Arizona utility regulators have approved a rate increase for the state's largest electric company that will boost the average homeowner's bill by about $6 a month starting Saturday.

Tuesday's 4-1 vote by the Arizona Corporation Commission comes months after Arizona Public Service reached a deal with solar and consumer advocates over its planned increases. The deal allowed smaller rate increases and cuts to what APS pays rooftop solar customers than the company originally proposed.

The deal allows a 4.5 percent residential rate increase, below the 8 percent the utility proposed last year. An administrative law judge largely agreed with the proposal and the commission also has now signed off.

Commissioner Bob Burns opposed the measure, saying APS doesn't need the increase and hasn't been open about political spending that backed commissioners in recent elections. He's suing the company to try to force it to reveal its political spending.

APS released a statement Tuesday regarding the changes, including a breakdown of what is changing starting this weekend. The statement reads:

The rate adjustment will take effect on Aug. 19. Customers do not need to take any immediate action. APS will communicate with customers starting in the fall about how they can pick a new rate plan. The new rate options include incentives for more efficient use of energy and additional opportunities to save money. Among the benefits of the rate plans:

  • An updated time-of-use plan that will become the standard rate for future customers;
  • Two optional demand rate plans, plus a pilot demand rate for customers with certain types of technology at their homes, all of which would provide even more opportunities to save;
  • Additional savings for customers with two more off-peak hours on weekdays (3 p.m. to 8 p.m. instead of noon to 7 p.m.) and four more off-peak holidays; and
  • A plan that includes a super off-peak period of 10 a.m. to 3 p.m. weekdays in winter to encourage customers to use more electricity at midday when solar production is abundant and demand is low.