R404A / R507A / R448A / R449A: Composition, GWP and Retrofit Limits

Sun, 20 Sep 2026 · HARMONY TECHNOLOGY (ZHEJIANG) CO., LTD.

R404A / R507A / R448A / R449A: Composition, GWP and Retrofit Limits

These four are not interchangeable. Composition determines glide, and glide determines whether a retrofit is a drop-in or a rebuild.

1. Composition first — everything else follows

数据出处（本节数值逐项核过，不取记忆值）：R448A 组分与 GWP 1386(AR4) 见 Arkema Forane® 448A TDS（CAS 75-10-5 / 354-33-6 / 754-12-1 / 811-97-2 / 29118-24-9）与 agas 产品页； R449A 组分 24.3/24.7/25.7/25.3 与 GWP 1397(AR4) 见 Arkema Lower-GWP Guide 与公开文献（PMC5528183）。 ⇒ 提醒：同一制冷剂的 GWP 会因评估报告不同而不同（如 R404A：AR4 约 3922，而文献引用 IPCC 2013 口径为 3300）——所以引用 GWP 必须同时给出报告口径，否则两个正确数字也能比出错误结论。

Two immediate consequences:

1. R404A and R507A are both ~3900 GWP — swapping one for the other changes nothing about regulatory exposure. They are both high-GWP HFC blends.
2. R448A and R449A are ~1390 GWP and zeotropic — a 60%+ GWP reduction that comes with temperature glide, which is the operating difference that matters.

2. Azeotropic vs zeotropic — the practical difference

⇒ This is why “retrofit” is a system question, not a gas question. A zeotropic blend that leaks and is topped up in vapour phase no longer matches its nameplate composition.

3. What a retrofit actually requires (beyond changing the gas)

⇒ “Drop-in” is a marketing word, not a technical claim. The technical claim is “compatible after the following six checks” — if a supplier cannot name them, the gas is not the question. The mechanism by which an asserted drop-in fails on operating pressure, lubricant miscibility, molecular polarity and flammability class is set out in R22, R32, R410A and R407C: physical properties compared.

4. Regulatory driver (why this matters commercially)

Under the EU F-gas Regulation (EU) 2024/573, GWP thresholds determine which equipment may be placed on the market and which refrigerants may be used for service. A blend with GWP ~3900 and a blend with GWP ~1390 sit on different sides of those thresholds.

⇒ Consequence for procurement: specifying by “the refrigerant that works in our system” is insufficient if the system is placed on an EU market — the GWP of the charge is itself regulated.

5. How to compare offers correctly

Ask for, in writing:

1. Composition (component list with mass %), not just the number.
2. GWP and which assessment report it is quoted against (AR4 vs AR5 vs AR6 give different values for the same refrigerant — a number without the report is not comparable).
3. Glide at the intended evaporating/condensing temperatures.
4. The retrofit checklist for the specific system.
5. CAS numbers of each component, for customs and safety documentation.

⇒ Point 2 is the most common trap: AR4 and AR5 GWP values for these blends differ, and comparing an AR4 figure against an AR5 figure produces a false conclusion.

6. Summary table — what to use where

What we can provide

For any of these blends we can supply the component list with mass percentages, CAS numbers for each component, the GWP with its assessment-report basis, and relevant safety classification — so your engineering team can evaluate a retrofit against its own system rather than against a marketing claim.

Contact us with: the existing refrigerant, the system type, and the destination market.

Prepared by Harmony Technology (Zhejiang) Co., Ltd. — a trading company. Technical data above is referenced to public standards; system-specific retrofit decisions remain the responsibility of the qualifying engineer.