Residential electric rates on Oahu eased slightly in September from the record high reached last month.

The bill for an Oahu household using 600 kilowatt hours of electricity a month fell to $204.84 in September from $205.44 in August, Hawaiian Electric Co. said. The September rate of 32.7 cents a kilowatt hour is down from a record 32.8 cents a kilowatt hour last month.

The increase in August was in large part due to an interim rate hike that added $3.31 a month to the typical bill on Oahu. High oil prices also have contributed to higher electric rates in recent months, HECO said. Fuel costs account for 61 percent of an electric bill on Oahu.

Residential rates also fell in September on the neighbor islands.

Maui Electric Co. customers saw rates fall to 36 cents per kilowatt hour from August’s 36.6 cents per kilowatt hour. The typical Maui bill fell to $223.40 from $227.36.

Hawaii island residential rates fell to 41.6 cents per kilowatt hour from last month’s 41.7 cents per kilowatt hour. The typical bill fell by 36 cents to $261.37.

On Kauai the rate fell to 41.65 cents per kilowatt hour. Last month the rate charged by the Kauai Island Utility Cooperative was 41.70 cents per kilowatt hour.