Home › Insights

Air or liquid cooling: how to decide for your next data hall

By Jay, Founder of G2MAX · Updated 2026-10-30

Short answer: air still suits most halls at moderate rack density, and it's what operations teams know. Liquid carries far more heat per unit volume, and becomes the practical choice as density rises. There's no single kW-per-rack switch-over point; it depends on the hall. Many new designs end up hybrid: liquid where density needs it, air for the rest. What decides it is your density plan, water and climate, team and power.

Side by side

	Air	Liquid (cold-plate or immersion)*	Hybrid
Familiar to most ops teams	Yes	Less so	Partly
Handles high density	Limited	Yes	Yes, where needed
Retrofit into existing hall	Easy, if density stays within existing cooling capacity	Harder: piping, floor loads, leak management	Possible in zones
Heat rejection temperature	Lower	Higher, which extends dry-cooler and economiser hours (less so in Gulf summers)	Mixed
Supply chain and spares	Mature	Still maturing	Both

*Cold-plate and immersion are quite different. Floor-load and fluid-handling questions are mostly an immersion issue, and cold-plate systems still reject part of the heat to air, so in practice they are hybrid.

The questions that decide it

1. What density will you run in years one to three, not year ten? Design for that, leave pathways for more.
2. What's your climate and water situation? In the Gulf, water and ambient heat shape the heat-rejection side as much as the hall.
3. Who runs it at 3 a.m.? A system your team can't maintain is a risk, however efficient it is on paper.
4. How much power do you have? Efficient cooling means more of the connection goes to IT. Survey averages of 1.54 globally and 1.68 in the Middle East and Africa (Uptime) suggest room to improve. Compare options on total facility power, not PUE alone: liquid cooling removes most of the fans inside the IT equipment, which moves load across the PUE boundary and can flatter the number.
5. Can you change your mind later? Pipework routes, floor strength and plant space left in phase one decide whether a hall can move from air to liquid without a shutdown.

Where people go wrong

One mistake is choosing liquid because it's the trend, then finding the plant, water treatment or team isn't ready. The other is staying on air and running out of headroom sooner than planned. Write down the density plan first. The cooling choice usually follows.

We're brand-neutral, so we compare these options on your site, not from a catalogue.