Calculate annual kWh per square foot, annualize a utility-bill period, set an energy budget, compare a target, and convert kWh/m².
kWh Per Square Foot Formula
The following formula is used to calculate the energy usage per square foot.
Variables:
- E_{sf, annual} is annualized electricity use per gross square foot (kWh/ft²/year)
- E_period is electricity consumed during the entered period (kWh); M is its duration in months
- A is the matching gross floor area in square feet (ft²)
Annualize the period electricity by multiplying by 12 and dividing by its months, then divide by matching gross floor area. This assumes uniform use across the year and does not adjust for season or weather. Target energy budgets and inverse area use the same relationship.
What is kWh Per Square Foot?
Annual kWh per square foot measures electricity intensity, not efficiency or comfort by itself. Compare similar building uses, weather, occupancy and operating hours. This electricity-only measure excludes other fuels and is not total site/source EUI or an ENERGY STAR score. An optional comparable target gives a numerical energy gap, not guaranteed achievable savings.
How to Calculate kWh Per Square Foot?
The following steps outline how to calculate the kWh Per Square Foot.
- First, determine period electricity consumption in kWh or MWh and the number of months covered.
- Next, determine the area (A) in square feet (ft²).
- Next, annualize electricity: annual kWh = period kWh ×12 ÷ months.
- Finally, divide annualized electricity by matching gross floor area for kWh/ft²/year.
- After inserting the variables and calculating the result, check your answer with the calculator above.
Example Problem :
Use the following variables as an example problem to test your knowledge.
Electricity consumption over 12 months =1200 kWh
Gross floor area =1500 ft². Annual electricity intensity =1200 ÷1500 =0.8 kWh/ft²/year.
