F-Gas CO₂-Equivalent Calculator

It calculates the tonnes CO₂-equivalent of a refrigerant charge using the AR4 global warming potential values that the UK F-Gas Regulation uses, then tells you which statutory leak check frequency band the system falls into (≥5 t, ≥50 t, ≥500 t), what recordkeeping is required, and how the frequency changes if a permanent automatic leak detection system is fitted. Covers 10 common HFC, HCFC and HFO refrigerants used in UK commercial buildings.

Tonnes CO₂-equivalent = refrigerant charge in kg × GWP ÷ 1000. For example, 8 kg of R410A (GWP 2088) = (8 × 2088) ÷ 1000 = 16.7 tonnes CO₂e, which falls in the 5–50 t band and requires annual leak checks. The threshold is what drives the schedule, not the raw refrigerant mass — a small charge of a very high-GWP refrigerant can trigger the same compliance band as a large charge of a low-GWP one.

AR4 values, which are the reference set used by the UK F-Gas Regulation (Fluorinated Greenhouse Gases Regulations 2015 as amended, implementing Regulation (EU) No 517/2014). AR5 and AR6 values exist and are used in some climate accounting contexts, but for UK F-Gas compliance the AR4 values are the governing reference. R410A = 2088, R32 = 675, R134a = 1430, R407C = 1774, R22 = 1810, R454B = 466.

Below 5 t CO₂e: no statutory leak check requirement. 5 to 50 t: annual leak check (24-monthly with permanent leak detection). 50 to 500 t: 6-monthly (annual with leak detection). 500 t and above: quarterly (6-monthly with leak detection). All leak checks must be carried out by an F-Gas certified engineer, and the system must keep a full logbook of refrigerant type and charge, leak checks, top-ups and certified engineer details.

Yes — the F-Gas Regulation permits the leak check interval to double (i.e. the frequency to halve) when a permanent automatic leak detection system is fitted, monitored, and audited. A permanent leak detection system is only mandatory from 500 t CO₂e (Article 5(1)); below that it is optional, and fitting one is what halves the frequency. The tool's checkbox applies this halving automatically.

R22 (HCFC) has been banned for new equipment since 2010 and may only be serviced from reclaimed/recycled stock since 2015. High-GWP HFCs including R410A, R134a and R404A are subject to the F-Gas phase-down quota mechanism, with placing-on-the-market restrictions for new equipment from 2025/2027 depending on the application. R32, R454B, R513A and R1234yf are current lower-GWP options. The tool flags the regulatory status of each refrigerant in the result.

No. The tool is for compliance planning — it doesn't replace the certified engineer who must actually perform the leak check, top-up, decommission or recovery. All refrigerant handling in the UK and EU must be carried out by an F-Gas certified engineer under the F-Gas Regulation. Use the tool to plan and document; use the engineer to execute.

For systems above 5 t CO₂e: refrigerant type and charge weight, dates and findings of every leak check, any leaks found and how they were repaired, refrigerant added or recovered, certified engineer details, and dates of any decommissioning. These records must be kept for at least five years. For systems at 500 t CO₂e and above, where a leak detection system is mandatory, that system must itself be checked at least every 12 months and those checks recorded.

The chiller diagnostic tool helps engineers measure superheat and subcool on the same refrigerants this calculator covers — and many chiller fault conditions (HP/LP trips, abnormal superheat) flag the same charge issues that drive F-Gas compliance work. Use the chiller diagnostic to spot a refrigerant charge problem during a site visit, then use the F-Gas calculator to confirm the compliance band the system falls into.

R290 (propane) and R600a (isobutane) are hydrocarbon refrigerants with extremely low GWP (3 and 3 respectively). They are not classified as fluorinated greenhouse gases and therefore sit outside the F-Gas Regulation's leak check regime — although other safety regulations apply because they are flammable (A3 classification). They are not currently included in this calculator's selector but their GWP values are tiny, so even very large charges would not trigger any F-Gas leak check threshold.

Yes, completely free with no signup required. The calculator runs entirely in your browser — refrigerant data, charge weights and results are never sent to a server. The reference data (GWP values, compliance band thresholds, recordkeeping requirements) is static curated content. Nothing tracked, nothing stored.

This tool gives manufacturer-agnostic compliance guidance. PM Assist lets you upload the specific chiller's O&M manual, F-Gas logbook history, and commissioning data, then search them in plain English with source-cited answers. The two work together: the calculator tells you the regulatory framework and what band applies; PM Assist retrieves the exact charge weight and refrigerant type from the asset's documentation.