When the 2025 corporate average fuel economy (CAFE) and greenhouse gas standards were finalized, the Environmental Protection Agency (EPA) and the National Highway Traffic Safety Administration (NHTSA) supported the standards with thorough technical analyses of technologies available then or expected to be available in the near term. Except for specific credits for some thermal management technologies whose benefits do not manifest themselves on regulatory test cycles, thermal management technologies, those related to controlling heat to and from the powertrain and the passenger cabin, were not widely explored in the analyses.
Since the rule’s finalization, the selection of technologies available to heat or cool a vehicle has ballooned. The list of thermal control technologies includes insulated oil pans, differentials, and transmissions, active grille shutters, electric water pumps, split engine cooling, and many more. Some of these new or improved technologies will exhibit benefits on the test cycles, but many others will realize most of their benefits off-cycle. Furthermore, the overall effect on fuel efficiency depends on the specific baseline and level of electrification. It is estimated that up to 7.5% reduction in CO2 and fuel consumption is possible.
Due to the wide variety and applicability of thermal management technologies, manufacturers have many low-cost options when designing improved vehicle packages.
View the full series of working papers and technical briefs on passenger vehicle technology trends in the U.S. here.