Personal Note From Patrick, The Editor

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?

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.

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.

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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.

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Interestingly, larger 700+ L models weigh roughly the same (260–315 kg), resulting in a similar manufacturing footprint.

Of note, two papers I could find tried to assess the footprint of freezers directly.

​Graham et al. got a list of components that comprise an Eppendorf F570n ULT freezer and used the Inventory of Carbon and Energy database (version 3.0) to estimate a manufacturing footprint of about 1099kg.

​Berchowitz et al. estimated the cradle-to-gate embodied carbon footprint of a conventional cascade ultra-low-temperature freezer at approximately 7.1 t CO₂e per unit, compared with approximately 2.3 t CO₂e for a Stirling-cooled freezer.

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

-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.

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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).

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.
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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.
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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.
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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.
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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.

Added:

Graham, M., et al., 2024. Roadmap for low-carbon ultra-low temperature storage in biobanking. Journal of Translational Medicine, 22(1), 747. doi:10.1186/s12967-024-05383-5.

Berchowitz, D.M., et al., 2012. Environmental profiles of Stirling-cooled and cascade-cooled ultra-low temperature freezers. Sustainability, 4(11), 2838–2851. doi:10.3390/su4112838.

If you have a wish or a question, feel free to reply to this Email.
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Otherwise, wish you a beatiful week!
See you again the 20th : )

Find the previous lesson click - here -​

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Edited by Patrick Penndorf
Connection@ReAdvance.com
Lutherstraße 159, 07743, Jena, Thuringia, Germany
​Data Protection & Impressum​
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