HeyReader, how many freezers are in your institute?
Cooling units play a major role in sustainability.
Therefore, we will deliver you the very first complete freezer guide!
To keep it digestible, we split it into 3 parts. Read them all and you will be even better equipped than most sustainability managers!
Today, we will look at overall impacts and answer the question: Should you replace your old freezers?
Today's Lesson: Freezer & Fridge Impacts
Assessing the environmental impact of cooling
Number Of The Day
The Refrigerant R508A has a global warming potential (GWP100) of 13,419. In other words, over 100 years, its heat-trapping effect is 13 419 times stronger than carbon dioxide. For comparison, Methane has a GWP100 of 27, Nitrous oxide has a GWP100 of 273. R508A is a mixture of hexafluoroethane and trifluoromethane, whereas other refrigerants consist of a single compound (e.g., R290 – propane, R134a – tetrafluoroethane).
13419
The Impact of Fridges and Freezers
To this day, there is not a single comprehensive life cycle analysis available for a -80°C ultra-low temperature (ULT) freezer. The same goes for lab fridges.
Such a common view, and yet so little data. Indeed, to estimate the footprints reported herein, data from domestic, laboratory and commercial cooling units (fridges, "cupboards", walk-in and freezers) was pulled together. Additional information in our free Slack.
Therefore, I went through the available data and, where necessary, translated findings from commercial fridges to our situation. Although tedious, the data was surprising:
Manufacturing Impact
A typical household fridge weighs 60–150 kg and is made from a wide range of materials, including stainless steel, aluminum, copper, polystyrene, tempered glass, acrylics, and polyurethane foam.
Average Fridge Composition: The main non-ferrous metal are aluminum and copper. Plastics are mainly synthetic rubber, polystyrene ,ABS, PVC and polyurethane foam. The data comes from her.
The carbon footprint of manufacturing such a fridge is around 200–800 kg CO₂e. Walk-in refrigeration units or those used in supermarkets have accordingly higher impacts.
Lab freezers, are somewhat heavier: a 500 L -80°C freezer weighs 240–340 kg, meaning its estimated manufacturing footprint is 600–900 kg CO₂e.
As we will discuss later in more detail, 700+L freezers consume about 20-60% more energy than their 500+L counterparts (dependend on manufacturer).
Interestingly, larger 700+ L models weigh roughly the same (260–315 kg), resulting in a similar manufacturing footprint.
Energy Consumption – The Biggest Factor
Most of a freezer’s footprint comes not from its production but from its electricity use. The ongoing impact is as follows:
Household fridge:
1–2 kWh/day → 0.64 kg CO₂/day
77–234 kg CO₂/year
Please note that this is data for domestic models taken from this paper.
-80°C freezers (500+L, assuming 341 g CO₂/kWh in Germany):
Very old model: 36 kWh/day → 4,480 kg CO₂/year
Newer model: 12 kWh/day → 1,493 kg CO₂/year
Best model available: 7 kWh/day → 871 kg CO₂/year
Of note, these are compressor-based fridges—i.e., they use a compressor for cooling. For -70/-80°C, these are the most common models. However, some units use liquid nitrogen (especially for -130°C) for cooling, resulting in a very different life cycle composition.
Refrigerants
In short, a refrigerant is a substance used in cooling systems to absorb and release heat, enabling refrigeration and air conditioning.
It cycles through phase changes (liquid ↔ gas) to transfer heat efficiently.
Why does this matter? Because refrigerants have an enormous climate impact when leaked. For instance, assuming a 50% refrigerant recovery during disposal:
A small -20°C freezer (R134a) → 71.5–143 kg CO₂e impact at disposal
A -80°C freezer (R404 & R508) → 2,000–3,631 kg CO₂e impact at disposal
Due to a 2–15% leakage rate per year, full recovery is impossible, and occasional refilling is required. On top of that, illegal disposal and improper handling remain widespread.
End-of-Life
The end-of-life impact, including disposal, plays a smaller role in the overall footprint.
Estimates range between 0.25–15 kg CO₂e. (Deeper discussion about potential false assumptions in our Slack)
Transportation to the landfill is likely a significant contributor. Additionally, we need to account for the energy consumption of hulk shredding (approx. 144 J/kg) and material separation.
Typical recycling rates look something like steel, aluminum, and copper: Recycled at 37%, 32%, and 22% by weight, respectively. Plastics and residue: 20% incinerated, 80% landfilled.
Applying The Knowledge
A fridge has a total footprint of about 2000-8000 kg CO₂e over a 10-year lifespan. For a -80°C freezer, that number is closer to 20 000– 50 000 kg CO₂e. (More in our free Slack).
This data refers to domestic fridges with a volume of 255L, weighing 63kg taken from Cappelletti et al.
Let’s summarize:
Financially: The cost of a new freezer amortizes over 5–10 years, depending on energy prices.
Environmentally: The footprint amortizes in 2–5 years due to massive energy savings.
Compared to a 500+L model, the 700+ L energy consumption increases by roughly 30%, meaning faster amortization in environmental terms.
Bottom line:
If your freezer is 15+ years old → Definitely replace it.
If your freezer is 10+ years old → Replacement is likely a good decision.
If your freezer is 5+ years old → Debatable, analysis recommended
Upcoming Lesson:
Energy Savings & Freezers
How We Feel Today
References
Kim, H.C., Keoleian, G.A., Horie, Y.A., 2006. Optimal household refrigerator replacement policy for life cycle energy, greenhouse gas emissions, and cost. Energy Policy, 34(15), 2310–2323. doi:10.1016/j.enpol.2005.04.004.
Glöser‐Chahoud, S., Pfaff, M., Schultmann, F., 2021. The link between product service lifetime and GHG emissions: A comparative study for different consumer products. J. Ind. Ecol., (), –. doi:10.1111/jiec.13123.
Cappelletti, F., Rossi, M., Germani, M., 2023. A dynamic approach for life cycle assessment: The case of domestic refrigerators. Proc. Des. Soc., 3, 131–140. doi:10.1017/pds.2023.14.
Cascini, A., Gamberi, M., Mora, C., Rosano, M., Bortolini, M., 2015. Comparative carbon footprint assessment of commercial walk-in refrigeration systems under different use configurations. J. Clean. Prod., (), –. doi:10.1016/j.jclepro.2015.08.075.
Velásquez-Rodríguez, O.F., Løvik, A.N., Moreno-Mantilla, C.E., 2021. Evaluation of the environmental impact of end-of-life refrigerators in Colombia by material flow analysis. J. Clean. Prod., (), –. doi:10.1016/j.jclepro.2021.127884.
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