Heatproof
Home / system #61

Nibe F2040

Sleaford, Lincolnshire · Detached · 214 m² · 1940 to 1982 · 12 kW · underfloor

5 Jan – 4 Feb 2026 (winter reference)

721 hourly rows · MID-class heat meter present: yes
3.25efficiency (COP) over 721 hours, from the heat meter
better than 24% of the metered fleet in January 2026
Electricity used
1128 kWh
Heat delivered
3666 kWh (heat meter)
Estimate without heat meter
flow sensor 3.37 · temperature model 3.57
Mean outdoor temperature
4.7 °C · 542 space-heating hours · cooling 0 kWh removed (2 kWh electricity), kept out of the COP
Flow temperature at 0 °C outside
34.7 °C (curve slope -0.33 per K)
Flow − return while heating
4.0 K
House needs at −3 °C
6.8 kW (unit rated 12 kW) · fit r² 0.05
Hot water
15% of electricity, COP 3.43
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 £34 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 day033662026-01-05: 57.3 kWh, outside -1.7 °C2026-01-06: 58.3 kWh, outside -0.1 °C2026-01-07: 60.5 kWh, outside 3.5 °C2026-01-08: 61.9 kWh, outside 1.6 °C2026-01-09: 60.5 kWh, outside 2.4 °C2026-01-10: 65.7 kWh, outside 0.3 °C2026-01-11: 63.5 kWh, outside 4.1 °C2026-01-12: 17 kWh, outside 9.3 °C2026-01-13: 45.5 kWh, outside 6.7 °C2026-01-14: 39.7 kWh, outside 1.9 °C2026-01-15: 30.4 kWh, outside 6 °C2026-01-16: 30.5 kWh, outside 4.9 °C2026-01-17: 28.7 kWh, outside 6.3 °C2026-01-18: 26.2 kWh, outside 5.6 °C2026-01-19: 24.2 kWh, outside 7.7 °C2026-01-20: 19.9 kWh, outside 8.1 °C2026-01-21: 24.8 kWh, outside 6.9 °C2026-01-22: 23.7 kWh, outside 7.2 °C2026-01-23: 29.5 kWh, outside 6.6 °C2026-01-24: 30.6 kWh, outside 6 °C2026-01-25: 34.1 kWh, outside 5.3 °C2026-01-26: 35.8 kWh, outside 2.8 °C2026-01-27: 36.2 kWh, outside 5.4 °C2026-01-28: 31.8 kWh, outside 3.8 °C2026-01-29: 36.4 kWh, outside 3.4 °C2026-01-30: 33.8 kWh, outside 5.1 °C2026-01-31: 29.1 kWh, outside 6.9 °C2026-02-01: 27.2 kWh, outside 6.5 °C2026-02-02: 28.1 kWh, outside 5.8 °C2026-02-03: 36.3 kWh, outside 2.7 °C2026-02-04: 1.8 kWh, outside 0.8 °Cdaily COP (heat ÷ electricity)1352026-01-05: COP 2.582026-01-06: COP 2.692026-01-07: COP 2.862026-01-08: COP 2.482026-01-09: COP 2.772026-01-10: COP 2.322026-01-11: COP 2.692026-01-12: COP 4.042026-01-13: COP 3.452026-01-14: COP 2.752026-01-15: COP 3.822026-01-16: COP 3.412026-01-17: COP 3.952026-01-18: COP 3.822026-01-19: COP 3.892026-01-20: COP 4.252026-01-21: COP 3.982026-01-22: COP 3.942026-01-23: COP 3.852026-01-24: COP 3.682026-01-25: COP 3.682026-01-26: COP 3.362026-01-27: COP 3.592026-01-28: COP 3.212026-01-29: COP 3.472026-01-30: COP 3.582026-01-31: COP 3.762026-02-01: COP 3.942026-02-02: COP 3.892026-02-03: COP 3.372026-02-04: COP 3.0101-0501-0901-1301-1701-2101-2501-2902-02
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.