A hard start should have been called an "easy start".
Originally posted by gtownguy
What exactly does a hard start kit do and are they normally part of every heat pump system
It ensures that the compressor will start under a load.
They are always used with reciprocating compressors when the metering device is a thermostatic expansion valve (TEV or TXV, depending on brand name & custom).
Since a TEV is VERY common on heat pumps, the use of a hard start is required.
Some scrolls will start without one.
Your contractor can help you with which models need a hard start.
They are also used when voltage is borderline low, or if equipment is having trouble starting.
A hard start is a good thing.
RSES Certificate Member Specialist
Southwest Regional Association of RSES Secretary, 2017