The 3 Differences Between CRAC and CRAH Units 

Are you building a data centre or computer room? If so, you know that no computer room is complete without a precision cooling system. Heat and humidity are computers’ worst weaknesses, so a cooling system will help protect them and make them last longer. You may come across two types of cooling systems: computer room air conditioners (CRAC) and computer room air handlers (CRAH). But what are the differences between the two? This article breaks those differences down so you can make the best decision for your computer room.

Cooling Mechanisms

On the one hand, the computer room air conditioning uses compressors to cool the room. The computers face the CRAC system, which pumps cool air through perforated tiles onto the computers. It also pushes the hot air into the hot aisle, which is taken and cooled in the refrigerator compression cooling cycle. The CRAC system blows this newly-cooled air onto the computers, repeating the process.

On the other hand, the CRAH system uses a chiller. It sucks in hot air from the room and sends it to the cooling coil filled with chilled water. The air goes around the coil, cooling it with a direct expansion mechanism. The air is sent back out, and fans disperse it to cool the room. The CRAH system requires underlying plumbing to supply it with water.


CRAC precision cooling units have several parts that require regular maintenance for the whole system to work. Thus, you might have to set aside some budget for regular maintenance checks. Meanwhile, CRAH systems require less maintenance because of their fewer parts, but you do have to maintain their plumbing regularly. Otherwise, the cooling won’t be as efficient.


Your computer room’s electrical load affects which system is better for you. A CRAC system is better if it uses less than 200 kW of electrical loads daily. A CRAH system suits your room better if it uses more than that. Additionally, CRAC’s use of refrigerators and compressors makes them less efficient than CRAH’s chillers.

In conclusion, while CRAC units are easier to install, they require more maintenance and are suited for smaller rooms. Meanwhile, CRAH units require less maintenance but need plumbing installation beforehand, but they’re best for larger rooms. Use this information to determine which precision cooling system is best for you.

Are you in need of precision cooling for your computer room? Canatec offers many options for both CRAC and CRAH units, so you can get whichever is best for your needs. Learn more about their high-quality cooling systems by visiting their website