Hotter Than a Hot Tub: The 45°C Breakthrough to Cool AI's Biggest Machines

NVIDIA's latest AI servers can run on coolant warmer than a hot tub - and that counterintuitive choice is one of the biggest efficiency leaps in data center history. Hot tubs sit at about 38 to 40 degrees Celsius, warm enough that most people can only soak for about 15 minutes. NVIDIA's newest AI servers can run their cooling liquid even hotter - up to 45 degrees Celsius, or 113 degrees Fahrenheit.

That higher temperature limit is precisely what makes them more energy efficient. The Rubin generation of NVIDIA AI infrastructure is the world's first to achieve 100% liquid cooling - every chip, every networking component, cooled entirely by liquid in a closed loop with no fans anywhere in the system. This liquid cooling methodology is outlined in the NVIDIA DSX AI factory reference design, a guide that outlines best practices to design, build and operate the entire AI factory infrastructure stack.

Although each generation offers significantly more computing power for each watt, full liquid-cooled AI compute infrastructure enables data centers to dramatically reduce cooling energy consumption - making a meaningful difference to overall data center energy use at hyperscale. "The NVIDIA DSX reference design for AI factories has zero water consumption - we have eliminated massive amounts of power usage and pretty much all water usage," said Ali Heydari, director of data center cooling and infrastructure at NVIDIA. "With dry-cooler-based designs, it's a closed-loop system with no evaporative water cooling - outside of maybe 1% of the year when we might need chillers in some climates.

" Historically, cooling alone has accounted for up to 40% of a data center's electricity consumption , making it one of the most significant areas where efficiency improvements can drive down both operational expenses and energy demands. Industry estimates suggest that raising chiller plant temperatures by just one degree can cut cooling energy costs by about 4%. At scale, those savings add up quickly.

A 50-megawatt hyperscale facility can save over $4 million annually in cooling-related energy and water costs by moving to liquid-cooled infrastructure. In favorable climates, NVIDIA's 45-degree liquid-cooling architecture can enable chiller-less operation with dry coolers, reducing facility cooling water consumption from roughly 2. 6 million gallons per megawatt per year for conventional cooling-tower-based systems to near zero - up to a 100% reduction in water use.

The reason: traditional air-cooled data centers depend on large volumes of cooled air to remove heat from IT equipment, often requiring energy-intensive cooling infrastructure during hot weather. With NVIDIA's 45-degree liquid cooling, heat is captured directly at the chip and transported through liquid loops operating at much higher temperatures, allowing outdoor dry coolers to reject heat efficiently for much of the year while significantly reducing mechanical cooling requirements and facility water consumption. The data center ambient temperature is flexible - warm summer air is fine - because nothing in the server depends on cool air.

The liquid does all the work - and the same liquid can be recirculated in a closed loop so no new water is consumed to cool the chips. com/wp-content/uploads/2026/06/LiquidCoolingInfra_montage_v4. mp4 A New Standard for the Industry Because the NVIDIA Rubin platform integrates 100% liquid-cooled infrastructure, every cloud provider and data center operator building for it is making the transition.

Motivair, the advanced cooling division of Schneider Electric, has worked alongside NVIDIA's product roadmap for nearly a decade - and Richard Whitmore, its president and CEO, says the relationship only intensified as power densities crossed the threshold where air cooling was no longer a viable option. "Once the watts per chip crossed a certain level, liquid cooling became mandatory," said Whitmore.