American Energy Wise · Southern Heat Pumps · Lexington, SC

Catch the efficiency heat pumps quietly lose

Residential heat pumps and heat-pump water heaters can lose refrigerant charge, airflow, and coefficient of performance for months, and keep running the whole time.

An outdoor heat pump with three sensors: clamp-on current at the top of the cabinet, surface temperature on the refrigerant lines, and optional vibration on the lower cabinet.

The problem

Efficiency slips, and the unit stays on

These faults do not shut the equipment off, so they stay hidden until comfort fails or the power bill spikes.

Illustrative chart of energy use. A healthy unit stays nearly flat while this unit climbs, and the gap is labeled hidden loss. Beside it, a heat pump glows with tags for low refrigerant and starved for airflow.
  • Today the faults turn up on technician gauges, in a manufacturer portal, or when a customer complains.
  • Thermostats report status, not performance.
  • The losses that hide are refrigerant charge, airflow, and coefficient of performance.

Our fix

Sensing, plus a model that reads it

A few low-cost, non-invasive sensors feed a physics-informed machine-learning model.

Clamp-on current, surface temperature, and optional vibration feed a physics-informed machine-learning model. The model outputs a refrigerant charge fault, an airflow fault, and an efficiency loss. Tags read: no gauges, no OEM data, any brand.
  • Clamp-on current, surface temperature, and optional vibration. No refrigerant gauges.
  • The model flags charge and airflow faults and estimates the efficiency that was lost.
  • No manufacturer data. It is meant to work on any brand.

The same models can shift heat-pump and heat-pump water heater load off grid peaks while holding comfort and hot-water limits.

An illustrative day. Grid demand peaks in the evening. Heat-pump and water-heater load, shown dashed on that peak, moves earlier in the day. Cards note that comfort stays within agreed bounds and hot water stays within limits.

Phase I

Provisional feasibility targets

Bars for the research, set from published baselines.

Four provisional targets. Fault detection macro-F1 at least 0.80 on held-out installs. Efficiency error at most 10 percent COP MAPE. Sensor kit at most 150 dollars, bill of materials. At most 10 labeled examples per new model family.

Fault-detection macro-F1 of at least 0.80, and coefficient-of-performance error of at most 10%, on held-out installs. Sensor kit at most $150. At most 10 labeled examples for each new model family.

The funding

An NSF STTR Phase I grant

Solicitation NSF 26-510. The project is intelligent diagnostics and grid-flexible control for heat pumps and heat-pump water heaters.

  • Up to $305,000 over 6–18 months.
  • No equity. Intellectual property stays with the company.
  • With a South Carolina university partner. None chosen yet.
NSF STTR Phase I, up to 305,000 dollars over 6 to 18 months. No equity, and intellectual property stays with the company. At least 40 percent to American Energy Wise and at least 30 percent to a South Carolina university. A calendar shows March 4, 2027, the full proposal deadline at 5 PM ET.
Budget split and key dates

The $305,000 is all-in. At least 40% ($122,000) goes to American Energy Wise, and at least 30% ($91,500) goes to the university.

Project Pitch
Planned for November 5–10, 2026
Full proposal
March 4, 2027, 5 p.m. ET
Fallback deadline
July 7, 2027
Decision
About August–October 2027 (estimate)

Who

American Energy Wise

American Energy Wise is the LLC that Southern Heat Pumps operates under. From Lexington, South Carolina, the company installs and services residential heat pumps and heat-pump water heaters in the Lexington and Columbia area. Founded in 2024 by Robert Stevens and Russell Stevens. Principal investigator: Robert Ray Stevens.