# Refrigerant Undercharge Detection

30% Energy Waste Identified & Corrected via Continuous Monitoring

Mitsubishi MXZ-SM36NAMHZ  ·  Colorado Deployment  ·  February 2026

## Undercharge

- **40%** refrigerant deficit
- **Efficiency Gain**: ~30% energy intensity reduction
- **Annual Waste**: ~2,400 kWh (~$360/yr at $0.15/kWh)
- **CO₂ Avoided**: 1.26 MT CO₂/yr (eGRID RMPA)

## The Situation

### A Fault That Would Have Gone Undetected Indefinitely

Thalo's continuous cellular monitoring detected anomalous power draw on a Mitsubishi MXZ-SM36NAMHZ VRF heat pump at a Colorado residential deployment. The system flagged abnormal energy consumption patterns before any tenant complaint or visible failure occurred.

Field inspection confirmed a 40% refrigerant undercharge. Without telemetry, this fault would have continued undetected — silently wasting energy and stressing the compressor. Field surveys find 78% of installed systems have charge issues.

## The Findings

### Key Results After Correction

- Energy intensity reduced from 1.59 → 1.11 kWh/°F-day (~30%)
- Monthly winter savings of ~480 kWh ($72/mo)
- Avoided emissions of ~1.26 MT CO₂/yr (≈ 3,200 mi driving)

This fault would have gone undetected indefinitely without telemetry. Field surveys find 78% of installed systems have charge issues.

## Methodology

### Temperature-Normalized Energy Analysis

Daily kWh was normalized by heating degree-days (base 65°F). Before/after compared via OLS regression with R² goodness-of-fit. Recovery transient (Jan 30–31) excluded. Emissions use EPA eGRID RMPA factor: 1,159 lbs CO₂/MWh.

Colorado's RMPA grid (1,159 lbs CO₂/MWh) is 43% more carbon-intensive than the national average — making every kWh saved here carry outsized climate impact.

## Fleet-Scale Impact

### What This Means Across 24,000 Units

Assuming 25% of units have charge faults at half this severity: ~7.2M kWh/yr wasted, ~$1.1M/yr excess electricity, and ~3,790 MT CO₂/yr of avoidable emissions — all detectable and correctable through continuous monitoring.

### Temperature-Normalized Energy: Before vs. After Service

Each point = one day's energy use vs. heating degree-days (base 65°F). Red = undercharged; Green = corrected.

Mitsubishi MXZ-SM36NAMHZ · Colorado Deployment

### Measured Impact

- **Energy intensity (before)**: 1.59 kWh/°F-day
- **Energy intensity (after)**: 1.11 kWh/°F-day
- **Monthly winter savings**: ~480 kWh ($72/mo)
- **Annual energy waste corrected**: ~2,400 kWh
- **CO₂ avoided per year**: 1.26 MT

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