| Emissions Source | Unit | kg CO₂–e/unit |
|---|---|---|
| Refrigerants | ||
| Isobutane (R–600a) – C₄H₁₀ | kg | 3 |
| Methane – CH₄ | kg | 28 |
| Nitrous oxide (R–744a) – N₂O | kg | 265 |
| Carbon dioxide (R–744) – CO₂ | kg | 1 |
| Propane (R–290) – C₃H₈ | kg | 0.06 |
| Substances controlled by the Montreal Protocol | ||
| CFC–115 (R–115) – CClF₂CF₃ | kg | 7670 |
| Halon–1211 (R–1211) – CBrClF₂ | kg | 1750 |
| Halon–1301 (R–1301) – CBrF₃ | kg | 6290 |
| HCFC–22 (R–22) – CHClF₂ | kg | 1760 |
| HCFC–123 (R–123) – CHCl₂CF₃ | kg | 79 |
| HCFC–124 (R–124) – CHClFCF₃ | kg | 527 |
| Halon–2402 (R–2402) – CBrF₂CBrF₂ | kg | 1470 |
| Carbon tetrachloride (R–10) – CCl₄ | kg | 1730 |
| Methyl bromide – CH₃Br | kg | 2 |
| CFC–113 (R–113) – CCl₂FCClF₂ | kg | 5820 |
| Methyl chloroform – CH₃CCl₃ | kg | 160 |
| CFC–13 (R–13) – CClF₃ | kg | 13900 |
| CFC–11 (R–11) – CCl₃F | kg | 4660 |
| CFC–12 (R–12) – CCl₂F₂ | kg | 10200 |
| HCFC–141b (R–141b) – CH₃CCl₂F | kg | 782 |
| HCFC–142b (R–142b) – CH₃CClF₂ | kg | 1980 |
| HCFC–225ca (R–225ca) – CHCl₂CF₂CF₃ | kg | 127 |
| HCFC–225cb (R–225cb) – CHClFCF₂CClF₂ | kg | 525 |
| CFC–114 (R–114) – CClF₂CClF₂ | kg | 8590 |
| HCFC–21 – CHCl₂F | kg | 148 |
| Hydroflurocarbons | ||
| HFC–245ca – CH₂FCF₂CHF₂ | kg | 716 |
| HFC–236cb – CH₂FCF₂CF₃ | kg | 1210 |
| HFC–236fa (R–236fa) – CF₃CH₂CF₃ | kg | 8060 |
| HFC–161 – CH₃CH₂F | kg | 4 |
| HFC–152a (R–152a) – CH₃CHF₂ | kg | 138 |
| HFC–152 – CH₂FCH₂F | kg | 16 |
| HFC–236ea – CHF₂CHFCF₃ | kg | 1330 |
| HFC–32 (R–32) – CH₂F₂ | kg | 677 |
| HFC–41 – CH₃F | kg | 116 |
| HFC–23 (R–23) – CHF₃ | kg | 12400 |
| HFC–134a (R–134a) – CH₂FCF₃ | kg | 1300 |
| HFC–125 (R–125) – CHF₂CF₃ | kg | 3170 |
| HFC–43–10mee – CF₃CHFCHFCF₂CF₃ | kg | 1650 |
| HFC–245fa (R–245fa) – CHF₂CH₂CF₃ | kg | 858 |
| HFC–227ea (R–227ea) – CF₃CHFCF₃ | kg | 3350 |
| HFC–143a (R–143a) – CH₃CF₃ | kg | 4800 |
| HFC–143 – CH₂FCHF₂ | kg | 328 |
| HFC–134 – CHF₂CHF₂ | kg | 1120 |
| HFC–365mfc (R–365mfc) – CH₃CF₂CH₂CF₃ | kg | 804 |
| Perfluorinated Compounds | ||
| PFC–91–18 – C₁₀F₁₈ | kg | 7190 |
| PFC–51–14 – n–C₆F₁₄ | kg | 7910 |
| Trifluoromethyl sulphur pentafluoride – SF₅CF₃ | kg | 17400 |
| Perfluorocyclopropane – c–C₃F₆ | kg | 9200 |
| PFC–318 – c–C₄F₈ | kg | 9540 |
| PFC–41–12 – n–C₅F₁₂ | kg | 8550 |
| PFC–31–10 – C₄F₁₀ | kg | 9200 |
| Sulphur hexafluoride – SF₆ | kg | 23500 |
| PFC–218 – C₃F₈ | kg | 8900 |
| Nitrogen trifluoride – NF₃ | kg | 16100 |
| PFC–14 – CF₄ | kg | 6630 |
| PFC–116 – C₂F₆ | kg | 11100 |
| Fluorinated Ethers | ||
| HFE–347mcf2 – CHF₂CH₂OCF₂CF₃ | kg | 854 |
| HFE–347mcc3 – CH₃OCF₂CF₂CF₃ | kg | 530 |
| HFE–338mcf2 – CF₃CH₂OCF₂CF₃ | kg | 929 |
| HCFE–235da2 (Isoflurane) – CHF₂OCHClCF₃ | kg | 491 |
| HFE–227ea – CF₃CHFOCF₃ | kg | 6450 |
| HFE–125 – CHF₂OCF₃ | kg | 12400 |
| HFE–134 – CHF₂OCHF₂ | kg | 5560 |
| HFE–143a – CH₃OCF₃ | kg | 523 |
| HFE–347pcf2 – CHF₂CF₂OCH₂CF₃ | kg | 889 |
| HFE–356mec3 – CH₃OCF₂CHFCF₃ | kg | 387 |
| HFE–356pcc3 – CH₃OCF₂CF₂CHF₂ | kg | 413 |
| HFE–356pcf2 – CHF₂CH₂OCF₂CHF₂ | kg | 719 |
| HFE–356pcf3 – CHF₂OCH₂CF₂CHF₂ | kg | 446 |
| HFE–365mcf3 – CF₃CF₂CH₂OCH₃ | kg | 1 |
| HFE–374pc2 – CHF₂CF₂OCH₂CH₃ | kg | 627 |
| HFE–449sl (HFE–7100) – C₄F₉OCH₃ | kg | 421 |
| HFE–569sf2 (HFE–7200) – C₄F₉OC₂H₅ | kg | 57 |
| HFE–245fa2 – CHF₂OCH₂CF₃ | kg | 812 |
| HFE–254cb2 – CH₃OCF₂CHF₂ | kg | 301 |
| HFE–263fb2 – CF₃CH₂OCH₃ | kg | 1 |
| HFE–245fa1 – CHF₂CH₂OCF₃ | kg | 828 |
| HFE–236ea2 – CHF₂OCHFCF₃ | kg | 1790 |
| HFE–236fa – CF₃CH₂OCF₃ | kg | 979 |
| HFE–245cb2 – CH₃OCF₂CF₃ | kg | 654 |
| HFE–329mcc2 – CHF₂CF₂OCF₂CF₃ | kg | 3070 |
| HFE–43–10pccc124 (H–Galden 1040x) – CHF₂OCF₂OC₂F₄OCHF₂ | kg | 2820 |
| HFE–236ca12 (HG–10) – CHF₂OCF₂OCHF₂ | kg | 5350 |
| HFE–338pcc13 (HG–01) – CHF₂OCF₂CF₂OCHF₂ | kg | 2910 |
| Perfluoropolyethers | ||
| PFPMIE – CF₃OCF(CF₃)CF₂OCF₂OCF₃ | kg | 9710 |
| Hydrocarbons and other compounds – Direct Effects | ||
| Chloroform – CHCl₃ | kg | 16 |
| Methylene chloride – CH₂Cl₂ | kg | 9 |
| Halon–1201 – CHBrF₂ | kg | 376 |
| Methyl chloride – CH₃Cl | kg | 12 |
| Dimethylether – CH₃OCH₃ | kg | 1 |
| Refrigerant blends: Zeotropes | ||
| 416A – R–134a/124/600 (59.0/39.5/1.5) | kg | 975.21 |
| 422A – R–125/134a/600a (85.1/11.5/3.4) | kg | 2847.27 |
| 409A – R–22/124/142b (60.0/25.0/15.0) | kg | 1484.75 |
| 436A – R–290/600 (56.0/44.0) | kg | 1.3536 |
| 406A – R–22/600a/142b (55.0/4.0/41.0) | kg | 1779.92 |
| 403B – R–290/22/218 (5.0/56.0/39.0) | kg | 4456.6 |
| 410A – R–32/125 (50.0/50.0) | kg | 1923.5 |
| 407C – R–32/125/134a (23.0/25.0/52.0) | kg | 1624.21 |
| 407F – R–32/125/134a (30.0/30.0/40.0) | kg | 1674.1 |
| 408A – R–125/143a/22 (7.0/46.0/47.0) | kg | 3257.1 |
| 502 – R–22/115 (48.8/51.2) | kg | 4785.92 |
| 436B – R–290/600 (52.0/48.0) | kg | 1.4712 |
| 404A – R–125/143a/134a (44.0/52.0/4.0) | kg | 3942.8 |
| 417A – R–125/134a/600 (46.6/50.0/3.4) | kg | 2127.32 |
| 413A – R–218/134a/600a (9.0/88.0/3.0) | kg | 1945.09 |
| 409B – R–22/124/142b (65.0/25.0/10.0) | kg | 1473.75 |
| Refrigerant blends: Azeotropes | ||
| 507A – R–125/143a (50.0/50.0) | kg | 3985 |
| Medical Gases (AR5 GWPs) | ||
| Entonox – N2O/O2 (57.9/42.1) | kg | 153.435 |
| HCFE–235da2 (Isoflurane) – CHF₂OCHClCF₃ | kg | 491 |
| HFE–347mmz1 (Sevoflurane) – (CF₃)₂CHOCH₂F | kg | 216 |
| HFE–236ea2 (Desflurane) – CHF₂OCHFCF₃ | kg | 1790 |
| HFE–347mmz1 (Sevoflurane) – (CF₃)₂CHOCH₂F | kg | 216 |
| HCFE–235da2 (Isoflurane) – CHF₂OCHClCF₃ | kg | 491 |
| HFE–236ea2 (Desflurane) – CHF₂OCHFCF₃ | kg | 1790 |
| Entonox – N2O/O2 (57.9/42.1) | kg | 153.435 |
4 Refrigerant and other gases
4.1 Overview of emission factor changes from 2025 to 2026
| Section | Total EFs | EFs added | EFs removed | EFs changed | Explanation for change |
|---|---|---|---|---|---|
| Medical Gases Use; Refrigerant Use | 4 | 0 | 0 | 4 | CO2 values are now populated by duplicating CO2e values (previously null); values are identical because emissions are calculated directly as CO2 equivalent using GWP. |
| Refrigerant Use | 107 | 0 | 0 | 107 | CO2 values are now populated by duplicating CO2e values (previously null); values are identical because emissions are calculated directly as CO2 equivalent using GWP. |
For detailed information on the emission factor changes, download the Emission factor changes CSV file from Appendix G.
4.2 Refrigerant use
GHG emissions from hydrofluorocarbons (HFCs) are associated with unintentional leaks and spills from refrigeration units, HVAC systems, air conditioners and heat pumps. Quantities of HFCs in a GHG inventory may be small, but HFCs have very high GWPs so emissions from this source may be material. Also, emissions associated with this sector have grown significantly as they replace ozone depleting chemicals such as chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs).
The list of refrigerant gases is continuously evolving with technology and scientific knowledge. We note that if a known gas is not listed in this guide, it does not imply there is no impact.
Emissions from HFCs are determined by estimating refrigerant equipment leakage and multiplying the leaked amount by the GWP of that refrigerant. There are three methods depending on the data available, see section Section 4.3.1, Section 4.3.2, and Section 4.3.3.
If you consider it likely that emissions from refrigerant equipment and leakage are a significant proportion of your total emissions (eg, greater than 5 per cent), include them in your GHG inventory. You may need to carry out a preliminary screening test to determine if this is a material source.
If the reporting entity owns or controls the refrigeration units, emissions from refrigeration are direct (Scope 1). If the entity leases the unit, associated emissions should be reported under indirect (Scope 3) emissions.
4.3 Global warming potentials (GWPs) of refrigerants and other GHGs
Table 4.2 details the GWPs (shown in kg CO2-e) of the refrigerants included in this section. The GWP is effectively the emission factor for each unit of refrigerant gas lost to the atmosphere. The guide uses the 100 year GWPs from the IPCC’s AR5 to ensure consistency with New Zealand’s Greenhouse Gas Inventory 1990–2024.
Some refrigerants are a mixture (or blend) of gases. If you know the blend composition, you can calculate the GWP based on the percentage mass of each gas. Alternatively, for the AR5 GWP of various refrigerant mixtures, see Section B.1.
These emission factors refer to direct emissions, not the indirect emissions associated with the production and supply of these refrigerants.
4.3.1 GHG inventory development
There are three approaches to estimate HFC leakage from refrigeration equipment, depending on the data available. The ideal method is the top-up method, Method A. Method B is the next best option. Method C is the least preferred because it has the most assumptions.
It is stressed that for all methods, users must individually identify the type of refrigerant because the GWPs vary widely.
Entities should indicate the method(s) used in their inventories to reflect the levels of accuracy and uncertainty.
4.3.2 Method A: Top-up
The best method to determine if emissions have occurred is through confirming if any top-ups were necessary during the measurement period. A piece of equipment is ‘charged’ with refrigerant gas, and any leaked gas must be replaced. Assuming that the system was at capacity before the leakage occurred and is full again after a top-up, the amount of top-up gas is equal to the gas leaked or lost to the atmosphere. The equipment maintenance service provider can typically provide information about the actual amount of refrigerant used to replace what has leaked.
\[ \begin{aligned} \text{Gas used (kg)} \times \text{GWP} &= \text{Emissions (kg CO}_{2}\text{-e)} \end{aligned} \]
Where:
- E = emissions from equipment in kg CO2-e
- GWP = the 100-year global warming potential of the refrigerant used in equipment Table 4.2, shown as kg CO2-e
4.3.3 Methods B and C: Screening
If top-up amounts are not available, we recommend using one of the following two methods for estimating leakage, depending on the equipment and available information. Section B.1 details both methods.
Method B is based on default leakage rates and known refrigerant type and volume. Use Method B when the type and amount of refrigerant held in a piece of equipment are known.
Method C is the same as Method B except that it allows default refrigerant quantities to be used as well as default leakage rates. Use Method C to estimate both volume of refrigerant and leakage rate when the amount of refrigerant held in a piece of equipment is not known.
Methods B and C are based on the screening approach outlined in the GHG Protocol HFC tool (WRI/WBCSD, 2005).
For most equipment, Method B is acceptable, especially for factory and office situations where refrigeration and air-conditioning equipment is incidental rather than central to operations. In some cases, Method C is only suitable for a screening estimate. Screening is a way of determining if the equipment should be included or excluded based on materiality of emissions from refrigerants. Entities should then try to source data based on the top-up-method.
We provide refrigerant emissions calculation examples below.
Company A performs a stocktake of refrigeration-related equipment and identifies the following units:
- one large commercial-sized chiller unit
- one commercial-sized office air conditioning unit.
Using the top-up approach, the calculation is as follows:
4.3.3.1 REFRIGERANT USE METHOD A: EXAMPLE CALCULATION
Method A: Top-up
Chiller unit: During the 2022 calendar year, a service technician confirmed a top-up of 6 kg of HFC-134a (AR5 GWP = 1,300) in December 2022. The technician also confirmed that when last serviced at the end of December 2021, no top-ups were needed. So, we assume all the 6 kg of gas was lost during calendar year 2022.
So, for the 2022 calendar,
6 kg HFC-134a x 1300 = 7,800 kg CO₂-e
Air conditioning unit: During the 2022 calendar year, a service technician confirmed a top-up of 6 kg of HFC-143a (AR5 = 4,800) in July 2022. The technician also confirmed that when last serviced at the end of July 2021, no top-ups were needed. So, we assume all the gas was lost at an even rate during the 12 months between service visits, and six of those months sit in the 2022 measurement period.
6 kg/12 months = 0.5 kg per month
So, for the 2022 calendar year inventory, 0.5 × 6 months = 3 kg. Emissions calculate as:
3 kg HFC-143a x 4800 = 14,400 kg CO₂-e
Note: Numbers may not add due to rounding.
If information was not available from the technician, Company A could use the following approach:
4.3.3.2 REFRIGERANT USE METHOD B: EXAMPLE CALCULATION
Method B: Screening method with default annual leakage rate
Chiller unit: Compliance plates on the equipment confirm the refrigerant is HFC-134a (AR5 GWP = 1,300) and the volume held is 12 kg. For the chiller unit size, the default leakage rate is 8%.
So, for the 2022 calendar year,
12 kg HFC-134a x 1300 * 8% = 1,250 kg CO₂-e
Air conditioning unit: A service technician confirms the refrigerant is HFC-143a (AR5 GWP = 4,800) and the volume held is 12 kg. For the size of the unit, the default leakage rate is 3%.
So, for the 2022 calendar year,
12 kg HFC-143a x 4800 * 3% = 1,730 kg CO₂-e
Note: Numbers may not add due to rounding.
The difference between Method A and Method B suggests that the leakage of refrigerant exceeds the default leakage rate, so improved maintenance of the refrigeration systems could help reduce leakage.
4.4 Medical gases use
This section covers emissions from medical gases. Anaesthetic medical gases can be a significant source of direct (Scope 1) emissions in hospitals. The most accurate way to calculate emissions from medical gases is based on consumption data.
4.4.1 Global warming potentials of medical gases
Table 4.3 details the GWPs of the medical gases included in this section (shown in kg CO2-e). The GWP is effectively the emission factor for each unit of medical gas lost to the atmosphere. The guide uses IPCC AR5 GWPs.
Some medical gases consist of a mixture (or blend) of gases. If you know the blend composition, you can calculate the GWP based on the percentage of each gas.
| Emissions Source | Unit | kg CO₂–e/unit |
|---|---|---|
| Medical Gases (AR5 GWPs) | ||
| HFE–347mmz1 (Sevoflurane) – (CF₃)₂CHOCH₂F | kg | 216 |
| HCFE–235da2 (Isoflurane) – CHF₂OCHClCF₃ | kg | 491 |
| HFE–236ea2 (Desflurane) – CHF₂OCHFCF₃ | kg | 1790 |
| Entonox – N2O/O2 (57.9/42.1) | kg | 153.435 |
4.4.2 GHG inventory development
To calculate medical gas emissions, collect consumption data for each medical gas used by the entity, and multiply this by the GWP for each gas.
\[ \begin{aligned} \text{Gas used (kg)} \times \text{GWP} &= \text{Emissions (kg CO}_{2}\text{-e)} \end{aligned} \]
Medical gases are supplied in bottles or cylinders. If only the volume of the gas is known, an additional calculation to calculate the mass of the gas is required to estimate emissions. This should be done by multiplying the volume (L) of gas by its density (g/mL or kg/L).
4.4.2.1 MEDICAL GAS USE: EXAMPLE CALCULATION
An entity uses 5 bottles of Isoflurane (HCFE-235da2, AR5 GWP = 491) in the reporting period. Each bottle holds 0.3 kg of Isoflurane. Its direct (Scope 1) emissions are:
5 bottles x 0.3 kg = 1.5 kg
Total CO2-e emissions = 1.5 x 491 = 736 kg CO₂-e
An entity uses 5 250 mL bottles of Isoflurane (HCFE-235da2, AR5 GWP = 491) in the reporting period. The density of Isoflurane is 1.49 g/mL. Its direct (Scope 1) emissions are:
5 bottles x 250 mL x 1.49/1,000 = 1.86 kg
Total CO2-e emissions = 1.86 x 491 = 913 kg CO₂-e
Note: Numbers may not add due to rounding.
4.4.3 Assumptions
This approach assumes that all anaesthetic gases used are eventually emitted, including the gases inhaled by patients.