# Do voltage optimisers or servo stabilisers really cut electricity and emissions?

Canonical: https://senseible.earth/answers/voltage-optimiser-servo-stabiliser-savings

Only for loads that use less power at lower voltage, such as some lighting and resistive heaters. Motors on drives, LED drivers and electronics often save little. A stabiliser also has its own losses. Measure kWh with the unit bypassed and in service before counting any saving.

## Loads that may respond

- Older lighting and resistive heating.
- Lightly loaded motors without drives, sometimes.

## Loads that usually do not

- Motors on variable speed drives.
- LED drivers and electronics with regulated supplies.
- Heaters on thermostats, which simply run longer.

## How to test

Alternate weeks with the unit in service and bypassed at similar production, and compare kWh per unit made. Count only a measured saving, multiplied by 0.710.

## What Senseible does here

Senseible reads fuel invoices and electricity bills and applies IPCC 2006 factors and the CEA grid factor (0.710 kg CO2 per kWh), so you can compare Scope 1 and 2 before and after a change from the documents themselves.

- [Transformer losses](https://senseible.earth/answers/transformer-losses-in-scope-2)
- [LED retrofit savings](https://senseible.earth/answers/led-retrofit-energy-co2-savings)
- [IE2 to IE4 motors](https://senseible.earth/answers/ie2-to-ie4-motor-replacement-savings)

Sources: [CEA CO2 Baseline Database for the Indian Power Sector](https://cea.nic.in/cdm-co2-baseline-database/?lang=en), [Bureau of Energy Efficiency](https://beeindia.gov.in), [GHG Protocol Scope 2 Guidance](https://ghgprotocol.org/scope-2-guidance)

Last reviewed 2026-10-22.