| Scenario | t CO2e | GWP | Note |
|---|
How to Use the Refrigerant GWP Calculator
Select the refrigerant in the system, or pick Custom and enter a GWP, and choose kilograms or pounds for the charge.
Enter the system charge, the annual leak rate, the service life in years and the share of the charge recovered at end of life.
Choose up to three alternative refrigerants. If the replacement unit holds a different charge, enter it as a percentage of the current charge.
Press Calculate GWP and Emissions to see the annual, full-charge and lifetime tonnes of CO2e, the bar comparison and the scenario table.
Refrigerant GWP, leak emissions and the Canadian rules
Global warming potential turns a mass of refrigerant into the carbon dioxide that would warm the climate by the same amount. For a technician or an owner, it answers a practical question: what do this charge, this leak rate and this end-of-life plan cost the climate, and how much would a different refrigerant change that?
What GWP measures and where the values come from
GWP compares the warming from 1 kg of a gas over 100 years with the warming from 1 kg of CO2, so a GWP of 1,430 for R-134a means each kilogram released does the work of 1,430 kg of CO2. The calculator uses the 100-year values from Table 2.14 of the IPCC Fourth Assessment Report: 675 for HFC-32, 3,500 for HFC-125, 1,430 for HFC-134a and 4,470 for HFC-143a. Canada's Ozone-depleting Substances and Halocarbon Alternatives Regulations list the same values for HFC-32 and HFC-125. A blend takes the mass-weighted sum of its parts. R-410A is half R-32 and half R-125, so 0.5 x 675 + 0.5 x 3,500 gives 2,087.5, which rounds to 2,088. R-454B, at 68.9% R-32 and 31.1% R-1234yf, works out to 466. The AR4 table has no entry for propane or the HFOs, so R-290 and R-1234yf carry the values commonly published for them, 3 and 4, which barely move any result.
| Refrigerant | Composition by mass | ASHRAE class | GWP (AR4) |
|---|---|---|---|
| R-410A | R-32 50% / R-125 50% | A1 | 2,088 |
| R-32 | R-32 | A2L | 675 |
| R-454B | R-32 68.9% / R-1234yf 31.1% | A2L | 466 |
| R-404A | R-125 44% / R-143a 52% / R-134a 4% | A1 | 3,922 |
| R-448A | R-32 26% / R-125 26% / R-1234yf 20% / R-134a 21% / R-1234ze(E) 7% | A1 | 1,387 |
| R-449A | R-32 24.3% / R-125 24.7% / R-1234yf 25.3% / R-134a 25.7% | A1 | 1,397 |
| R-452A | R-32 11% / R-125 59% / R-1234yf 30% | A1 | 2,140 |
| R-22 | R-22 | A1 | 1,810 |
| R-407C | R-32 23% / R-125 25% / R-134a 52% | A1 | 1,774 |
| R-134a | R-134a | A1 | 1,430 |
| R-507A | R-125 50% / R-143a 50% | A1 | 3,985 |
| R-513A | R-1234yf 56% / R-134a 44% | A1 | 631 |
| R-450A | R-134a 42% / R-1234ze(E) 58% | A1 | 605 |
| R-422D | R-125 65.1% / R-134a 31.5% / R-600a 3.4% | A1 | 2,729 |
| R-290 | Propane | A3 | 3 |
| R-744 | Carbon dioxide | A1 | 1 |
| R-1234yf | R-1234yf | A2L | 4 |
How leak and end-of-life emissions add up
Three inputs drive the result. Annual leakage is the charge times the leak rate, and it repeats every year of the service life on the assumption that lost refrigerant is topped up so the system keeps running. At end of life, whatever is not recovered is released, which is the charge times one minus the recovery rate. Add those masses and multiply by the GWP to get tonnes of CO2e. In the Commercial Example, 10 kg of R-404A leaking 15% a year for 12 years loses 18 kg, and with 80% recovered at the end another 2 kg escapes, so 20 kg at a GWP of 3,922 gives 78.44 t CO2e. The same mass of R-448A (GWP 1,387) totals 27.74 t, which is 65% lower.
Comparing refrigerants that need a different charge
Changing refrigerant rarely means the same mass in the system. A replacement unit may carry a different charge, so the Alternative Charge field takes the replacement's nameplate charge as a percentage of the current charge. Leave it at 100% only for a like-for-like comparison. Every alternative shares the leak rate, service life and recovery rate you enter, which is a simplification, because a new sealed system may leak less than a 15-year-old one. Run the numbers twice with different leak rates to see how much that matters.
Canada's HFC phase-down
Canada caps HFC consumption in tonnes of CO2e, which is why GWP is the number that counts. The baseline is 18,008,795 t CO2e, made up of the 2011 to 2013 average HFC consumption plus a 15% HCFC component. The cap steps down to 10% below baseline in 2019, 40% in 2024, 70% in 2029, 80% in 2034 and 85% in 2036, when allowed consumption falls to 2,701,319 t CO2e. The cap applies to the companies that import or manufacture HFCs, not to the contractor, but it shapes which refrigerants stay available. For the compliance side of the schedule, try the HFC phase-down calculator.
Leak tests and records in Canada
The Federal Halocarbon Regulations, 2022 set the day-to-day rules. A system that holds, or is designed to hold, more than 10 kg of halocarbon needs a leak test by a certified person at least once every calendar year and no more than 15 months after the previous one. A leak in a system of any size has to be repaired, or the refrigerant recovered, by a certified person no later than seven days after it is found. Documents stay on site for at least five years. The results panel tells you which side of the 10 kg line your charge falls on. R-290 and R-744 are not halocarbons, so these rules are not the ones that apply to them, and provincial requirements may add to the federal ones.
Reporting refrigerant emissions as Scope 1
Under the GHG Protocol, refrigerant that leaks from equipment you own or control is a Scope 1 fugitive emission. The usual measure comes from service records: the refrigerant added to a system to replace losses, multiplied by the GWP, gives the year's tonnes of CO2e. This calculator's annual figure is a forecast from an assumed leak rate, so swap in the real top-up quantity once a year of records exists, and weigh every cylinder in and out to support it. To write the totals up, try the carbon report generator.
Direct emissions are only part of the warming impact
Total equivalent warming impact, or TEWI, adds the indirect emissions from the electricity a system uses to the direct refrigerant emissions this calculator reports. A low-GWP refrigerant in a less efficient system can lose its advantage on a carbon-heavy grid, while on a low-carbon grid the direct leak emissions can make up a larger share of the total. Check efficiency with the COP calculator before you judge a refrigerant on GWP alone.
Frequently Asked Questions
Multiply the mass released by the refrigerant's GWP and divide by 1,000 to get tonnes of CO2e. The Commercial Example uses 10 kg of R-404A (GWP 3,922) leaking 15% a year. That is 1.5 kg a year, or 5.88 t CO2e, about 1.37 passenger vehicles driven for a year. Over 12 years the leakage is 18 kg, and with 20% of the charge vented at end of life the lifetime total is 78.44 t CO2e.
It uses 100-year GWP values on the IPCC Fourth Assessment Report (AR4) basis, for example 2,088 for R-410A, 675 for R-32 and 3,922 for R-404A. Blend values are the mass-weighted sum of their components. The AR4 table has no entry for propane or the HFOs, so R-290 (3) and R-1234yf (4) use the values commonly published for them. Later assessment reports give different numbers, so choose Custom and enter the value if a report or a customer needs another basis.
On the values used here, yes. A 1 kg leak of R-290 is 3 kg CO2e, against 3,922 kg CO2e for R-404A, about 1,307 times less. At the same 10 kg charge, the Commercial Example gives 0.060 t CO2e over the life for R-290 against 78.44 t for R-404A. R-290 is class A3, highly flammable, so the charge a system may hold is set by the equipment standard and the code, not by GWP. Enter the real nameplate charge in the Alternative Charge field.
Enter the replacement's nameplate charge as a percentage of the current charge in the Alternative Charge field. The Residential Example compares 2.5 kg of R-410A (GWP 2,088), leaking 5% a year for 15 years, with 80% of that charge, 2.0 kg, of R-454B (GWP 466). The R-410A system totals 4.96 t CO2e and the R-454B system 0.885 t, which is 82% lower. R-32 at the same 2.0 kg totals 1.28 t, 74% lower.