October 2025 focused on strengthening the Air Flow Network (AFN) integration within EnergyPlus, improving HVAC modeling accuracy, reliability, and test coverage. Delivered feature enhancements for AFN run fraction tracking, fixed critical leakage and node timing issues, and expanded unit tests to bolster confidence across HVAC components. These efforts improve design decision support, reduce forecasting risk, and lay groundwork for more robust performance simulations in future releases.

September 2025 (NREL/EnergyPlus) monthly development summary focused on correctness, readability, and test reliability. Delivered targeted code fixes and test improvements across three core HVAC models, enhancing model fidelity, maintainability, and CI stability. Key outcomes include corrected energy/power calculations, expanded unit tests for edge cases, and formatting cleanups that reduce future maintenance risk.

Month 2025-08: Delivered significant HVAC feature enhancements and metering reliability improvements for EnergyPlus. Key outcomes include enabling variable-speed DX cooling coils in SZVAV control and adding a variable-speed heating coil type (AirToAirVariableSpeed) for Unitary Systems, supported by model updates, test files, and comprehensive documentation. In parallel, improved metering reporting accuracy and warmup handling to ensure reliable energy metrics, including conditional meter updates and resets after warmup. These efforts enhanced system fidelity, optimizations for variable-speed configurations, and overall data quality for energy modeling.

June 2025 monthly summary for NREL/openstudio-standards focusing on delivering targeted fixes and improvements that enhance model accuracy, compliance, and maintainability. Key outcomes include NECB/PTHP search logic fixes that prevent incorrect rule applications and updates to DX coil performance data, with corresponding regression/test alignment and code quality improvements.

May 2025 performance summary: Focused on robustness and correctness improvements in EnergyPlus PlantLoopHeatPumpEIR models, enhancements to fuel-fired heat pump flow rate calculations, and expansion of sizing factor minimum to enable proper part-load sizing. The work improves modeling accuracy, test reliability, and maintainability, delivering clearer business value through more accurate energy predictions and flexible design assumptions.