Hyper engineering manufacture the “Sure Start”. They OEM to dometic who re-label and brand the unit as the “Smart Start”.
The “soft start” is a new entrant in the market. It may be OEM’d by hyper engineering, but it’s unclear at this time who actually manufacture it, country or origin, development roadmap, sustainability of the company, reliability of the product, etc.. it is my understanding that the developer of the unit is a former MicroAir employee.
All of these units fundamentally work in a similar fashion - inside the box is a capacitor and a hardware board that limits and controls current ramp. The sophistication comes in the logic and software capabilities built into the control board.
None of the above units are as advanced (software wise) as the EasyStart by MicroAir. MicroAir has the ability to learn the characteristics of your particular compressor motor winding to optimize ramp current, and has fault protection for low and high voltage, amongst other features. It doesn’t just ramp the current, it actually protects the AC unit against various fault conditions.
The MicroAir EasyStart is the gold standard and is very well supported from a customer experience perspective.
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