Initially, the EPA rated the Energi's combined city/highway fuel economy in all-electric mode at 100 miles per gallon gasoline equivalent (MPG-e) (2.4 L gasoline equivalent/100 km). Later, due to complaints from owners not achieving the sticker fuel economy, and following a technical review, the official EPA rating in EV mode was downgraded to 88 MPG-e (). The Fusion Energi combined fuel economy equivalent is the same as the 2013 Ford C-Max Energi. In a similar way, in hybrid operation, initially the Energi had an EPA combined city/highway fuel economy of . It was later downgraded by the EPA to . EPA's rating for combined EV/hybrid operation is 51 MPG-e (4.6 L gasoline equivalent/100 km), which allowed the Fusion Energi to rank at the time in sixth place, together with the C-Max Energi, among the top ten EPA-Rated Fuel Sippers since 1984.
