The definition of overkill: Cooling an RTX 4090 to a claimed 20°C with a household air conditioning unit

I’ve seen some wild and wacky PC cooling solutions in my time, but this one might beat them all: An RTX 4090 cooled with a household air conditioner.

Chinese techtuber 电解碳酸钠 (which machine translates to “Electrolytic sodium carbonate”) has shown off the extreme cooling system in a video on Bilibili.

The channel says that it’s still waiting on a water block for a planned RTX 5090 build, but in the meantime the air conditioner has been hooked up to an RTX 4090, dropping temps down to a claimed 20 degrees Celsius under load (via Tom’s Hardware).

Given the power (and size) of the air conditioning unit used here, that’s probably no surprise. It’s rated to 12,000 BTU of cooling, with a 1.2 kW power draw. That means it’s not exactly the most efficient of cooling solutions, although it is mounted on castor wheels for, err, ease of use.

And it’s even been festooned with a faceplate featuring the logos of some popular PC hardware brands. I don’t think I’ve ever seen Nvidia, AMD, and Intel logos featured quite so prominently on a build—but when you’ve got this much chassis real estate to play with, why not.

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An air conditioner standing next to a gaming PC with Nvidia, AMD and Intel logos visible. — (Image credit: 电解碳酸钠 on Bilibili)

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The internals of a liquid cooled PC using a household air conditioning unit. — (Image credit: 电解碳酸钠 on Bilibili)

The processor on the test system is Intel’s Core i9 13900K, which also appears to be cooled by the outer air con unit. Well, it does run a little hot, after all.

Two hoses are diverted from the outside of the air conditioner into the rear of the PC and then into what looks like respective water blocks, and, aside from the bulk of the air conditioner itself, it seems like a surprisingly neat and tidy job.

Plus, you can even feel the breeze as your PC plunges to extremely low temperatures, as our host demonstrates by sticking her head in front of the main fan:

A person putting their head in front of an air conditioning fan attached to a gaming PC. — (Image credit: 电解碳酸钠 on Bilibili)

Well, it’s all in good fun, isn’t it? The host later says that the setup seems ready for the addition of a 14900K and RTX 5090, and possibly even a future RTX 6090, too.

Given that we’ve been impressed with the performance of the RTX 5090 FE cooler (and by how slim and svelte it looks despite the mighty power of the chip inside), all of this seems very unnecessary. However, if ultimate cooling is the goal, it’s difficult to think of a system that would provide more headroom than this.

Should it take the top spot as an addition to our best CPU coolers guide, perhaps? Err, no. A 12,000 BTU air conditioning unit is a very expensive and impractical thing, at least for these purposes. Still, hats off for the attempt, at the very least.