Noticed a huge difference in motor room temps after switching to VRF

We swapped out the old rooftop AC unit for a variable refrigerant flow system on a 12-floor building in Austin last month and the motor room dropped from 95 degrees to a steady 72 in just two weeks. The old unit couldn't keep up with the heat from the controllers and drives in there. Has anyone else seen this kind of improvement or is it just a newer building thing?

3 comments

3 Comments

elliot_patel24d ago

Hold on before you get too excited. That 95 to 72 drop is probably mostly because you swapped out an old, beat-up RTU that was already failing, not because VRF is magic. A properly sized and maintained conventional system could have done the same thing. You might also be seeing a temporary effect from the new equipment running at low load while the building isn't fully heat soaked yet, give it a full summer and see if those numbers stay.

lucasschmidt24d ago

I get what you're saying, but I think you're underselling VRF here. That drop from 95 to 72 isn't just a new vs. old system thing. With a conventional RTU, you'd still see big swings because it can't modulate as well, especially in a building with different zones. Think about a space like a server room that needs constant cooling vs. an office that empties out at 5pm. A standard system just blasts until it hits temp and shuts off, while VRF can run at like 10% capacity and hold steady. @elliot_patel, you're right that a proper design matters, but VRF's inverter technology and variable refrigerant flow let it sip power at part load, which is where most commercial buildings actually live. That 72 isn't a fluke either, it's from not cycling on and off like crazy.

daniel_martin24d agoMost Upvoted

Honestly nobody's even mentioned the humidity control difference.