Electric bills on Oahu have jumped nearly 7 percent since May due to rising fuel prices.

In July, Hawaiian Electric Co. customers on Oahu saw their electric bills grow at least $4 for the second month in a row as rising fuel costs begin to boost bills.

“Although electric bills are still lower than in previous years, costs for our customers are going up due to rising fuel prices,” HECO spokesman Darren Pai said last week.

The bill for a typical household using 500 kilowatt-hours on Oahu is $133.43 this month, $4.09 higher than what customers paid in June. The price per kilowatt-hour on Oahu was 24.7 cents, up from 23.8 cents in June.

The typical household using 500 kilowatt-hours on Oahu had a June bill of $129.34, which was was $4.49 higher than what customers paid in May.

Over the past two months, the typical bill on Oahu is up $8.58.

The price of benchmark West Texas Intermediate crude oil went from below $30 a barrel in January to above $50 a barrel in June.

Pai said the electric utility is encouraging customers to be more energy efficient to help stabilize bills.

“As we continue our transition to 100 percent renewable energy, we encourage our customers to use energy wisely to control their electric bills,” Pai said.

Brian Kealoha, executive director of Hawaii Energy, a ratepayer-funded, energy-efficiency program, said energy efficiency is one way Hawaii ratepayers can save money as well as help the state get closer to its goal to achieve 100 percent renewable-energy dependence by 2045.

Kealoha said customers can almost halve their energy bills if they use energy-efficiency measures such as taking shorter showers, changing light bulbs to light-emitting diode (LED) or compact fluorescent (CFL), using a Smart Power strip, using plug-in timers and replacing old shower heads with low-flow shower heads.

“If you reduce your length of shower by 2 minutes every day, you can save $30 on your electric bill a year,” Kealoha said. “Combined with low-flow shower heads, that is $60.”

Hawaii Energy said a customer using 832 kilowatt-hours a month — a typical usage without any energy-efficiency measures — results in a bill of roughly $217.96. An energy-efficient customer using 496 kilowatt- hours results in roughly a $132.41 monthly bill.

HECO provides tips on energy saving at hawaiianelectric.com/save-energy-and-money.

Hawaii has the highest electricity rates in the nation, due in part to the state’s use of imported oil for most of its power. Hawaii’s price of electricity is more than double the national average, according to the latest figures from the U.S. Energy Informa- tion Administration.

In 2015 oil made up roughly 71.1 percent of the energy mix of HECO. Oil made up roughly 62.5 percent of the energy mix at Hawaiian Electric Light Co. on the Big Island and 73 percent of the energy mix at Maui Electric Co. HECO imports oil mainly from Southeast Asia and the Middle East. Other states use energy resources such as natural gas, hydroelectric power, coal or nuclear power.

Oahu’s neighbor islands also saw an uptick in their electric bills this month.

The residential rate for HELCO customers on Hawaii island was 28.4 cents a kilowatt-hour, up from June. The average bill this month for a household using 500 kilowatt-hours on the Big Island is $153.85, up from $146.74.

Maui customers paid 27.7 cents per kilowatt-hour, up from 26.7 cents in June. The average bill for a household using 500 kilowatt- hours is $148.08, up from $143.47 last month.

The Kauai Island Utility Cooperative increased its rate to 32.1 cents a kilowatt-hour in July, up from 31.9 cents a kilowatt-hour in June. The average bill for a household using 500 kilowatt-hours of electricity, including a $10.58 customer base charge, is $171.13, up from $170.08.

Maui Electric Co. customers on Molokai using 400 kilowatt-hours of electricity are paying an average of $122.03 with effective rates of 28.1 cents a kilowatt-hour, up from June, when the typical bill was $118.95. On Lanai, those using 400 kilo- watt- hours of electricity are paying 32.5 cents a kilowatt-hour. Lanai residents are paying $139.64 in July compared with $136.22 in June.

The typical customer bill on Lanai and Molokai is measured with electrical use at 400 kilowatt-hours due to lower energy use, HECO said.

Monthly bills include the cost for kilowatt-hours used plus other charges.