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
Ever notice the lights dim, then return to normal when you turn on a large appliance?
That’s because a large chunk of electricity being delivered to your house is being used to start the appliance. The same thing happens with your AC. It takes a lot of power to get started, and significantly less after it is already running.
Another reason to run constantly is the wear and tear on bearings. While a unit is running, motor shafts are actually rotating on a layer of oil. Every time it turns off, that shaft is resting on the bearing, and starting it causes them to rub together creating wear until the oil separates the shaft from the bearing.
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