Western Massachusetts customers of electric utility Eversource could see their bills shrink this summer.

The utility on Monday sought a 26 percent cut in its basic service customers' supply rate that if approved by state regulators could save the typical homeowner who uses 600 kilowatt-hours of energy per month more than $16 on their bill.

The savings would be offset partially by a $5.74 increase in the rate used to fund statewide energy efficiency programs.

When the changes are combined, monthly residential bills for 600 kilowatt-hours of electricity will decrease to $112.20 from $122.77.

If approved by the Department of Public Utilities, the rate change would take effect July 1.