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Daikin Altherma 3

Southampton, Hampshire · Detached · 185 m² · 1983 to 2011 · 9 kW · radiators · installed by Octopus Energy Services

5 Jan – 4 Feb 2026 (winter reference)

721 hourly rows · MID-class heat meter present: no
3.27efficiency (COP) over 721 hours, from the heat meter
better than 24% of the metered fleet in January 2026
Electricity used
842 kWh
Heat delivered
2751 kWh (heat meter)
Estimate without heat meter
flow sensor 3.23 · temperature model 3.46
Mean outdoor temperature
6.4 °C · 479 space-heating hours · cooling 1 kWh removed (0 kWh electricity), kept out of the COP
Flow temperature at 0 °C outside
37.7 °C (curve slope -0.27 per K)
Flow − return while heating
4.2 K
House needs at −3 °C
6.9 kW (unit rated 9 kW) · fit r² 0.12
Hot water
9% of electricity, COP 2.98
infoNo configuration faults detected in this window
Keep the current settings. We will alert you if efficiency drifts.
valueReaching the fleet’s January median (3.69) would have saved about £24 in this window at 0.25 GBP/kWh. An estimate, not a promise.

Day by day

electricity per daydaily COP3.0 floor
electricity, kWh per day029592026-01-05: 58.9 kWh, outside -0.1 °C2026-01-06: 51.5 kWh, outside 1 °C2026-01-07: 35.9 kWh, outside 4.9 °C2026-01-08: 30.4 kWh, outside 5.3 °C2026-01-09: 43.7 kWh, outside 4.1 °C2026-01-10: 44.7 kWh, outside 1.2 °C2026-01-11: 34.9 kWh, outside 5.8 °C2026-01-12: 16.1 kWh, outside 10.3 °C2026-01-13: 18.5 kWh, outside 9.2 °C2026-01-14: 26.9 kWh, outside 5.5 °C2026-01-15: 21.9 kWh, outside 8.1 °C2026-01-16: 25.3 kWh, outside 6.8 °C2026-01-17: 23.6 kWh, outside 7.6 °C2026-01-18: 19.7 kWh, outside 8.2 °C2026-01-19: 20.7 kWh, outside 8.6 °C2026-01-20: 21.5 kWh, outside 8.3 °C2026-01-21: 20 kWh, outside 8.1 °C2026-01-22: 20.9 kWh, outside 8.6 °C2026-01-23: 22.8 kWh, outside 7.7 °C2026-01-24: 23.7 kWh, outside 7.7 °C2026-01-25: 26.1 kWh, outside 6.4 °C2026-01-26: 27.9 kWh, outside 6.3 °C2026-01-27: 21.7 kWh, outside 7.7 °C2026-01-28: 29.1 kWh, outside 4.9 °C2026-01-29: 35 kWh, outside 5.1 °C2026-01-30: 25 kWh, outside 7.6 °C2026-01-31: 19.9 kWh, outside 7.5 °C2026-02-01: 24.3 kWh, outside 7.1 °C2026-02-02: 22.4 kWh, outside 6.9 °C2026-02-03: 29 kWh, outside 5.3 °C2026-02-04: 0 kWh, outside 6 °Cdaily COP (heat ÷ electricity)1352026-01-05: COP 2.532026-01-06: COP 2.762026-01-07: COP 3.122026-01-08: COP 3.152026-01-09: COP 3.022026-01-10: COP 2.672026-01-11: COP 3.212026-01-12: COP 4.482026-01-13: COP 4.182026-01-14: COP 3.292026-01-15: COP 3.892026-01-16: COP 3.342026-01-17: COP 3.412026-01-18: COP 3.682026-01-19: COP 3.732026-01-20: COP 3.622026-01-21: COP 3.722026-01-22: COP 3.862026-01-23: COP 3.592026-01-24: COP 3.572026-01-25: COP 3.372026-01-26: COP 3.312026-01-27: COP 3.562026-01-28: COP 2.992026-01-29: COP 2.932026-01-30: COP 3.542026-01-31: COP 3.332026-02-01: COP 3.372026-02-02: COP 3.292026-02-03: COP 3.2101-0501-0901-1301-1701-2101-2501-2902-02
Daily COP needs a heat meter; days without one show electricity only.

The installed heating curve

one heating hourfitted curve50 °C
2030405060-6-4-2024681012outdoor temperature, °Cflow temperature, °C
Each point is one hour of space heating. Lower and flatter is cheaper; well-set radiator systems sit around 35–42 °C at 0 °C outside.
Public system published by its owner on HeatpumpMonitor.org. Cycling (starts per hour) comes from the site’s 365-day statistic. Findings use installer rules of thumb; see methodology.