Home a/c systems – Why is it more efficient for it to run continuously a couple of hours rather than cycling on/off so often?

Question

For the sake of argument and discussion, let’s use a perfectly matched, balanced, and calibrated R-410a home a/c system as an example.

Why do folks say it’s more efficient for said home a/c system to run continuously for 2 hours and then off for 5 minutes instead of cycling on/off much more often to achieve the same interior cooling setting on the thermostat? (I understand how home a/c system work, but I’d like to know why some say longer run times = greater efficiency.)

I’ve heard this claim time and again, but I’d like to know the science behind it. I live in Texas where a/c units run for hours during the day from June through September.

In: Engineering

Answer 1

Imagine your AC is that one friend who hates getting out of bed. Once they’re up and moving, they’re fine. But if you keep waking them up every 5 minutes, they’ll be grumpy and inefficient all day!