environmental improvement [ipccar5]. The reduction comes from the R-1234yf (20%) and R-1234ze(E) (7%) components, which collectively dilute the blend's GWP without affecting the A1 safety classification.
The 1387 figure is not low enough to clear the EU F-Gas 150-GWP threshold for the strictest commercial refrigeration categories. EU F-Gas Regulation revisions through 2024 may tighten thresholds in some segments where R-448A no longer complies. For long-term GWP compliance, A2L alternatives (R-454C, R-455A at 148) or R-744 transcritical (GWP 1) are required.
R-448A is therefore a transitional refrigerant — better than R-404A by 65% but not the structural low-GWP destination. Its market role is retrofit of existing R-404A equipment that has remaining service life but cannot economically be replaced with A2L equipment requiring full redesign. Through the 2020s, R-448A retrofit fills the gap between R-404A end-of-life and full replacement with A2L or natural-refrigerant equipment.
R-448A at commercial refrigeration service temperatures
R-448A saturation values across typical commercial refrigeration operating conditions (bubble / dew where glide is meaningful):
- −40°F (deep freezer) — bubble approximately 6 inHg vac / dew approximately 11 inHg vac.
- −20°F (frozen food) — bubble approximately 18 PSIG / dew approximately 13 PSIG.
- 0°F (freezer) — bubble approximately 41 PSIG / dew approximately 35 PSIG.
- 30°F (refrigerated case) — bubble approximately 75 PSIG / dew approximately 65 PSIG.
- 70°F (bench reference) — bubble 138 PSIG / dew 125 PSIG.
- 95°F (summer condensing) — bubble approximately 220 PSIG / dew approximately 200 PSIG.
For service measurement: dew curve for superheat, bubble curve for subcooling. Standard 500-800 PSI manifold gauges handle the envelope; A1 classification means no A2L equipment additions required.
Service procedures — standard A1 with glide handling added
R-448A service uses standard A1 HFC procedures with two adjustments from R-404A practice: dew/bubble curve discipline for the 10°F glide, and slightly lower operating pressures across the cycle.
| Equipment / procedure | R-404A | R-448A | | --- | --- | --- | | Manifold gauge rating | 500-800 PSI | 500-800 PSI | | Recovery cylinder | Standard 600 PSI | Standard 600 PSI | | Lubricant | POE | POE (same family — no oil change needed) | | Curve selection for superheat | Single curve (near-azeotropic) | Dew curve at suction pressure | | Curve selection for subcooling | Single curve (near-azeotropic) | Bubble curve at discharge pressure | | Charge by weight | Required | Required (zeotropic — no top-off) | | Compressor motor | Standard hermetic | Standard hermetic (A1) | | Safety class procedures | Standard A1 | Standard A1 | | Vacuum target | 500 microns held 30+ min | 500 microns held 30+ min |
The lubricant family preservation (POE to POE) is the major retrofit advantage. R-404A equipment uses POE; R-448A uses POE; no oil change required. This is operationally simpler than alternatives requiring oil chemistry change.
R-448A vs R-449A — competing A1 R-404A retrofits
R-448A and R-449A are competing A1 HFC/HFO blends marketed as R-404A retrofit refrigerants. Both have GWP ~1390 (R-448A: 1387, R-449A: 1397), both preserve A1 safety, both use POE oil, both have ~10°F glide. The choice between them is typically driven by manufacturer relationship rather than technical performance differentiation.
| Property | R-448A | R-449A | | --- | --- | --- | | Manufacturer | Honeywell (Solstice N40) | Chemours (Opteon XP40) | | Composition | 5 components: R-32/R-125/R-134a/R-1234yf/R-1234ze 26/26/21/20/7 | 4 components: R-32/R-125/R-134a/R-1234yf 24.3/24.7/25.7/25.3 | | GWP | 1387 | 1397 | | Glide @ 70°F | ≈10°F | ≈10°F | | Safety class | A1 | A1 | | Lubricant | POE | POE | | Retrofit procedure | Identical to R-404A | Identical to R-404A |
Performance differences between R-448A and R-449A are small enough that field service can treat them as effectively equivalent for most applications. Equipment-OEM specifications and refrigerant-distributor relationships typically determine which one any given installation uses.
How to think about R-448A in 2026 and beyond
R-448A occupies the R-404A retrofit niche through the late 2020s. For existing R-404A commercial refrigeration equipment with substantial remaining service life that cannot economically be replaced with new A2L or R-744 equipment, R-448A provides ~65% GWP reduction while preserving A1 safety classification and POE lubricant compatibility.
The retrofit economics are favorable. The procedure is operationally simple (recover R-404A, replace filter-drier, evacuate, recharge by weight) and requires no equipment-level redesign or lubricant change. R-448A capacity matches R-404A within 5% in most commercial refrigeration applications; system efficiency is comparable.
The long-term trajectory is replacement, not continued R-448A retrofit. As EU F-Gas Regulation revisions through 2024 may tighten thresholds in commercial refrigeration categories where R-448A no longer complies, the new-equipment market shifts to A2L (R-454C, R-455A at 148 GWP) or R-744 transcritical (GWP 1). R-448A bridges the gap between R-404A end-of-life and full replacement with low-GWP architecture.
For service technicians, R-448A work is identical to R-404A work plus dew/bubble curve discipline for the 10°F glide. Equipment OEM training programs cover the glide handling; modern PT calculators handle curve selection automatically.
Frequently asked
›What is the normal operating pressure of R-448A?
Slightly lower than R-404A across the operating range. At 70°F R-448A saturation is approximately 138 PSIG bubble / 125 PSIG dew (CoolProp 7.2.0). Compare to R-404A at 70°F (148 PSIG, near-azeotropic).
For low-temperature commercial refrigeration at −20°F evaporator, R-448A saturation is approximately 13 PSIG dew. For medium-temp at 30°F evaporator, approximately 53 PSIG dew. The slightly lower pressures and the ~10°F glide are the key operational differences from R-404A.
›Why does R-448A have five components?
To hit multiple targets simultaneously: A1 safety (R-125 component suppresses flammability), pressure-envelope match with R-404A (R-32 and R-134a tune pressure), substantial GWP reduction (R-1234yf and R-1234ze dilute GWP), and POE oil compatibility. No simpler binary or ternary blend optimizes all four constraints at the same time.
The 26/26/21/20/7 composition was engineered by Honeywell after extensive testing of alternative compositions. The five-component complexity is a feature, not a bug — it represents thoughtful trade-off engineering for the retrofit application.
›What's the difference between R-448A and R-449A?
Both are A1 HFC/HFO blends marketed as R-404A retrofit refrigerants with GWP ~1390. R-448A (Honeywell Solstice N40) is quinary (5 components): R-32/R-125/R-134a/R-1234yf/R-1234ze 26/26/21/20/7. R-449A (Chemours Opteon XP40) is quaternary (4 components): R-32/R-125/R-134a/R-1234yf 24.3/24.7/25.7/25.3.
Performance is essentially equivalent. The choice between them is typically driven by manufacturer relationships and equipment OEM specification. Honeywell-aligned operators use R-448A; Chemours-aligned operators use R-449A.
›Can I retrofit R-404A to R-448A without changing oil?
Yes — both refrigerants use POE oil. The R-404A POE oil is compatible with R-448A operation; no oil change is required. The standard retrofit procedure: recover R-404A, replace filter-drier, evacuate to 500 microns, recharge with R-448A by weight to the OEM nameplate amount.
Verify oil condition before retrofit. If the POE oil shows degradation (moisture, acidity, color change), replace it as part of the retrofit. But oil family compatibility is preserved across R-404A → R-448A transition, unlike R-22 → R-404A retrofit which requires mineral oil to POE oil change.
›What does R-448A's GWP of 1387 mean?
A 1 kg release of R-448A traps approximately 1,387 times more heat over 100 years than 1 kg of CO₂ (IPCC AR5, mass-weighted from the five components) [ipccar5]. The 1387 figure represents a ~65% reduction from R-404A's 3922 — substantial improvement while preserving A1 safety classification.
The reduction is not enough to clear the EU F-Gas 150-GWP threshold for the strictest commercial refrigeration categories. R-448A is a transitional refrigerant — better than R-404A but not the long-term low-GWP destination. For very-low GWP, A2L alternatives (R-454C, R-455A at 148) or R-744 (CO₂, GWP 1) are required.
›How do I measure superheat on R-448A?
Use the dew temperature at suction pressure. R-448A's 10°F glide means using the bubble curve would understate superheat by approximately 10°F — large enough to cause meaningful charging errors. The dew curve corresponds to the suction-line state where refrigerant has fully evaporated.
Modern PT calculators handle the dew/bubble selection automatically when R-448A is selected.
›What lubricant does R-448A use?
Polyolester (POE) oil — same lubricant family as R-404A, R-410A, and R-32 [ahri700]. Typical viscosity is ISO 32 for medium-temperature commercial refrigeration, ISO 22 or 46 for low-temperature applications. Verify against equipment OEM specification.
The POE oil compatibility is a primary retrofit advantage of R-448A over A2L alternatives — R-404A equipment already uses POE, so no oil change is required when retrofitting to R-448A.
›Is R-448A safe to handle?
ASHRAE class A1 — non-toxic and non-flammable [ashrae34]. Standard HFC service procedures apply. No A2L-specific requirements: no sealed motor compulsion, no charge limits per A2L standards, no nitrogen-purge mandate for brazing beyond standard HFC practice.
The A1 classification preservation is one of R-448A's primary retrofit advantages — R-404A equipment is A1-rated and can accept R-448A without safety-class compliance changes. A2L alternatives would require equipment-level redesign.
Sources & citations
- [1]ASHRAE Standard 34-2022 — Designation and Safety Classification of Refrigerants
- [2]IPCC AR5 (2014) Working Group I, Chapter 8, Table 8.A.1
- [3]EPA AIM Act — 40 CFR Part 84 Subpart BFinal Rule Oct 2021https://www.epa.gov/climate-hfcs-reduction
- [4]EU F-Gas Regulation 517/2014 (revised 2024)
- [5]EPA SNAP — R-448A acceptable for commercial refrigeration retrofit and new equipment
- [6]CoolProp 7.2.0 (Bell, Wronski, Quoilin, Lemort 2014)
- [7]AHRI Standard 700-2019 — Specifications for Refrigerants
- [8]Honeywell Solstice N40 (R-448A) Technical Information