The Setup: A Project Moving Too Fast
Back in March 2023, I was handed a rush order for a new control cabinet installation. The client needed it live in six weeks. Budget was tight—tight enough that my boss looked at me and said, 'Find savings wherever you can.'
I was the project engineer, responsible for specifying enclosures, cooling, and power distribution. I'd been doing this for about five years at that point. Thought I had a handle on things.
I was wrong.
The Mistake I Almost Made
The cabinet we selected was a standard Rittal TS 8 enclosure—solid choice, easy to work with. But when it came to cooling, I went cheap. Instead of the proper Rittal fans or a Blue e+ cooling unit, I opted for a basic filter fan combination. Saved maybe $200 upfront.
Here's the thing: that decision almost cost us the entire project.
The First Warning Signs
Two weeks after installation, I got a call from the site supervisor. 'Temps are high,' he said. 'Like, uncomfortably high.' I pulled the data logs: internal temperature was hitting 110°F regularly. The specs called for a max of 95°F.
I figured maybe the ambient temp was off. Checked the room: 78°F. So the filter fans were pulling in relatively cool air, but not moving enough volume to keep the cabinet safe. Worse, dust was building up on the filters after only a week.
The Turning Point: A Near-Disaster
The moment I'll never forget was a Thursday afternoon in April. I got an alert: one of the PLCs inside the cabinet had hit thermal shutdown. That module controlled a critical production line. One hour of downtime = roughly $3,000 lost.
We patched in a temporary fan—not ideal, but workable—and I immediately started looking for a real solution. I called our Rittal enclosure distributor (shoutout to the rep who didn't laugh at my panic) and asked for a proper cooling unit.
"The rep asked me one question: 'Did you size the cooling correctly?' I didn't have a good answer. That's when I learned the hard way."
The Fix: Rittal Blue e+ to the Rescue
We swapped in a Rittal Blue e+ cooling unit—specifically the 7800 series for that cabinet. Installation took about 2 hours. The difference was immediate: cabinet temp dropped to 88°F and stayed there. Energy consumption? The Blue e+ units use about 55% less energy than traditional cooling (thankfully, that's a documented feature, not guesswork).
The Cost of Getting It Wrong
Let's break down the financials (because my boss sure did):
- Initial filter fan setup: $150
- Emergency service call + temp fan: $400
- Lost production time: $3,000 (for that one shutdown)
- Replacement Blue e+ cooling unit: $850
- Total cost of my 'savings': roughly $4,400
If I'd spec'd the proper cooling from the start? About $850, no emergency, no downtime. That's a lesson in total cost of ownership (i.e., not just the purchase price).
What I Learned (and Now Preach)
The most frustrating part of this experience: I knew better. I'd even written internal guidelines about cooling sizing. But when time and budget pressure hit, I reverted to shortcuts.
Three things I now check before any cabinet spec:
- Actual heat load — measure or estimate realistically, not optimistically
- Ambient conditions — filter fans work fine in clean, temp-controlled rooms. Dusty factory floors? Not so much.
- Future expansion — that cabinet eventually got two more modules. Our original cooling plan would have failed again.
To be fair, filter fans have their place. For some light-duty applications, they're perfectly adequate. But if you're running PLCs, drives, or any heat-generating gear in a industrial environment, don't cheap out on cooling.
The Closing Thought
I didn't fully understand the value of proper enclosure cooling until that April afternoon. Now, I maintain our team's pre-installation checklist—and 'cooling size verification' is the first line.
If you're reading this and thinking about saving a few hundred bucks on your next Rittal enclosure project: don't. The hidden costs will find you. And they're much higher than the upfront price.
