Following this talk, several colleagues across the\u00a0Faculty\u00a0took the decision to increase their ULT freezer temperatures.\u00a0Among the early adopters of the Chill Up movement are:\u00a0<\/p>\n
- \n
- Stuart Pepper,<\/b>\u00a0Chief Laboratory Officer at the Cancer Research UK (CRUK) Manchester Institute, who led the adjustment of 55 out of 61 ULT freezers from \u201380\u202f\u00b0C to \u201370\u202f\u00b0C.\u00a0<\/li>\n
- Lydia\u00a0Wunderley,<\/b>\u00a0Gold LEAF Champion in the Woodman Lab, who coordinated temperature\u00a0adjustments across\u00a05 ULTs\u00a0in\u00a0a shared freezer farm.\u00a0<\/li>\n
- Nisha Nair<\/b>, Environmental Sustainability Lead for the School of Biological Sciences and LEAF champion at the Centre for Musculoskeletal Research, who has raised\u00a0the temperatures of approximately 22\u00a0ULT\u00a0freezers within her group.\u00a0<\/li>\n<\/ul>\n
Before looking at outcomes\u00a0of the movement,\u00a0it\u2019s\u00a0useful to outline the reasons why labs chose to chill up in the first place.\u00a0<\/p>\n
1. It saves a significant amount of energy.<\/strong><\/p>\n
ULT freezers are among the most energy-intensive pieces of\u00a0equipment in the lab.\u00a0Based on a typical\u00a0four-bedroom\u00a0house consuming 11.2 kWh\/day in the UK, on average, ULTs set\u00a0to\u00a0\u201380\u00a0\u00b0C consume the equivalent of 1.2 homes.\u00a0Stuart\u2019s\u00a0measurements showed\u00a0that raising the temperature from \u201380\u00a0\u00baC to\u00a0\u201370\u00a0\u00baC generated\u00a0an average saving of\u00a02.7kWh per freezer per\u00a0day.<\/b>\u00a0Across\u00a0the 55\u00a0freezers, this\u00a0saving\u00a0is equivalent\u00a0to the\u00a0daily\u00a0consumption of\u00a013.3\u00a0four-bedroom\u00a0UK\u00a0homes<\/b>.\u00a0\u00a0<\/p>\n
Using less energy leads to obvious economic benefits, but more importantly,\u00a0it\u2019s\u00a0also better for the environment\u00a0and supports the University\u2019s carbon reduction goals.<\/p>\n
![\"\"](\"https:\/\/blogs.manchester.ac.uk\/bmh-sr\/wp-content\/uploads\/sites\/178\/2026\/05\/Picture1.png\")
Visual comparison of laboratory cold storage energy use at \u201320 \u00baC, \u201370 \u00baC and \u201380 \u00baC.<\/p><\/div>\n
2.\u00a0<\/strong>It aligns with the LEAF criteria\u00a0and the University\u2019s sustainability goals.\u00a0<\/strong><\/p>\n
The\u00a0University\u2019s\u00a0Environmental Sustainability\u00a0Strategy\u00a02023-28<\/a>\u00a0outlines a commitment\u00a0to have all labs achieve a\u00a0LEAF accreditation.\u00a0Several LEAF criteria\u00a0pertain to\u00a0freezers:\u00a0Criterion #24 for the\u00a0Silver\u00a0award\u00a0specifically\u00a0encourages raising freezer temperatures where possible.\u00a0\u00a0<\/p>\n
By embracing the Chill Up movement, labs\u00a0move closer to a\u00a0LEAF accreditation and directly contribute to the University\u2019s sustainability goals.<\/p>\n
3. The standard used to be\u201370 \u00b0C.<\/strong><\/p>\n
According to\u00a0Lydia,\u00a0all the professors in\u00a0her\u00a0lab\u00a0area\u00a0recalled\u00a0a time when\u00a0\u201370 \u00b0C\u00a0was the typical setting for ULT freezers.\u00a0The later shift to \u201380 \u00baC was not due to new evidence on sample stability, but\u00a0simply\u00a0because\u00a0manufacturers\u00a0began producing freezers capable of reaching lower temperatures.\u00a0<\/p>\n
This means that returning to \u201370 \u00b0C is not a new compromise, but rather a return to\u00a0a previous, well-established standard\u00a0for\u00a0a wide variety of\u00a0samples.\u00a0<\/p>\n
However, samples are\u00a0ultimately precious, and decisions around freezer temperatures should always align with LEAF\u2019s first principle:\u00a0do not waste experiments and be guided by data.\u00a0<\/b>Reassuringly, there\u00a0is a large, long-term inventory study from the University of Colorado Boulder\u00a0that supports sample storage at \u201370 \u00baC\u00a0(Bousema et al., 2020<\/a>).\u00a0This work draws on data from laboratories that have operated ULTs at \u201370 \u00baC for over a decade, with no observed negative impact on a wide range of biological samples.\u00a0<\/p>\n
Within FBMH,\u00a0May\u00a0Tassabehji\u00a0<\/b>is also leading a similar long-term project to examine the integrity of less conventional samples at different cold storage temperatures.\u00a0While the results of this work are still\u00a0emerging, it is helpful to look at the experiences of those who have already implemented Chill Up in their labs.\u00a0<\/p>\n
Have labs experienced any issues after increasing ULT freezer temperatures?\u00a0<\/h3>\n
Almost two years after\u00a0the\u00a0initial\u00a0chill up movement, we asked Stuart,\u00a0Nisha\u00a0and Lydia to\u00a0comment on their observations so far.\u00a0Overall,\u00a0they\u00a0reported\u00a0very few issues\u00a0<\/b>after raising ULT freezer temperatures.\u00a0<\/p>\n
Stuart (CRUK Manchester Institute)\u00a0<\/h4>\n
Following the temperature increase, Stuart reported\u00a0no noticeable operational impact<\/b>\u00a0and no increase in false positive alarms, equipment\u00a0faults\u00a0or staff concerns.\u00a0<\/p>\n
It is of note that he has also led work to enable the storage of Human Tissue Act (HTA) samples at higher temperatures. Approximately 20 of the ULT freezers in the CRUK Manchester Institute\u00a0contain\u00a0such samples, including solid (normal and tumour) samples,\u00a0serum\u00a0and other fluids. However, not\u00a0all of\u00a0these freezers have been turned up to \u201370 \u00baC, as discussed below.\u00a0<\/p>\n
Lydia (Woodman Lab)\u00a0<\/h4>\n
![\"\"](\"https:\/\/blogs.manchester.ac.uk\/bmh-sr\/wp-content\/uploads\/sites\/178\/2026\/05\/Lydia-freezer-300x225.jpeg\")
A chest freezer in the Woodman Lab. It is fully racked with a full inventory kept in a folder on top of the freezer for easy access.<\/p><\/div>\n
All five freezers in the shared freezer farm of Lydia\u2019s lab area\u00a0were adjusted to \u201370 \u00baC by a lab technician in their group, making the transition quick and straightforward. These freezers\u00a0mainly store\u00a0recombinant proteins and competent\u00a0Escherichia coli<\/i>\u00a0bacteria.\u00a0\u00a0<\/p>\n
The only issue Lydia noticed is that\u00a0cells that\u00a0<\/b>should have been\u00a0<\/i><\/b>transferred to liquid nitrogen promptly after storage in the freezer showed increased cell death upon thawing.<\/b>\u00a0<\/p>\n
However, the issue highlights the importance of\u00a0appropriate storage\u00a0practices and\u00a0doesn\u2019t\u00a0reflect a problem with the chill up movement itself.<\/p>\n
Nisha (Centre for\u00a0Musculoskeletal\u00a0Research)\u00a0<\/h4>\n
Nisha\u2019s lab group primarily stores human-derived samples at \u201370 \u00baC. This includes\u00a0DNA, serum, plasma, urine, buffy coat,\u00a0<\/b>and\u00a0blood tubes.<\/b>\u00a0<\/p>\n
They have not\u00a0observed\u00a0clear negative effects since switching, but the differences are difficult to tell due to several reasons:\u00a0<\/p>\n
- \n
- Some samples have been stored for many years, making changes difficult to attribute.\u00a0<\/li>\n
- There are other confounding factors such as\u00a0freezer failures\u00a0<\/b>and decanting samples to another freezer.\u00a0\u00a0<\/li>\n
- Certain samples (e.g. serum) naturally lose viability with every freeze-thaw cycle, regardless of the storage temperature.\u00a0<\/li>\n<\/ul>\n
Does raising temperatures extend freezer life span?\u00a0<\/h3>\n
Although the Faculty\u2019s Chill Up movement is still in its\u00a0early stages, other organisations have been\u00a0operating\u00a0at higher freezer temperatures for many years, and their long-term data\u00a0provide\u00a0valuable\u00a0insight into whether\u00a0higher\u00a0temperatures\u00a0contribute to longer freezer life spans.\u00a0<\/p>\n
One example comes from\u00a0Julie Oxton<\/a>\u00a0and\u00a0Rob Oliver<\/a>\u00a0the\u00a0Salford Biorepository Facility (SBF)<\/a>\u00a0<\/b>at Salford Royal. They have\u00a0been running\u00a012 ULT freezers at \u201375\u202f\u00b0C for over 10 years, storing a wide range of HTA\u2011regulated human samples. Over this period, they report no adverse effects on their samples and noted that many of their freezers have\u00a0remained\u00a0operational for\u00a0more than 12 years.<\/b>\u00a0<\/p>\n
Experience within FBMH also suggests\u00a0that operating ULT freezers at higher temperatures may lead to extended lifespans, but other factors are also at play.\u00a0As Nisha noted, some freezers in her area have been in service for\u00a0nearly 20\u00a0years<\/b>, having\u00a0operated\u00a0at \u201380\u202f\u00b0C for much of that time. It is well established that regular annual maintenance\u00a0may be as important as\u00a0temperature\u00a0settings\u00a0in supporting\u00a0long\u2011term\u00a0freezer performance and reducing energy consumption (see\u00a0Ref 2)\u00a0<\/p>\n
What should labs consider before deciding to chill up?\u00a0<\/h3>\n
Despite the positive outlook,\u00a0there are still barriers that may prevent some\u00a0labs\u00a0from\u00a0joining in on the chill up movement.\u00a0Combining testimony from Stuart,\u00a0Lydia\u00a0and Nisha,\u00a0we\u2019ve\u00a0identified\u00a0several factors that labs may want to think about before\u00a0raising ULT freezer temperatures.\u00a0<\/p>\n
1. Regulatory and governance requirements\u00a0<\/b><\/p>\n
While Stuart had chilled up 55 out of 61 ULT freezers in the CRUK Manchester Institute, no progress has been made on the remaining freezers yet. These all\u00a0contain\u00a0HTA samples<\/b>, where regulatory requirements are more\u00a0complex\u00a0and the samples themselves are particularly precious. As a result, decisions around these freezers require closer engagement with HTA governance processes and\u00a0additional\u00a0reassurance before changes can be made.\u00a0<\/p>\n
Stuart has since discussed this with the Institute\u2019s HTA governance team, and progress is expected later this year, although no concrete changes have been implemented yet.\u00a0<\/p>\n
2. Sample type and viability<\/b><\/p>\n
Nisha noted that\u00a0many\u00a0labs would want to know whether their\u00a0specific\u00a0sample\u00a0types\u00a0will remain\u00a0viable\u00a0at the higher \u201370 \u00baC setpoint. Every lab works with different sample types,\u00a0with some more\u00a0temperature-sensitive\u00a0than others.\u00a0\u00a0<\/p>\n
Providing\u00a0sample-specific reassurance<\/b>\u00a0can therefore be\u00a0very helpful\u00a0in\u00a0building confidence\u00a0and encouraging adoption of\u00a0chill up across diverse research teams.\u00a0\u00a0<\/p>\n
Labs that would prefer\u00a0additional\u00a0reassurance or testing before chilling up may wish to connect with\u00a0May<\/a>\u00a0about\u00a0her long-term project\u00a0examining sample integrity at different cold storage temperatures.\u00a0<\/p>\n
3. Practical and operational considerations<\/b><\/p>\n
Some labs may\u00a0worry about the time and effort\u00a0required\u00a0to adjust multiple ULT freezers.\u00a0Nisha suggested a practical solution to this:\u00a0ask your\u00a0maintenance engineer\u00a0<\/b>to change the temperatures during annual servicing.\u00a0This saves staff time while ensuring the adjustments are carried out correctly.\u00a0<\/p>\n
Beyond Chill Up:\u00a0Join the Freezer Challenge\u00a0<\/h3>\n
As the\u00a0testimonies above\u00a0demonstrate,\u00a0raising ULT temperatures\u00a0can be\u00a0both safe and impactful.\u00a0One opportunity to build on this momentum is to take part in\u00a0My Green Lab\u2019s<\/a>\u00a0international\u00a0Freezer Challenge<\/a>.\u00a0<\/p>\n
Through friendly competition, this challenge\u00a0encourages laboratories around the world to\u00a0improve their cold storage efficiencies\u00a0and\u00a0reduce running\u00a0costs.\u00a0While\u00a0the Chill Up movement\u00a0focuses on temperature settings, the Freezer Challenge\u00a0promotes\u00a0a wider set of good practices\u00a0aligned with the LEAF criteria:\u00a0\u00a0<\/p>\n
- \n
- Ensure freezer alarms are working via regular battery checks.\u00a0\u00a0It is paramount to ensure we protect our freezer content with functioning alarm systems.\u00a0\u00a0<\/li>\n
- Reduce door-open time\u00a0<\/li>\n
- Keep an\u00a0up-to-date\u00a0inventory\u00a0<\/li>\n
- Use\u00a0rack space efficiently and declutter\u00a0regularly\u00a0<\/li>\n
- Defrost\u00a0freezers and clean filters\u00a0regularly\u00a0[why don\u2019t you try our wet\u00a0dry\u00a0hoovers?]\u00a0<\/li>\n
- Retire\u00a0unnecessary units\u00a0<\/li>\n
- Store samples at the right temperatures\u00a0<\/li>\n<\/ul>\n
Support is available across the\u00a0Faculty\u00a0to help with some of these actions. For example,\u00a0wet-dry hoovers can be borrowed\u00a0to make freezer defrosting quicker and easier.\u00a0<\/p>\n
The competition takes place\u00a0virtually between\u00a0January and June every year, and it offers an easy yet structured framework to improve lab sustainability.\u00a0Find out more about the Freezer Challenge by\u00a0visiting the My Green Lab website<\/a>\u00a0or\u00a0watching this promotional video from King\u2019s College London.<\/a>\u00a0<\/p>\n
Additional Information\u00a0<\/h3>\n
Further\u00a0reading:<\/b>\u00a0<\/p>\n
- \n
- ULT Freezers: Why -70C isn’t as scary as it seems<\/a>\u00a0(PowerPoint presentation on the benefits of raising ULT freezer temperatures)\u00a0<\/li>\n
- Unveiling the Optimal Temperature: A Comprehensive Literature Review on Biological Sample Storage in ULT Freezers<\/a>\u00a0(Exeter University)\u00a0<\/li>\n<\/ol>\n
If you want to explore potential savings in your own lab, plug-in energy meters are now\u00a0available for loan at several FBMH buildings.\u00a0Find out more\u00a0about the plug energy meters campaign.<\/a>\u00a0<\/p>\n
A University-wide LEAF SharePoint site is now available, acting as a central space for\u00a0guidance, support contacts,\u00a0resources\u00a0and case studies.\u00a0Find out more\u00a0about the LEAF SharePoint launch.<\/a>\u00a0<\/p>\n
To find out more about Environmental Sustainability in FBMH, visit the\u00a0Faculty\u2019s\u00a0intranet page<\/a>,\u00a0website<\/a>\u00a0or contact\u00a0srbmh@manchester.ac.uk<\/a>.\u00a0<\/p>\n
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Related<\/h1>\n
Related posts:<\/h3>
- Unveiling the Optimal Temperature: A Comprehensive Literature Review on Biological Sample Storage in ULT Freezers<\/a>\u00a0(Exeter University)\u00a0<\/li>\n<\/ol>\n
- ULT Freezers: Why -70C isn’t as scary as it seems<\/a>\u00a0(PowerPoint presentation on the benefits of raising ULT freezer temperatures)\u00a0<\/li>\n
- Certain samples (e.g. serum) naturally lose viability with every freeze-thaw cycle, regardless of the storage temperature.\u00a0<\/li>\n<\/ul>\n
- Lydia\u00a0Wunderley,<\/b>\u00a0Gold LEAF Champion in the Woodman Lab, who coordinated temperature\u00a0adjustments across\u00a05 ULTs\u00a0in\u00a0a shared freezer farm.\u00a0<\/li>\n