A 2012 photo of Pepco employee James Tarantella. (Matt McClain/FOR THE WASHINGTON POST)

Want to keep your energy bills down this summer, or you’re not sure what to do when the power goes out? Michael Sullivan, Pepco’s senior vice president of operations and engineering, offered his advice in a recent online Q&A. Here are five of his tips.

1. Keep your thermostat set to 78 degrees in the summer.

“Health permitting, it is most efficient to keep your temperature set at 78 degrees. That’s also the temperature recommended by Energy Star.”

2. Avoid extreme changes in your thermostat temperature.

“It is inefficient to move your thermostat more than a five-degree differential at a time.”

3. Prevent power outages by pruning your trees.

“When you think about it, the canopy on a tree that has not been pruned can act like a sail on a ship, providing great stress on trees of all sizes. Proper pruning will help allow wind to easily pass through them.”

4. Try an Energy Star audit if your home is old or the temperature varies from floor to floor.

“We recommend an Energy Star assessment where we would make sure your first floor and basement are properly sealed, including crawl spaces, that could result in cooler air leaking out of your home.”

5. Try an attic fan — but not with an HVAC system.

“They can be very useful in improving comfort if the humidity is low. Make sure you’re not using your attic fan against your HVAC system. Attic fans work on the premise that you pull cool air through the windows and release hot air through the roof.”

More from The Washington Post:

Make summer the season for savings

Energy-saving tips

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— Margaret Ely