Kansas regulators have granted Westar Energy a $50 million rate increase that will add an average of $3.54 a month to residential customers’ bills.

Topeka-based Westar is the state’s biggest electric utility. The increase was contained in a multi-party agreement approved Wednesday by the Kansas Corporation Commission.

The agreement allows Westar shareholders to earn a 10 percent profit on their investments. Westar says the extra revenue will also help it maintain customer services, including tree pruning.

Westar originally sought a rate increase of $91 million, while the Corporation Commission staff recommended a hike of $33 million.