ClueLuma

Energy cost index (ECI) calculator

Annual energy expenditure per conditioned area; tariff changes can alter it without changing efficiency.

Units
ECI=Annual energy costConditioned floor area\mathrm{ECI} = \frac{\text{Annual energy cost}}{\text{Conditioned floor area}}

Calculator

Enter the values you know and leave one box empty. Calculate finds the empty one, the result or any input.

$/yr
ft²
$/(ft²·yr)

Worked example

Given

  • Annual energy cost\text{Annual energy cost} = 45,600 $/yr
  • Conditioned floor area\text{Conditioned floor area} = 24,000 ft²
ECI=45,60024,000=1.9\mathrm{ECI} = \frac{45{,}600}{24{,}000} = 1.9

Symbols and units

SymbolMeaningUnit
ECI\mathrm{ECI}energy cost index$/(ft²·yr)
Annual energy cost\text{Annual energy cost}combined energy bills$/yr
Conditioned floor area\text{Conditioned floor area}conditioned areaft²

Related calculators

Results are estimates for study and screening. Check the inputs, units and assumptions before you use them for design, billing or contract decisions.