HVAC hard start kit results


I had a new 4 ton heat pump installed earlier this year. With 100A electric service and many hundreds of feet between my panel and the utility transformer, I could see a momentary flicker in incandescent lights when the compressor started. Also, my standby generator had a voltage/frequency sag when the AC started up, especially if any other large loads were running. To fix this, I added a hard start kit, since the new system didn’t have one from the factory. The power meter screenshots from below tell the story. It should be obvious which one is before and which one is after.

Unfortunately I deleted my HVAC device from Sense last week since it was underreporting usage, so I don’t know whether the kit would have broken detection for that old device. My guess is yes. Hopefully it will re-detect the system quickly.


Cool stuff! I’m wondering if the resolution is too slow to really see…?

I have a 6 ton GSHP and Sense doesn’t show any spike even though it’s not possible. Lights dim and my meter picks up about 10% voltage drop at the mains when set on record.

Refrigerators always show an initial spike for some reason though. I thought I heard ‘normal’ motor starting current is 6-7 times running current.

I think Sense either misses them or ignores them, hell, one of my refrigerators shows 1323w start up in Sense with normal running wattage at 89w. My 6 ton heat pump should be off the charts…


At 1 microsecond sampling, I don’t think Sense misses… But with 1/2 second display resolution (2Hz), in the Power Meter it’s not visible.


Agreed, I know the Sense monitor see’s it, I just think it either don’t display or its so off the charts it disregards it.

Would be nice to know a definite answer so I can have some data to go to the power company with.