End-Use Savings Shapes Measure Documentation: Heat Pump Rooftop Units with Original Fuel Backup

Summary

This NREL technical report, published in September 2024, documents the 'Heat Pump Rooftop Units with Original Fuel Backup' measure within the ComStock™ model for the U.S. commercial building stock. The initiative provides detailed energy efficiency, electrification, and demand flexibility load shapes for high-impact measures. This measure, applicable to approximately 36% of the ComStock floor area, models the replacement of gas-fired and electric resistance rooftop units with high-efficiency heat pump rooftop units that use supplemental heating matching the original fuel type. Results indicate an 8.5% total site energy savings, or 396 trillion British thermal units (TBtu), for the U.S. commercial building stock. This includes a significant 27% reduction in stock heating gas (226 TBtu) but a 22% increase in heating electricity (-43 TBtu). The measure is projected to avoid 3.5 to 14.3 million metric tons (MMT) of CO2e from grid electricity and 15.1 MMT from on-site natural gas consumption.

Key Facts

Source Document

https://example-government.gov/policy-document-link