The Hot Aisle Containment Guide

Introducing Hot Aisle Containment.

We are sure you may have Googled it a few times or heard the word floating around the meeting room — that’s why you’re here, right?

Hot aisle containment can be achieved through various methods, all with their pros and cons that need to be considered before deciding on which one will work best for you.

Read on to find out what hot aisle containment is, how it works, why it’s important, and answer some frequently asked questions about the topic, so you know exactly what you’re getting yourself into!


In the article:

  • What is Hot Aisle Containment?
  • How does Hot Aisle Containment work?
  • What’s the Point of Enclosing Hot Exhaust Air?
  • Hot Aisle Containment Options
  • Hot Aisle Containment vs Cold Aisle Containment
  • The Bottom Line – Is Hot Aisle Containment Right for your Data Center?
  • Your Hot Aisle Containment FAQ’s Answered

What is Hot Aisle Containment?

Hot aisle containment (HAC) solutions are design measures used in data centers to prevent the “hot spots” of heat generated by servers from adversely affecting other equipment and causing high cooling costs.


How does Hot Aisle Containment work?

As the name suggests, a hot aisle containment system encloses the “hot aisles” of a data center. These pathways start at the exhaust point of server cabinets and collect the hot air they emit.

Then, the containment systems take advantage of the natural properties of hot air rising. The hot aisle containment curtains funnel the warmer air upward to an AC return system such as a drop-ceiling void. The cooling units cool the air and return it to the computer room.


What’s the Point of Enclosing Hot Exhaust Air?

The hot exhaust air emitted from servers can damage equipment by increasing fan speeds. And when hot and cool air are free to mix, your data center won’t achieve the energy savings it needs.

Enclosing hot exhaust air avoids these problems to create a safer, higher-efficiency data center.



Hot Aisle Containment Options

HAC systems feature the same mechanism of a physical barrier enclosing hot aisles and decreasing return air temperature. They also require you to implement a proper fire suppression system.

However, there are several ways you can implement HAC systems. See below for a few of the most common options:

Ducted HAC

  • Can accommodate standalone IT devices on the computer room’s perimeters
  • Ideal for data centers with a raised floor and drop ceiling plenum

Dusted Rack

  • Complete solution for rooms with an overhead plenum
  • Requires fire suppression within the ducts
  • Ductwork and other overhead obstructions may interfere with the duct


Row Cooled HAC

  • Adds ceiling panels or cooling units in between racks
  • Maximizes raised floor cooling
  • Hot aisle containment in-row cooling is ideal if your existing data center has a hot and cold aisle arrangement


Rack Air Containment System

  • Prepackaged solutions available for quick deployment
  • Consumes more raised floor space
  • May not require a fire suppression system


Hot Aisle Containment vs Cold Aisle Containment

HAC is crucial as it keeps the warm air from server racks separated from supply air. In a raised floor system, it will return air at the ideal temperature.

But, you should realize that HAC isn’t the only way to protect equipment and increase energy efficiency. Another option you have at your disposal? Cold aisle containment (CAC).

Cold aisle containment closes the cold pathway doors and presents advantages such as being more cost-effective. It also prevents the rest of the computer room from becoming a hot air return plenum. Your technicians will appreciate the consistent, comfortable temperature of their working environment.

Any type of containment system will offer better temperature control and energy savings than no containment system. However, in most cases, HAC is the more popular option because of its increased energy efficiency. Here’s a closer look at the most significant benefits of this contained aisle design.

Reduces Mixing of Hot and Cold Air

Hot aisle containment panels are more effective at reducing the mixing of supply and bypass air. Your system won’t require as much fan energy, which will lead to lower operating costs and increased efficiency.

Increase Cooling Capacity

When the containment system reduces mixing, units can cool warm air much faster due to the better heat exchange across the AC coil systems. This increased cooling capacity of the space means that your computers won’t suffer the consequences of higher temperatures.

Fewer Special Considerations

CACs often require you to make special considerations for non-rack-mounted equipment. These extra cooling measures can override the affordability of CACs. With an HAC, however, you get more of an all-inclusive package. Most data centers find the higher cost to be well worth the peace of mind they get.

Fewer Cooling Units

While these containment structures require a raised floor and can have more intricate installation processes, HACs only need one redundant cooling unit. Several aisle containments can rely on this one unit, reducing your operating costs.

Greater Resilience

HACs are better equipped for failure scenarios than CACs. They provide more cool air to servers, allowing them to withstand extreme temperatures until you can address the issue.


The Bottom Line – Is Hot Aisle Containment Right for your Data Center?

Hot and cold air regulation is essential for any data center. This guide shows that hot aisle containment is an effective method for keeping your equipment cool while protecting your bottom line.

But because we discussed an alternative, you might wonder whether the hot aisle or the cold aisle containment design is right for your data center.

Most providers recommend that you never mix the two types. Instead, have an expert analyze your aisle doors and existing system and install the appropriate solution. This way, you’ll protect your equipment and enjoy significant savings.


Your Hot Aisle Containment FAQ’s Answered

Have more questions? Here are some FAQs we get from data centers like yourself.

What are Hot Aisles in a Server Room?

Hot aisles use data center curtains or some other method to channel hot air out of the room.

What are Cold Aisles in a Server Room?

Cold aisles have closed doors that funnel supply air directly to server equipment.

What is a CAC in a Data Center?

CAC stands for cold aisle containment. Like an HAC system, a cold aisle containment system improves cooling efficiency and reduces energy consumption. However, it functions differently as it encloses the cold aisle end doors to deliver cold air directly to the servers.