# How much chiller energy does raising the chilled water temperature by 1 degree save?

Canonical: https://senseible.earth/answers/chilled-water-temperature-raise-energy-saving

About 3% of chiller compressor power for each 1 degree C you raise the evaporator temperature, according to BEE's guide book on electrical utilities. Raising chilled water supply from 7 to 9 degrees C on a busy process chiller can cut its electricity by around 6%, provided the process still gets the cooling it needs.

## Why a warmer setpoint saves power

A chiller's compressor works to lift heat from the evaporator pressure up to the condenser pressure. A warmer chilled water setpoint raises the evaporator temperature and pressure, so the lift is smaller and the compressor does less work for the same cooling. The 3% per degree figure is a rule of thumb for vapour compression chillers; your machine's part-load data sheet gives a closer number.

## How far you can raise it

- Check the coldest user first: a jacketed reactor, a mould, a cold room or an air handler that must remove moisture.
- Air handlers that dehumidify need cold enough water to bring coil temperature below the dew point; raising the setpoint too far raises room humidity.
- Watch pump energy: warmer water carries less cooling per litre at the same temperature difference, so flow may rise and pumps work harder.
- Raise in steps of 0.5 to 1 degree, and log product quality and room conditions for a week at each step.

## Turning the saving into kWh and CO2

1. Find the chiller's annual kWh: from a submeter, or kW per TR times TR times running hours.
2. Multiply by 3% per degree raised to get kWh saved.
3. Multiply kWh saved by the grid factor, 0.710 kg CO2 per kWh, for location-based Scope 2.
4. Compare the next year's chiller kWh at similar load and weather to confirm the saving.

## Common mistakes

Applying 3% to the whole plant's electricity instead of the chiller alone; counting the saving at full load when the chiller runs mostly at part load; and raising the setpoint while users open their valves fully to compensate, which wipes out the gain.

## Worked example: a 200 TR process chiller

- Running: 200 TR x 0.8 kW per TR = 160 kW, for 6,000 hours a year
- Annual use: 160 x 6,000 = 960,000 kWh
- Setpoint raised by 2 degrees C: about 3% x 2 = 6% saved
- kWh saved: 960,000 x 0.06 = 57,600 kWh
- CO2 saved: 57,600 x 0.710 = 40,896 kg, about 40.9 t CO2 a year

The 3% per degree is BEE's rule of thumb; confirm with before and after submeter readings.

## What Senseible does here

Senseible reads kWh from your electricity bills and converts kWh to CO2 at the CEA factor of 0.710 kg CO2 per kWh, so a lower chiller load shows up in your monthly Scope 2 records.

- [Chiller efficiency in kW per TR](https://senseible.earth/answers/chiller-efficiency-kw-per-tr)
- [AC setpoint at 24 degrees savings](https://senseible.earth/answers/ac-temperature-setpoint-24-savings)
- [Chiller plant emissions per TR hour](https://senseible.earth/answers/chiller-plant-emissions-per-tr-hour)

Sources: [BEE Guide Book 3, Energy Efficiency in Electrical Utilities, Chapter 4 Refrigeration and Air Conditioning (beeindia.gov.in)](https://beeindia.gov.in), [CEA CO2 Baseline Database, version 21.0](https://cea.nic.in/cdm-co2-baseline-database/?lang=en)

Last reviewed 2026-10-18.