Noctua’s pumpless ‘thermosiphon’ liquid cooling unit is expected to be released in 2026 and has already given me a free lesson in basic thermodynamics

Noctua is perhaps best known for its brown fans and conventional air coolers, but it might not be long until it makes its move into the liquid cooling world, too. Noctua founder, Roland Mossig, showed off the prototype of its pumpless thermosiphon cooling unit in Japan this weekend, and according to Japanese tech outlet Hermitage Akihabara it’s expected to be released in 2026.

Our Jacob first took a look at the thermosiphon prototype at Computex last year, and came away impressed. Essentially it creates a vapour chamber-like effect by using heat emitted from the CPU to evaporate a refrigerant, which then moves up a vapour tube into a fan-cooled condenser, where it cools off, condenses back to a liquid state, and makes its way back to the CPU to be heated again—no pump required.

“When we release it, it will be a product that delivers performance that will satisfy our customers” said Mossig. Hermitage Akihabara reports that “if things go smoothly, the product is expected to be commercialized sometime in 2026.”

It is worth noting, however, that we have used multiple machine translations on this article—the standard Google Translate suggested Mossig said: “If we release it….” while the latest Gemini AI translation gave us: “When we release it…” Given the way it’s phrased after the initial statement, the “When” makes more sense.

Noctua says that, thanks to the cooling headroom created by absorbing heat in the liquid before vaporisation occurs, it can potentially deliver AIO level performance without many of the downsides of a traditional liquid cooling system, like pump noise, vibration, or risk of mechanical failure.

There is one potential drawback, however, and that’s the position of the radiator. It needs to be mounted above the CPU to create the vapour/fluid exchange effect, unlike a conventional AIO system which can be mounted vertically in the front of a PC case as long as the top of the radiator is above the height of the pump.

Still, many modern PC cases are built with top venting that should be suitable, and the radiator/condenser unit itself looks to be a 280 mm unit which should fit in even some small form factor machines.

The other factors, of course, are performance and price. If Noctua really has managed to achieve AIO-like cooling performance without a pump then it strikes as an attractive, potentially more reliable cooling solution for those of us that view watercooling pumps with suspicion, although pricing remains a question mark.

I’d imagine the R&D costs here are quite significant, and Noctua is not known for making low-priced products compared to some of its competitors. Still, if it does end up being priced competitively with conventional liquid cooler offerings, it might have a winner on its hands. Plus, we’ve all learned a thing or two about thermodynamics and refrigerants. And who could possibly put a price on that?