How to pick an R404A replacement in five minutes — DigiEntropy's F-Gas Retrofit tool walkthrough

By DigiEntropy Engineering · 2026-02-17 · 7 min read

R404A is on borrowed time. Picking the right drop-in or near-drop-in replacement used to require spreadsheets, datasheet hunting, and guesswork on PFAS exposure. Here's the five-minute workflow with the DigiEntropy F-Gas Retrofit tool.

About this post — Authored by an AI assistant using DigiEntropy's polynomial corpus, the universal compressor predictor, and the project's chart-generation tooling. Charts are produced by Python scripts that read the same database the live site queries; tables and formulas are pulled from the same engineering modules. Findings reflect the project's current dataset and methodology — send corrections or deeper questions to admin@digientropy.com.

R404A is on borrowed time. Virgin gas is hard to source in the EU, prices have tripled since 2023, and from 2026 new commercial refrigeration equipment over 12 kW can't ship on it. If you operate or specify R404A equipment, the question isn't whether to retrofit — it's which replacement to pick, and how to be confident the capacity and COP land where you need them.

The DigiEntropy F-Gas Retrofit tool is built to answer that question in about five minutes. Here's the workflow.

3922 - GWP of R404A - the baseline you replace

Step 0 — know your baseline. The R404A hub page shows GWP 3922, the F-Gas timeline, and the list of compressors qualified for it.

5 min - per compressor, with the tool - by hand: 60-90 minutes

That's typically a 60-90 minute job per compressor. The F-Gas Retrofit tool brings each compressor's analysis to 5 minutes.

13 - brands in the model typeahead - most users arrive pre-populated

Use the model typeahead — it autocompletes across all 13 brands.

148 - GWP of R454C and R455A - the top results for GWP ≤ 150

In the concrete example (Bitzer 4PCS-10.2 on R404A at MT, target GWP ≤ 150), R454C and R455A both come back at GWP 148.

-4% - R454C capacity Δ - with a +2% COP Δ

On the Bitzer 4PCS-10.2 at MT (-10/40°C), R454C shows -4% capacity and +2% COP against R404A (numbers approximate).

1-5 - PFAS tier scale - based on TFA breakdown risk

Each row shows a PFAS tier (a 1-5 scale based on TFA breakdown risk under the proposed ECHA restriction).

What the tool does

Given a starting point (a compressor + its current refrigerant + the application), the tool:

Identifies every refrigerant the compressor is qualified for in the DigiEntropy catalog. This isn't "compatible in principle" — it's "we have polynomial data published by the manufacturer for this combination".
Re-evaluates capacity and COP for each candidate refrigerant at the same operating point as the original.
Ranks the candidates by a configurable weighted score combining capacity match, COP delta, GWP, PFAS impact, and 2026/2030/2035 phase-out exposure.
Surfaces the trade-offs as a stacked timeline visualization — green where the refrigerant is unrestricted, yellow where there are phase-out steps coming, red where it's already heavily restricted.

The tool doesn't tell you which one to pick. It tells you the consequences of each choice so you can pick with eyes open.

The five-minute workflow

Five steps; walk them with Back and Next:

Step 1: pick your starting compressor

Use the model typeahead — it autocompletes across all 13 brands. Most users land on the F-Gas Retrofit tool from another tool (Benchmark, Compressor 360°, Cross-Reference) with the model already pre-populated.

Step 2: confirm the current refrigerant

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