Energy Audit Calculator Formula

Understand the math behind the energy audit calculator. Each variable explained with a worked example.

Use the Energy Audit Calculator

Formulas Used

Energy Use Intensity

energy_intensity = kwh_per_sqft

Total Annual Energy Cost

total_cost = total_energy_cost

Potential Savings (20%)

potential_savings = total_energy_cost * 0.20

vs. Benchmark

vs_benchmark = (annual_kwh - benchmark_kwh) / benchmark_kwh * 100

Variables

VariableDescriptionDefault
annual_kwhAnnual Electricity Use(kWh)10800
annual_gas_thermsAnnual Natural Gas(therms)500
sqftBuilding Square Footage(sq ft)2000
elec_rateElectricity Rate(USD/kWh)0.15
kwh_per_sqftDerived value= annual_kwh / sqftcalculated
total_energy_costDerived value= annual_kwh * elec_rate + annual_gas_therms * 1.5calculated
benchmark_kwhDerived value= sqft * 4calculated

How It Works

How to Perform a Basic Energy Audit

An energy audit compares your actual energy use against benchmarks to identify saving opportunities.

Key Metric: Energy Use Intensity (EUI)

EUI = Annual Energy / Square Footage

Residential Benchmarks

  • Efficient home: 3-4 kWh/sq ft/year
  • Average home: 5-6 kWh/sq ft/year
  • Inefficient home: 7+ kWh/sq ft/year

    • Most homes can reduce energy use by 15-30% through basic efficiency improvements.

    Worked Example

    A 2,000 sq ft home using 10,800 kWh electricity and 500 therms gas annually at $0.15/kWh.

    annual_kwh = 10800annual_gas_therms = 500sqft = 2000elec_rate = 0.15
    1. 01Energy intensity: 10,800 / 2,000 = 5.4 kWh/sq ft
    2. 02Electricity cost: 10,800 * $0.15 = $1,620
    3. 03Gas cost: 500 * $1.50 = $750
    4. 04Total cost: $1,620 + $750 = $2,370
    5. 05Potential 20% savings: $2,370 * 0.20 = $474/year

    Ready to run the numbers?

    Open Energy Audit Calculator