Reducing Heat Pump Electricity Consumption in Winter

The configuration changes were applied on January 26.
This section evaluates their impact using real electricity consumption data and outdoor temperature data from the heat pump itself, ensuring consistent and comparable measurements.

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1. Raw Consumption Overview (Timeline)

Daily electricity consumption data from SolarEdge shows:

• January (before optimization):

  • Typical daily consumption: 45–55 kWh
  • Multiple days exceeding 50 kWh, even at moderate winter temperatures

• Late January (immediately after optimization):

  • Short-term reduction in daily consumption
  • Several days in the 40–45 kWh range

• February (after optimization, very cold period):

  • Daily consumption often again exceeded 50 kWh
  • This coincided with significantly lower outdoor temperatures, including periods below -10°C and down to approximately -15°C

📈 Consumption timeline (SolarEdge):

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2. Weather Context

Outdoor temperature data used in this analysis comes directly from the outdoor temperature sensor of the NIBE F1145 PC heat pump.

This ensures:

• consistent sensor placement,
• direct relevance to heat pump control logic,
• and no discrepancies caused by external weather services.

Temperature data shows that February was substantially colder than January.

🌡 Outdoor temperature timeline (NIBE F1145 PC):

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3. Consumption vs Outdoor Temperature (Key Result)

To account for weather differences, electricity consumption was analyzed relative to outdoor temperature measured by the heat pump itself, rather than by calendar date.

The comparison shows that:

• Before optimization (January):

  • ~50–55 kWh/day occurred already at -2 to -5°C

• After optimization (February):

  • Similar consumption levels (~50–55 kWh/day) occurred only at much lower temperatures, typically -8 to -14°C

This indicates a clear efficiency shift.

📊 Consumption vs temperature (before vs after):

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4. Comparative Table

Daily Consumption	Before Optimization (January)	After Optimization (February)	Temperature Shift
~48 kWh	approx. -1°C	approx. -7°C	-6°C
~50 kWh	approx. -2 / -3°C	approx. -8 / -9°C	-6 to -7°C
~52 kWh	approx. -4°C	approx. -10°C	-6°C
~54–55 kWh	approx. -5°C	approx. -13 to -14°C	-8 to -9°C

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5. Interpretation

The data supports the following conclusions:

• The optimization did not eliminate high consumption during extreme cold, which would be physically unrealistic.
• However, it reduced internal inefficiencies, such as:
  • over-heating,
  • excessive cycling,
  • and conflicts between space heating and DHW.
• As a result, the system now delivers comparable thermal output at much lower outdoor temperatures without a proportional increase in electricity usage.

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6. Summary

• Similar electricity consumption levels now correspond to 6–9°C lower outdoor temperatures
• This confirms a structural efficiency improvement
• Weather remains the dominant factor, but its impact on electricity usage has been reduced
• All results are based on real production data from:
  • SolarEdge (electricity consumption)
  • NIBE F1145 PC (outdoor temperature)

Further quantification would require normalization using heating degree days (HDD), but the available evidence already confirms a positive effect of the configuration changes.