The Public Utilities Commission signed off the company's plan Tuesday, saying the vast majority of those costs were prudent.
During 2011, Idaho Power reported 179,424 megawatt-hours of energy savings, enough to power more than 12,900 average homes for a year.
The PUC's decision will not impact future customer rates. But it's a sign the commission approves of the costs Idaho Power paid for operating 20 programs that were covered for by a 4 percent rider on bills.
Efficiency steps promoted by Idaho Power included financial incentives for customers investing in efficient lighting and encouraging customers to shift power use to periods of lower demand.