WASHINGTON, D.C. - Pepco asks all of its customers to conserve energy tonight as high temperatures are forecasted to affect the entire Mid-Atlantic region.

For customers participating in Pepco's Energy Wise Rewards program in Maryland, today will be a Critical Peak Savings Day and a PJM-mandated conservation event has been called from 3 to 9 p.m.

PJM manages the high-voltage electric grid and the wholesale electricity market that serves 13 states and the District of Columbia. This means that Pepco will cycle the participants' air conditioner compressors off for short intervals during these hours. Because the air conditioner fans will continue to run, however, most customers will not notice a temperature change in their home, and those who do should experience only a 1- to 3-degree change. It may take up to a half-hour after the event ends at 9 p.m. for air conditioners to resume normal operations.

Energy Wise Rewards is a voluntary program that offers customers a choice of a programmable thermostat or an outdoor switch, which the utility installs at no charge to the customer. During summer periods of peak electric demand, Energy Wise Rewards works to reduce electricity usage by cycling central air conditioner compressors off for short periods of time during periods of peak electricity use. Maryland and District customers will receive a bill reduction in return for allowing Pepco to cycle their air conditioners a few days each year. Customers can get more information about Energy Wise Rewards at pepco.com/rewards or 1-866-353-5798.

Energy Wise Rewards participants may not override this PJM-mandated conservation event. PJM, the regional transmission organization for the mid-Atlantic region, has determined that energy use must be reduced throughout the region to keep the electricity supply stable and prevent rolling brown outs.

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Demand for electricity is expected to increase as the excessive heat and humidity continue. Pepco asks all customers to conserve electricity. Customers can take simple conservation steps:

• Set air-conditioning thermostats at 78 degrees and use an electric fan, which doesn't require as much energy, and the air will seem cooler without sacrificing comfort.

• Keep window shades, blinds, or drapes closed to block the sunlight during the hottest part of the day and to retain cooler air inside your home or business.

• Limit the use of electrically heated water and turn off non-essential appliances and as many lights as possible.

• Limit opening refrigerator or freezer doors.

• Postpone using high-energy appliances like electric stoves, washing machines, dishwashers and dryers until the evening.

For more information and updates, visit www.pepco.com, follow us on Facebook and Twitter at PepcoConnect and download our mobile app at www.pepco.com/mobileapp .

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Pepco, a subsidiary of Pepco Holdings, Inc. (NYSE: POM), delivers safe, reliable and affordable electric service to more than 788,000 customers in Maryland and the District of Columbia.