Skip to content
gigabiome
Try Plant Check

Free calculator

Chiller plant energy cost calculator (kW/ton)

A chiller plant's electricity is its load times its efficiency. This calculator turns plant size, equivalent full-load hours and kW/ton into annual kWh and cost, and shows what an efficiency improvement is worth.

Formula
kWh = tons × EFLH × kW/ton
Last reviewed
2026-09-29

Inputs

Example values are pre-filled so you can see the result. Replace them with your plant's.

Results

Example values
Electricity saved per year
100,000 kWh
Share saved
14.3%
Cooling delivered
1,000,000 ton-h
Electricity now
700,000 kWh
Electricity at target
600,000 kWh
Show the math
  1. kWh now = tons × EFLH × kW/ton now= 500 × 2,000 × 0.7 = 700,000 kWh
  2. kWh at target = tons × EFLH × kW/ton target= 500 × 2,000 × 0.6 = 600,000 kWh
  3. Saved = kWh now − kWh at target= 700,000 − 600,000 = 100,000 kWh
  4. Share saved = saved ÷ kWh now= 100,000 ÷ 700,000 ≈ 14.286%

kWh = tons × equivalent full-load hours × kW/ton.

How it's calculated

kWh = tons × equivalent full-load hours × kW/ton. Equivalent full-load hours are the year's ton-hours divided by the plant's design tons; your BMS trend data or utility interval data gives the real figure.

kW/ton here should be measured, not nameplate: chillers run most hours at part load and in warmer condenser water than their rating. For what moves kW/ton, read condenser approach and fouling.

Questions

How do you calculate chiller energy use?

Multiply the cooling delivered (ton-hours) by the plant's efficiency in kW per ton. For a year, ton-hours are design tons times equivalent full-load hours.

What does kW/ton mean?

Kilowatts of electricity per ton of cooling (12,000 BTU per hour). Lower is better. Measure it from chiller power and chilled-water flow and temperatures rather than relying on nameplate ratings.