How to Calculate a Load Factor

Power companies use load factor calculations to determine how much power is needed for set blocks of time.

Load factor is a term used by power companies to express how much electricity was used over a set period of time compared with how much power could have been used at peak demand. Load factor is an important calculation for power companies as they must be able to satisfy the peak demand needs of all customers. Typically, load factor is calculated for one month blocks of time. Fortunately, the formula for calculating load factor only requires simple division and multiplication.

Things You'll Need

• Calculator

Instructions

1. Choose a period of time for which the load factor will be calculated. While any period of time can be used, months, quarters and years are the most common periods of time used when calculating a load factor.

2. Calculate the maximum demand by multiplying the peak demand in kilowatt-hours by the number of days and hours in the period. For example, if the peak demand is 100 kilowatt-hours and the period is 30 days, multiply 100 by 30 and then by 24.

3. Divide the total number of kilowatt-hours used in the period by the figure obtained for maximum demand for the period. For example, if 36,000 kilowatt-hours were used during the month, divide 36,000 by 72,000. The number obtained after dividing the two figures is the load factor percentage in decimal form.

Tips & Warnings

• Once you have the basic formula, you can then calculate the useable rentable square footage, as long as you have the rentable and load factors, or you can calculate the rentable as long as you have the useable and the load factor.

• When the load factor is excessively high, for example, 20 percent or greater, be sure to bring it to the attention of your client, or whoever is interested in the space. A high load factor basically means that you're getting a lot of non-useable space.

References

• Austin Energy: Understanding Load Factor
• Good Energy: Load Factor, Load Profile and Power Factor
• California Energy Commission: Electrical Load Management