Quick question - demand window intervals

Simple question - do most utilities use 15-minute or 30-minute intervals for demand billing? Have a customer asking and I've seen both.

Karen, 15-minute is becoming standard but varies by utility and customer size. Most large commercial/industrial accounts are 15-minute. Smaller accounts sometimes 30-minute or even hourly.

Phil's right. Also depends on meter type. Newer digital meters default to 15-minute intervals. Older mechanical demand meters were typically 30-minute.

Check the tariff or call utility metering dept. Interval length should be specified in rate schedule. Makes difference in peak calculations - 15-minute intervals usually result in higher demand readings than 30-minute.

Thanks everyone. Customer has 15-minute intervals on their ComEd account. Explains why demand charges seem high compared to their old utility.