Hard start kits work to protect the heart of your heating and cooling unit, the compressor. The compressor is like the heart of your AC system, pumping out refrigerant at a high enough pressure for it to work its magic and keep us comfortable. Every time the compressor starts, it has to move a large amount of refrigerant through the system. The defect with all lower efficiency AC units is when they turn on the compressor has to work extra hard to start. Imagine riding a bike up a hill, once you are moving, to keep moving isn't too hard but starting from a dead stop takes a lot more effort. That's what's happening every time our air conditioners turn on, they are starting from a dead stop and it wears down the compressors. The hard start kit gives the compressor a friendly push from behind on every start so it doesn't have to work as much, and saves the compressor over time. It allows the compressor to start faster and takes less energy to operate.
Replacing a compressor isn't cheap and can be the most expensive replacement short of replacing your entire system. By taking care of it during its life, you will extend the life of your heating and cooling system and lower your energy bills along the way. A hard start kit with a good run capacitor can reduce the inrush of energy usage by as much as 50%! Keeping the heart of your heating and cooling unit protected also protects the other components as well which leads to less maintenance down the road. The more an AC technician understands about your system the more efficiently it can potentially operate.