A comparative analysis of design-stage energy calculations and post-occupancy measured performance, using publicly available data from the ZEB Demonstration Project by the Sustainable open Innovation Initiative (SII)
Last Updated: April 4, 2026
Multi-faceted analysis of design primary energy reduction rates vs. actual performance across all 194 buildings.
Filter by building use type. Points above the 45° line indicate actual performance exceeded design estimates.
Filter by climate zone (1=coldest to 8=warmest) to analyze climate-related trends.
Distribution of "Actual Reduction − Design Reduction". Positive values indicate actual exceeded design.
Reduction by design ZEB rank (excl. on-site gen.)
Design vs. actual by climate zone
Comparison by building size
Overall reduction by construction type
Design vs. actual energy reduction by building use (showing uses with 3+ buildings).
Number of transitions from design to actual ZEB rank.
| Design Rank | Actual Rank | Count | Share | Change |
|---|
Detailed analysis of energy efficiency performance (BEI) for HVAC, ventilation, lighting, hot water, elevators, and miscellaneous equipment.
BEI values visualized as scatter plots. Points below the 45° line indicate actual BEI outperformed design.
BEI = 1.0 is the baseline; lower values indicate higher efficiency. Toggle between mean and median.
Side-by-side comparison of average primary energy consumption per category.
Comparison of non-BEI energy consumption (office equipment, cooking, etc.) by building use.
Comparing design and actual BEI by equipment category for new construction (117) vs. existing/renovated (77) buildings.
Comparison of design vs. actual performance for solar PV and cogeneration systems.
Comparing design generation estimates vs. actual output for 118 buildings with solar PV. Toggle outlier visibility.
Energy savings by building use for 20 buildings with cogeneration systems.
This analysis is based on data from 194 buildings in the ZEB Demonstration Project. Primary energy consumption is calculated from baseline values per energy conservation standards (PAL*/H25), design values via WEBPRO, and operational measurement data. Reduction rates are on an "excluding on-site generation" basis. BEI is the ratio of primary energy consumption per equipment category to the baseline (values below 1.0 indicate energy savings). Solar PV and cogeneration values are displayed as absolute values. "Miscellaneous" refers to non-BEI energy consumption such as office equipment, cooking, and servers. Construction types are classified as "New" (117 buildings) and "Existing/Renovated" (77 buildings).
This report was independently compiled and analyzed based on data published by the Sustainable open Innovation Initiative (SII) for the ZEB Demonstration Project, and has not been officially created or endorsed by SII. The content is provided for informational purposes only and does not constitute advice regarding specific building projects, equipment design, or investment decisions. While every effort has been made to ensure accuracy, errors may exist in the data processing and aggregation. The authors accept no liability for any damages arising from the use of information in this report. For energy performance evaluation of individual building projects, please consult qualified professionals and verify the original source data. Copyright of the underlying data belongs to the original data providers.