Heatproof
Home / system #585

Vaillant Arotherm+

Hinstock, Shropshire · Detached · 200 m² · 1983 to 2011 · 7 kW · radiators · installed by RG Plumbing Services

Last 30 days

721 hourly rows · MID-class heat meter present: yes
4.46efficiency (COP) over 721 hours, from the heat meter
better than 92% of the metered fleet in January 2026
Electricity used
375 kWh
Heat delivered
1671 kWh (heat meter)
Estimate without heat meter
flow sensor 4.34 · temperature model 4.31
Mean outdoor temperature
10.0 °C · 431 space-heating hours
Flow temperature at 0 °C outside
33.3 °C (curve slope -0.41 per K)
Flow − return while heating
2.2 K
House needs at −3 °C
4.7 kW (unit rated 7 kW) · fit r² 0.11
Hot water
36% of electricity, COP 3.06
warningOnly 2.2 K between flow and return
Circulation pump may be set too high or emitters are undersized for the low flow temperature. Ask the installer to check pump speed.
warningHot water uses 36% of electricity at COP 3.06
Lower the tank target to 45–48 °C, heat water once a day in the warmest hours, and disable weekly legionella cycles unless required.

Day by day

electricity per daydaily COP3.0 floor
electricity, kWh per day010202026-10-08: 3.4 kWh, outside 11.5 °C2026-10-09: 5.3 kWh, outside 14.3 °C2026-10-10: 12.5 kWh, outside 10.6 °C2026-10-11: 9 kWh, outside 10.5 °C2026-10-12: 3.7 kWh, outside 14.8 °C2026-10-13: 2.9 kWh, outside 14.6 °C2026-10-14: 7.2 kWh, outside 12.5 °C2026-10-15: 4.1 kWh, outside 15.3 °C2026-10-16: 8.8 kWh, outside 9.2 °C2026-10-17: 14.7 kWh, outside 6.6 °C2026-10-18: 16.7 kWh, outside 8.8 °C2026-10-19: 14 kWh, outside 10.2 °C2026-10-20: 7.7 kWh, outside 9.5 °C2026-10-21: 13.4 kWh, outside 8 °C2026-10-22: 13 kWh, outside 8.7 °C2026-10-23: 13.8 kWh, outside 8.2 °C2026-10-24: 19.9 kWh, outside 9 °C2026-10-25: 20 kWh, outside 9.9 °C2026-10-26: 10 kWh, outside 11.4 °C2026-10-27: 12.8 kWh, outside 12 °C2026-10-28: 11.4 kWh, outside 11 °C2026-10-29: 10.8 kWh, outside 10.8 °C2026-10-30: 12.6 kWh, outside 9.5 °C2026-10-31: 19.2 kWh, outside 7.9 °C2026-11-01: 19.8 kWh, outside 7.5 °C2026-11-02: 18 kWh, outside 6.6 °C2026-11-03: 13.7 kWh, outside 8.3 °C2026-11-04: 15.8 kWh, outside 9 °C2026-11-05: 15.9 kWh, outside 8.4 °C2026-11-06: 15.2 kWh, outside 8.6 °C2026-11-07: 9.6 kWh, outside 6 °Cdaily COP (heat ÷ electricity)1352026-10-08: COP 5.862026-10-09: COP 4.962026-10-10: COP 4.112026-10-11: COP 4.592026-10-12: COP 5.222026-10-13: COP 3.792026-10-14: COP 4.032026-10-15: COP 3.982026-10-16: COP 4.662026-10-17: COP 4.232026-10-18: COP 3.92026-10-19: COP 3.942026-10-20: COP 5.862026-10-21: COP 4.842026-10-22: COP 4.662026-10-23: COP 5.012026-10-24: COP 4.382026-10-25: COP 4.082026-10-26: COP 4.992026-10-27: COP 4.182026-10-28: COP 52026-10-29: COP 5.082026-10-30: COP 4.862026-10-31: COP 4.392026-11-01: COP 4.082026-11-02: COP 4.152026-11-03: COP 4.562026-11-04: COP 4.492026-11-05: COP 4.672026-11-06: COP 4.542026-11-07: COP 3.3710-0810-1210-1610-2010-2410-2811-0111-05
Daily COP needs a heat meter; days without one show electricity only.

The installed heating curve

one heating hourfitted curve50 °C
20304050600246810121416outdoor 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.