SureStart® - single phase

Comparison of hard start and soft start technology for single phase HVAC compressors

Electronic soft starter is a sophisticated and intelligent device designed to reduce the starting current of the compressor by actively controlling the current in both the run and start windings.

They actively (phase control) limit the current through run winding while a balanced value of start capacitor is connected in situ to provide the optimal torque required to start a compressor any operating voltage.

Along with soft starting, electronic soft starters also provide a substantial number of built-in features to pre-emptively protect the compressor under abnormal circumstances.


Compressor health is often the single biggest concern in any HVAC application as replacing faulty
compressors can be quite labour intensive and expensive.

Considering the abundance of protection as compared to any start assist techniques, electronic soft
starters are an economical and valuable proposition for compressor starting and protection.

To read more about the comparison, download the sheet at the bottom of the page.

Start current redcution

Start current reduction

Hard starters actually increase the start-up current giving the compressors a harder and louder kick at each start, while our SureStart® soft starter significantly reduces the start-up current making a softer and quieter.

A hard start will shorten the life of your HVAC unit and can cause pre-mature failure to the compressor. While a SureStart® soft starter will extend the life of the compressor improving the longevity of your HVAC unit.

Supply voltage dip

Supply voltage dip


In off-grid generator or inverter based HVAC applications, HVAC compressors struggle to start.
This is due to their limited source capacity which is often aggravated by voltage drop across long cable overlays.
Hard start kits are of no benefit in such cases.

Surestart soft starters are well suited to reduce start-up kW demand and also offer active cable impedance
compensation for reliable compressor starts.

Do you have any further questions?
Contact us.



Key Features

Key Features 1