What a hard start kit actually does
A hard start kit gives the compressor an extra jolt of torque at the moment it starts, which can help a struggling compressor get moving. It's a legitimate part with a real use — but only on a compressor that's actually struggling to start, not as a blanket upgrade or a "just in case" add-on.
The one number that decides it: LRA
Locked Rotor Amps (LRA)
Every compressor has a nameplate on the unit listing its LRA rating — the amps it draws in the split second it starts, before the motor gets up to speed. A healthy compressor draws close to that for a moment, then drops to its running amps within about a second. A hard start kit is only justified if the measured startup draw stays near LRA instead of dropping, or the compressor trips on startup. If it starts clean, the compressor is starting within its rated limits, and a hard start kit isn't solving a real problem.
What your technician should show you
Before you agree to a hard start kit, ask for two things:
- The LRA rating printed on your unit's nameplate — they should be able to show you exactly where it is and what it says.
- Proof the compressor is struggling — ideally a video of the amp clamp reading during an actual startup, showing the draw staying near the LRA rating instead of dropping.
If a technician can't show you both of those, there's no justification for the part yet — and it shouldn't be installed. If it starts clean, don't install it.
Why the measurement matters
A hard start kit is a legitimate part — but it's only justified by a measured number, not a feeling. An aging compressor's startup draw can creep up over time, which is exactly why the startup should be measured, not assumed, on every visit where it comes up. We show you the reading before anything is installed.
Waiting on a diagnosis or a part during a hot stretch? We rent portable A/C units in Salt Lake City, delivered and set up, usually same-day.
We'll show you the numbers, not just tell you
If a hard start kit is genuinely needed, we'll show you the LRA rating and the measured startup amps side by side.