Why chillers fail when the temperature hits 25°C

When people compare chillers, they usually look at:

• Cooling capacity
• Power rating
• Price
• Litres it's rated for

Makes sense — it's what you have access to.

But here's what's rarely mentioned:

Most of those specs are rated in 20°C ambient air. In factory-controlled conditions.

Not in an Australian summer. Not next to a sauna. Not in a facility pumping out 60 plunges an hour.

Ambient temperature changes everything.

On the hotter days, two main things change.

The amount of heat being pushed into the pools increases, so the chiller has to work harder, but the efficiency by which the chiller can remove the heat drops with every degree increase.

So the work load increases and the capacity of the chiller decreases.

It impacts:

• How hard the chiller has to work
• How much heat it has to remove from the water and the air
• How long it takes to recover between sessions
• Whether it ever reaches target temp at all

Here's what that looks like in numbers.

A chiller rated at 10kW in factory conditions might only deliver 4-6kW of actual cooling when the ambient air hits 40°C. Same unit, same day, 40-60% less performance.

The pool that stayed at 7°C all winter starts creeping up to 10°C, then 12°C, then struggles to get below 15°C no matter how long the chiller runs.

Most people discover this the hard way.

The unit that looked perfect on paper becomes the bottleneck in your operation. Sessions that should recover in 10 minutes take 25. Peak hours become a problem. Client experience suffers.

This is why ambient conditions matter more than the spec sheet.

When you're evaluating systems, the question isn't just "How many kW?"

It's "How many kW at the ambient temperature you'll actually face?"

That number tells the real story.