Published Date: 07/10/2026
Category: ESG
Read Time: 4 minutes
What do Glasgow's weather and data centre efficiency have in common?
Quite a lot, as it turns out.
This summer, we completed a £1.3 million upgrade to the cooling infrastructure at our Glasgow DC1 data centre - replacing an ageing system with new technology designed to make the site more efficient, more resilient and more sustainable.
And part of the answer lies just outside the building.
Our new Direct Expansion (DX) cooling system incorporates free cooling, which means that when Glasgow's famously cool outside temperatures allow, we can reduce our reliance on energy-intensive mechanical cooling.
It's a relatively simple idea with the potential to make a significant difference.
The new equipment is expected to save around 34,000kg of CO₂ each year, while the project is forecast to deliver approximately £2.8 million in energy cost savings over its 15-year lifecycle.
Better still, we're already beginning to see the impact.
Because working and working efficiently aren't always the same thing.
The existing cooling system at DC1 had reached the end of its economic life. As the equipment aged, it had become less efficient, more expensive to maintain and increasingly prone to breakdowns.
We knew it needed replacing. But rather than simply swapping old equipment for a newer version of the same thing, we saw an opportunity to rethink how we cool the site altogether.
The goal was to create a system that could use less energy, cost less to operate and maintain, and give our teams greater visibility and control - all while maintaining the resilience our customers depend on.
Despite the name, it doesn't mean cooling a data centre without using any energy.
Instead, free cooling takes advantage of naturally cooler external conditions to reduce the amount of mechanical refrigeration needed to maintain the right temperature inside the data centre.
When outside temperatures are suitable, the system can make greater use of those cooler conditions. When they're not, mechanical cooling takes over.
And if you're thinking Scotland sounds like a pretty good place for that, you'd be right.
Our climate gives us plenty of opportunity to make use of cooler ambient temperatures throughout the year, reducing the energy needed for cooling without compromising the controlled environment our customers' infrastructure needs.
Replacing the cooling system was one thing.
Replacing the cooling system supporting a live data centre, without disrupting the businesses relying on it, was another.
That was one of the biggest challenges facing the team.
The project involved completely replacing DC1's air-conditioning infrastructure while maintaining site resilience and ensuring there was no discernible impact on customer operations.
With a project of this scale, there are plenty of moving parts and dependencies that can affect delivery. But the work remained on schedule throughout and was completed as planned this summer.
That's something the team behind it is rightly proud of.
There was another challenge waiting for us when the new system became fully operational: the weather.
The system went live during a prolonged warm spell - not exactly ideal conditions for demonstrating the benefits of using cooler ambient temperatures.
Even so, we've already seen significant reductions in DC1's Power Usage Effectiveness (PUE), a key measure of how efficiently a data centre uses energy.
As temperatures fall and the system has more opportunity to use free cooling, we'll be able to build an even clearer picture of its impact.
The technology behind it is smarter, too.
Advanced digital monitoring, capacity control and performance reporting give our teams greater visibility into how the cooling infrastructure is performing. That should help us reduce maintenance requirements, improve reliability and manage the site more efficiently over the long term.
The project represents a £1.3 million investment in our Glasgow infrastructure, with £297,291 funded through the Scottish Industrial Energy Transformation Fund (SIETF) 2025-26.
And the benefits aren't just environmental.
Over the plant's expected 15-year lifecycle, we're forecasting approximately £2.8 million in energy cost savings, with an estimated return on investment of around 3.5 years.
At the same time, the new infrastructure gives us a more scalable and adaptable cooling platform that can support the future needs of DC1 as technology - and our customers' requirements - continue to evolve.
For us, that's what meaningful investment in sustainability should look like.
It's not about sustainability sitting separately from resilience, performance or commercial decisions. The best investments improve all of them.
It's easy to think of the cloud as something intangible.
But every workload, application and piece of data ultimately depends on physical infrastructure somewhere. Data centres need power. They need cooling. They need resilient systems that can keep running around the clock.
So making cloud infrastructure more sustainable also means looking closely at the less visible parts of a data centre and asking: could this work better?
At DC1, the answer was yes.
Paul Sewell, Data Centre Director at Iomart, said:
“Replacing the cooling infrastructure across a live data centre was a significant undertaking. Our priority throughout was to improve the efficiency and long-term resilience of DC1 without compromising the service our customers rely on.
The team delivered the entire project to schedule with no discernible impact on customer operations. To already be seeing improvements in PUE, despite the system becoming fully operational during a prolonged warm spell, is a really positive indication of the impact this investment will have.”
Our customers probably won't notice the new cooling system at DC1.
And that's exactly how it should be.
What they will continue to get is the resilient infrastructure they depend on - only now, there's a smarter and more efficient system working behind the scenes to support it.
