When running at low load, electric motors are less efficient. A motor power optimiser (also known as load sensing optimisers) could save between 5 % and 15 % on electricity.

Motor optimisers are solid-state devices that automatically monitor the load on an electric motor. Under low load conditions, they reduce the voltage.

The cost of installing a motor power optimiser depends on its size. A 1.5 kW optimiser, of the type often found in a refrigerated display case, would cost around € 170 to install. If the average running load on the motor were 25 % of full load (i.e. 375 W), it would save 15 % (i.e. around € 45 a year, given electricity prices of around € 0.10 per kWh). Investment costs can be recovered under four years.