Heatproof
Home / system #812

Vaillant Arotherm+

Hove, East Sussex · Detached · 118 m² · 1940 to 1982 · 5 kW · radiators · installed by Hartswood

5 Jan – 4 Feb 2026 (winter reference)

721 hourly rows · MID-class heat meter present: yes
4.01efficiency (COP) over 721 hours, from the heat meter
better than 76% of the metered fleet in January 2026
Electricity used
617 kWh
Heat delivered
2473 kWh (heat meter)
Estimate without heat meter
flow sensor 4.05 · temperature model 3.68
Mean outdoor temperature
6.3 °C · 629 space-heating hours
Flow temperature at 0 °C outside
37.4 °C (curve slope -0.59 per K)
Flow − return while heating
3.4 K
House needs at −3 °C
5.4 kW (unit rated 5 kW) · fit r² 0.61
Hot water
14% of electricity, COP 3.85
infoNo configuration faults detected in this window
Keep the current settings. We will alert you if efficiency drifts.

Day by day

electricity per daydaily COP3.0 floor
electricity, kWh per day022442026-01-05: 44.1 kWh, outside -1.3 °C2026-01-06: 42.5 kWh, outside -0.6 °C2026-01-07: 34.1 kWh, outside 3.9 °C2026-01-08: 26 kWh, outside 5 °C2026-01-09: 34.2 kWh, outside 4.1 °C2026-01-10: 39.5 kWh, outside 1.1 °C2026-01-11: 27.7 kWh, outside 4.4 °C2026-01-12: 15.5 kWh, outside 9.7 °C2026-01-13: 13.8 kWh, outside 9.2 °C2026-01-14: 18.3 kWh, outside 5.6 °C2026-01-15: 14.8 kWh, outside 8.3 °C2026-01-16: 15.6 kWh, outside 7.3 °C2026-01-17: 14.3 kWh, outside 8.3 °C2026-01-18: 13.3 kWh, outside 8.4 °C2026-01-19: 12.3 kWh, outside 9 °C2026-01-20: 12.8 kWh, outside 8.8 °C2026-01-21: 14.7 kWh, outside 8.4 °C2026-01-22: 15.8 kWh, outside 8.7 °C2026-01-23: 16.8 kWh, outside 7.8 °C2026-01-24: 16.5 kWh, outside 7.7 °C2026-01-25: 16.1 kWh, outside 6.8 °C2026-01-26: 17.7 kWh, outside 5.9 °C2026-01-27: 16.4 kWh, outside 7.7 °C2026-01-28: 18.5 kWh, outside 4.8 °C2026-01-29: 22.3 kWh, outside 4.2 °C2026-01-30: 15.6 kWh, outside 8.1 °C2026-01-31: 15 kWh, outside 7.9 °C2026-02-01: 14.4 kWh, outside 7.8 °C2026-02-02: 17.3 kWh, outside 7 °C2026-02-03: 20.3 kWh, outside 5.3 °C2026-02-04: 0.7 kWh, outside 6.1 °Cdaily COP (heat ÷ electricity)1352026-01-05: COP 2.662026-01-06: COP 2.762026-01-07: COP 3.192026-01-08: COP 3.812026-01-09: COP 3.152026-01-10: COP 2.852026-01-11: COP 3.762026-01-12: COP 4.922026-01-13: COP 4.992026-01-14: COP 4.352026-01-15: COP 4.822026-01-16: COP 4.682026-01-17: COP 4.832026-01-18: COP 4.922026-01-19: COP 5.142026-01-20: COP 4.972026-01-21: COP 4.842026-01-22: COP 4.812026-01-23: COP 4.562026-01-24: COP 4.532026-01-25: COP 4.482026-01-26: COP 4.312026-01-27: COP 4.632026-01-28: COP 4.372026-01-29: COP 3.992026-01-30: COP 4.752026-01-31: COP 4.752026-02-01: COP 4.862026-02-02: COP 4.52026-02-03: COP 4.232026-02-04: COP 4.8101-0501-0901-1301-1701-2101-2501-2902-02
Daily COP needs a heat meter; days without one show electricity only.

The installed heating curve

one heating hourfitted curve50 °C
2030405060-8-5-214710outdoor 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.