Optimizing Heat Pump Load Flexibility for Cost, Comfort, and Carbon Emissions
Optimizing heat pump load flexibility for cost, comfort, and carbon emission reductions
The Regents of the University of California, on behalf of the Davis Campus
Recipient
Davis, CA
Recipient Location
3rd
Senate District
4th
Assembly District
$1,842,743
Amount Spent
Active
Project Status
Project Update
By the end of 2025, the team had completed technical development and multi‑phase testing of the SPARC‑DR supervisory control framework, including simulation, laboratory, and field demonstrations across two low‑income multifamily properties in California. The project successfully deployed Advanced Water Heating Controls (AWHC) in 18 homes and Advanced Space Conditioning Controls (ASCC) in two units, validating the system’s ability to reduce peak electricity use, shift load to cleaner periods, and maintain occupant comfort. Field data showed that AWHC reduced peak-period energy use by up to 31 percent at one site, while ASCC demonstrated effective precooling and preheating strategies that shifted load without increasing occupant burden. In parallel, stakeholder interviews and a statewide market characterization were completed, identifying key barriers related to installation cost, workforce limitations, and interoperability across communication standards. The team also conducted extensive knowledge transfer activities, including peer‑reviewed publications, conference presentations, and the release of open‑source tools, supporting early pathways toward commercialization.
The ASCC demonstrations continued through the end of January 2026.
The Issue
Residential heat pumps for space conditioning and water heating are typically operated using simple rule‑based controls that react only to temperature changes and do not account for electricity pricing, grid emissions, or real‑time grid needs. As California accelerates building electrification and transitions toward a cleaner but more variable electricity grid, unmanaged heat pump demand can increase evening peaks, requiring costly grid upgrades and reliance on high‑emission peaker plants. Existing demand response programs offer limited flexibility because they rely on basic load‑shedding signals that cannot continuously optimize appliance performance across all 8,760 hours in a year. These limitations disproportionately impact low‑income households, whose buildings often have poorer thermal performance and whose occupants have less flexibility to shift usage manually. To support decarbonization while maintaining affordability and comfort, heat pumps must be equipped with advanced, automated load-flexibility controls that can respond dynamically to grid and customer conditions.
Project Innovation
This project created and demonstrated SPARC‑DR, an open‑source, cloud‑based supervisory control framework that enables advanced, predictive load‑flexibility controls for heat pump water heaters and space conditioning systems. Using real‑time and forecasted data—including occupant preferences, hot water and HVAC use patterns, electricity prices, grid emissions, weather conditions, and demand‑response signals—the system optimizes equipment operation to reduce peak loads, lower energy costs, and decrease greenhouse gas emissions. AWHC treats the water heater as a thermal battery, while ASCC strategically adjusts thermostat setpoints to preheat or precool before peak periods, ensuring comfort while shifting load. The project demonstrated these controls in low‑income multifamily housing, showing that benefits can be delivered equitably and without disrupting occupant comfort. SPARC‑DR’s modular design, automated model‑updating, and API‑based architecture future‑proof the technology for integration with grid‑interactive appliances, other smart home devices, and evolving rate structures such as real‑time pricing.
Project Goals
Project Benefits
This project supports California’s clean energy and electrification goals by enabling heat pumps to operate more flexibly, reducing both peak demand and greenhouse gas emissions. By shifting heating, cooling, and water‑heating loads to off‑peak or cleaner-energy periods, SPARC‑DR reduces grid stress and helps avoid reliance on costly and polluting peaker plants. Field results demonstrated meaningful peak‑period reductions, while maintaining comfort and hot water availability for participating households. The project also provides benefits to low‑income communities by proving that advanced controls can be deployed in affordable housing without disrupting comfort or increasing staff workload. Through open‑source release of the control framework, algorithms, datasets, and documentation, the project accelerates market readiness and lowers barriers for manufacturers, utilities, and researchers to adopt and extend these innovations. Overall, the work delivers economic and environmental benefits that support statewide decarbonization while improving customer experience and expanding opportunities for smart, grid‑interactive technologies.
Consumer Appeal
By shifting heat‑pump operation away from peak hours and toward cleaner, lower‑cost electricity periods, the system can help reduce energy use during high‑priced times, though overall bill impacts may vary depending on household usage patterns and seasonal conditions. The approach may also support building owners by moderating operational costs, particularly in affordable housing settings where energy expenses influence long‑term financial planning.
Reliability
Load shifting during peak periods helps reduce stress on the grid, lowering reliance on costly and carbon‑intensive peaker plants and supporting more stable, reliable operations statewide.
Affordability
By shifting heat‑pump operation away from peak hours and toward cleaner, lower‑cost electricity periods, the system can help reduce energy use during high‑priced times, though overall bill impacts may vary depending on household usage patterns and seasonal conditions. The approach may also support building owners by moderating operational costs, particularly in affordable housing settings where energy expenses influence long‑term financial planning.
