The January 2026 update to En-ROADS included changes to the ranges of the “Energy efficiency of new transport” and “Energy efficiency of new buildings and industry” sliders:
- Minimum value changed from -1.0%/year to 0.0%/year
- Maximum value changed from 5.0%/year to 3.0%/year
The efficiency slider limits were tightened based on a combination of several factors:
1. Prior improvements to the model: In October and November of 2025, improvements were made to the electrification and end-use energy demand sectors of the model that resulted in higher growth of electric carrier adoptions across end uses (transport, buildings, and industry) in the Baseline Scenario and stronger responses to policies that promote electrification and energy efficiency.
2. Changes to the slider function: As a part of the January 2026 release, the way electric-only capital (i.e., buildings and industry equipment that is by definition electric like lighting, electronics, and motors) responds to the efficiency slider was changed. Before, the effect was calculated as a percentage change relative to a baseline (multiplicative). Now it’s calculated as a simple increase or decrease from that baseline (additive).
3. Incorporation of energy efficiency learning: The model now accounts for carrier end use efficiency improvements endogenously through learning.
4. Calibration to the latest data: Many of the En-ROADS calibration data sources were updated recently and the model has been tuned to reflect the latest data.
As a result of these improvements, the original best- and worst-case inputs for efficiency sliders no longer made sense and could result in “double-counting” of efficiency gains. Therefore, the ranges were updated to reflect reasonable high- and low-end possibilities for end use efficiency changes consistent with the latest literature and observed historical data. The resulting changes have limited impact on the average user and workshop facilitator as moving these sliders to the maximum and minimum has approximately the same effect on key climate indicators (e.g., global temperature change, greenhouse gas emissions, etc.) as previously released versions of the simulator.