Important! Rocky Mountain Power’s wattsmart Starter Kit will no longer be available effective August 5, 2016. For questions or additional clarification, please email HES@rockymountainpower.net.

Energy Factor (EF)

Energy Factor, or EF, is the energy performance metric used for electric water heaters. The higher the EF, the more efficient the electric water heater. To look up your electric water heater’s EF, visit the ENERGY STAR® website.

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