Here’s an indication of Rhode Islanders’ worries about rising energy costs:

When National Grid recently sent half of its more than 200,000 residential gas customers a letter about the free energy audit program, they got hundreds of calls in the first week.

Just three weeks ago, there were 129 people on the waiting list to have an energy specialist examine their home for energy efficiency. By July 3, that number had ballooned to 396. “It’s crazy. The phones are ringing off the hook,” said Stephen Hines, the director of residential services for Cranston-based RISE Engineering, which performs the audits for National Grid.

The company had another 140 calls this week from people looking for ways to make their homes more energy-efficient, said National Grid spokesman David Graves –– enough that the utility company is holding off on the energy-audit reminders for the rest of its customers because of the backlog. RISE Engineering performs about 80 audits a week, generally two to three weeks after the requests, he said. Hines said the company is bringing in more resources to handle the demand.

Expect more demand. The state Public Utilities Commission is poised to decide today on National Grid’s request for 21.7-percent increase in electricity rates. And the winter heating season is still to come , a time the energy experts are referring to as “waiting for the other shoe to drop.”

Larry Chretin, the executive director of the nonprofit energy consumer alliance People’s Power & Light, sees more worries over gasoline and oil bills, where a 200-gallon oil tank fill-up this fall is likely to cost more than $800. He hasn’t seen the urgency from electricity customers, yet, but “this could be the tipping point.”

“We think the cost is going to go up. We think the supply of natural gas is very tight and not going to come down unless we reduce the demand,” Chretin said. “We need smart policies, but also need some conservation.”

As the rates go up, energy experts say that people can hold their own electricity costs steady, or even reduce them, by making their homes more energy-efficient.

Start here:

•Shut it off: Turn off lights and appliances when not in use. Stop those energy vampires such as phone chargers, computers, printers and other electronics that suck energy even when off, by plugging them into a power strip that you can shut off all at once.

•Make a change: Replace incandescent bulbs with compact fluorescents, and cut your lighting costs by up to 75 percent.

•Bundle up: Insulate your house, your attic, and your hot water pipes. Insulating your house will keep the cold air out, and covering the pipes keeps water hotter and reduces heat loss.

•Upgrade and replace: Look for the Energy Star label on any new appliances, building materials, and electronics that you’re purchasing. The government-rated label signals when a product meets the energy efficiency guidelines set by the U.S. Department of Energy and the Environmental Protection Agency. Most offer rebates and all are geared to save energy expenses, being 25 to 45 percent more efficient. Upgrade your appliances when you can and check the Energy Star Web site, www.energystar.gov for a list of qualified products.

•Control the temperature: Use a programmable thermostat that keeps the heat low or air conditioning off when you’re away. Set your hot water heater at 120 degrees. Set the refrigerator between 36-38 degrees and the freezer between zero and 5 degrees.

•Air conditioners use a tremendous amount of energy, while fans use considerably less. Use an Energy Star-rated air conditioner (look for the rebate), or cut costs and install ceiling fans to move the air in your house.

•Heating water with electricity? Switch to gas or oil, says Chretin at People’s Power & Light. The long-term savings, especially for families using lots of hot water, will pay off quickly, and there are rebates available for those who switch, he said.

•Heating your house with electricity? Run, don’t walk, to get an energy audit and find ways to save on heating costs, especially if your home isn’t insulated.

•Call for your free energy audit –– you’ve already paid for it in the conservation charge on your National Grid bill. The EnergyWise program (phone: 1-888-633-7947) conducts two-hour visits in homes to look for ways to improve energy efficiency. The program also offers low-interest loans and rebates for improvements. The Weatherization Assistance Program (phone: 574-9100) through the Rhode Island Office of Energy Resources is available to low-income residents.

Since the electricity energy efficiency program was first offered in 1987, National Grid estimated that 886,121 Rhode Island residential and business customers have taken part, saving an estimated total of $660.9 million.

So, use your audit. People in the energy business say they see customers who don’t follow through on recommendations. Start small, say Chretin and Hines. Change your light bulbs and shut off the lights. These simple changes can make a difference.

“If someone followed through on all the things we’ve talked about, I’d be surprised if their bill didn’t drop by a third,” Chretin said.

Tips from People’s Power & Light, RISE Engineering, National Grid and Energy Star.

amilkovi@projo.com