Sonia Holzheimer: role change, and reflecting on the HVAC&R profession

In a LinkedIn post, Holzheimer explains that stepping away from her role of founder and co-Director at SEQUAL was a significant shift. However, with some of the team at SEQUAL preparing for retirement, the time was right to make a move.

She says that STP offers things she values: a network of regional offices, where a small firm is “duplicated into something bigger”.

“The sum is greater than its parts. We are local engineers who choose to live here — invested in this community, with the local knowledge that runs deep. That matters to me enormously.”

The company has seven offices across the state, delivering solutions across Structural, Civil, Mechanical, Electrical, Hydraulic, Fire, Seismic, Section J, and Vertical Transport disciplines.

Holzheimer will be putting her “heart and soul into delivering the best HVAC services I can.”

She observes that while some organisations such as banks have been pulling back from the regions; others, such as STP, have “bucked the trend and invested in them instead”.

That’s really important to her as AIRAH’s Queensland Division Associate Director.

“Queensland is a huge state, and I see it as part of my role to help keep the focus on the regions, not just the highly populated south-east corner. My move to STP wasn’t created or driven for that purpose, but I do think it will better support my work as Queensland Division AD,” she says.

“As a partner with STP, I’ll have the opportunity to contribute across the state rather than maintaining a predominantly Cairns-focused perspective, while still remaining proudly based in the far north.”

In the lead-up to World Refrigeration Day, HVAC&R News asked her for some thoughts about what makes HVAC&R so important to society, and the ways she sees human intelligence shine in the sector.

HVAC&R News: What do you think are some of the coolest things human intelligence has achieved in terms of refrigeration?

Holzheimer: I’m not a palaeontologist, but I imagine our ancestors worked out pretty quickly that food kept somewhere cold, a cave, a rock crevice, a hole in the ground, lasted longer than food left out in the open. Long before we understood microbiology or thermodynamics, we understood one simple thing: colder food stayed safe to eat for longer. That knowledge was a survival advantage.

Cooking changes the storage time too, but that’s another rabbit hole.

What fascinates me is what happened next.

At some point we stopped just looking for cold places and decided to make our own. That’s a very human trait. We don’t accept the conditions nature gives us; we figure out how to change them. We engineer them.

The clever part is this: refrigeration isn’t really about creating cold – it’s about moving heat. Heat flows naturally from hot to cold.

We worked out that if you move enough heat out of a space, you can make it really cold. Refrigeration is the physics of moving heat from where we don’t want it to somewhere ‘else’.

So, one of our greatest engineering achievements wasn’t learning to make things cold. It was understanding the natural direction heat travels, then building the conditions to get the result we wanted. We hacked the system.

To me, that’s cool human intelligence.

HVAC&R News: What are some of the personal qualities that are required by engineers and technicians in refrigeration?

Holzheimer: Engineers and technicians need only the most basic and human of traits. The curiosity to understand something, and the drive to make it better. Or more accurately, the drive to make it less bad.

In my experience people are quick to tell you what they don’t like. We move away from pain way faster than we move toward pleasure, and it’s the same with everything. We’re sharp about what bothers us and a bit ‘meh’ about what already works.

To understand any of it and more importantly in order to figure out how to make something better you need the foundations of STEM. So, engineers and technicians just need the basic traits we already have as humans, plus knowledge of STEM to apply it.

HVAC&R News: What are some things humans in HVAC&R do that AI can never replace?

Holzheimer: To me, AI is a desk tool, same as my computer. The hands-on side I’ll leave to the technicians.

AI is going to change HVAC&R, no question. It’ll get very good at crunching data, optimising systems and spotting patterns we’d miss. A lot of the desk-type engineering work I do now, it’ll do faster. But it’s still a tool, and like Excel or a heat load calculation, rubbish in equals rubbish out. We need to be careful about the faith we put in it.

Our ability to see through an AI answer, the spider sense that tells you something’s “off”, only comes from grunt work. The maths. The calculations. The hours on tools like heat load software, watching how the inputs move the outputs.

I can see the day coming when we just ask AI for the size and capacity. Even then, we’ll need that spider sense for when it’s wrong. And at some point, it will be wrong.

That awareness only comes from doing it the hard way (or the long way). I have a feel for heat loads because I’ve done so many. If it was my first day on the job and the robot handed me a required capacity, I’d have no way of knowing whether it was right or wrong.

That’s what I think AI can’t replace. The gut feel. Your engineering spidey-sense.

Then there’s judgement. Judgement is knowing what matters. It’s telling the robots what to focus on and what to ignore, which constraint wins when two are in tension, when good enough is actually good enough, and when it isn’t. AI can give you an answer, but it may not be one that really matters for you.

And that brings me to care. Care is why any of it matters. It’s checking the work because someone is relying on what you sign off, whether that’s about comfort, or health, or a building requirement. Care is the part that makes you go back and look again and check, even though it would be easier not to.

Main Image: Sonia Holzheimer out exploring the Tropical North.
She says, “If you’ve never been to Cairns, come and experience it for yourself at IAQ26.”

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