Topeka ? The Kansas Corporation Commission on Thursday approved a $43.6 million increase in Westar Energy electric rates.

For households using 900 kilowatt hours per month, the increase will mean an additional $2.59 on monthly bills, while households using 1,500 kilowatt hours will see a $4.32 increase per month.

The new rates take effect April 1.

Under state law, electric utilities can seek annual rate increases for the increased cost of transmission services.

The new rates can be refunded later if officials find errors in the way they were calculated.

But that was unlikely to happen, said David Springe, consumer counsel for the Citizens’ Utility Ratepayer Board, which represents residential and small business customers in rate cases.

“The calculations are usually pretty clean, so I don’t think we’ll find anything in the filing to reduce the total in a meaningful way,” Springe said. “The Legislature didn’t give the commission or CURB much room to argue with these increases,” he said.

Westar is the largest electric utility in the state serving nearly 700,000 customers in much of east and east-central Kansas.