The Antec KÜHLER H2O 620 is a single 120mm radiator unit comprised of components integrated together to create a simple maintenance-free enclosed system. Unlike custom water cooling kits, no assembly is needed and users don’t need to worry about leakages making this ALC unit very practical and trouble free. Unlike the thicker 920 variant, the 620 is more akin to the Corsair H50 and CoolIT Eco with its smaller radiator. It is also clear that Antec are not aiming at raw performance since it only bundles one fan but it’s understandable given they are targeting a lower price bracket.


With everything being pre-assembled and designed to be leak proof, the Antec KÜHLER H2O 620 is a very compact package. All the components are tightly pre-assembled to reduce the risk of damaging the cooler and prevent leakages. The radiator is the largest and heaviest component but due to being installed to the chassis instead of the motherboard, it is more secure that a heavy air cooler. This leaves the CPU block and pump being the only components being installed to the motherboard, thereby not putting a lot of pressure.


The radiator is 27mm thick and features 12 banks of fins separated by bands carrying the coolant throughout the entire radiator to dissipate heat. The fin spacing is very tight at 1.25mm and the width of each individual fin is 8.5mm. The fins have a corrugated pattern to maximum surface area as is typical with all water cooling radiators. Antec’s packaging ensured that the fins remained undamaged to retain a cleaner look.


To make sure that users don’t accidentally knock the fins and bend them out of shape, there is a gap left between the fins the four fan mounting holes. It also reduces the likelihood of puncturing the narrow linear bands through which the liquid flows through across the radiator. Another benefit is that the fan doesn’t sit as close to the fins and thereby generate a higher pitched noise. This shroud also allows two fans to be installed even if one fan and 4 screws are provided in the bundle.


Like the KÜHLER H2O 920 and other ALC units, the reservoir is integrated to the radiator. The two compartments are each connected to separate tubing so the liquid flows into one and out of the other once it flows through the entire radiator. The tubes are connected to barbs and tightly secured so users can’t pull them off and to prevent leakages. These barbs are designed to withstand high pressures and temperatures although they are not comparable to those used in custom water cooling loops. The fluid used in the system is de-ionised water with a propylene-glycol additive to prevent corrosion of the components.


The tubes are 33cm in length and have a rubberised feel. They are fairly tough but at the same time designed to be flexible. This is achieved by using a non-corrugated design as found on previous Asetek designs. In practise, the tube was quite flexible but the length made it restrictive went trying to install the block and bending the tube into shape. Thankfully the length of the tubing is perfectly distanced such that the radiator can be installed to the exhaust of a chassis.