Heatproof
Deutsch
Sprache
DeutschEnglish
Darstellung
DunkelHellSystem
Ansicht
Einfach: nur der Rechnungs-CheckVollständig: alle Seiten
Home / system #927

Vaillant Arotherm+

Exeter, Devon · Detached · 80 m² · 1983 to 2011 · 5 kW · radiators · installed by Cortex Heating

Last 30 daysLast 7 days5 Jan – 4 Feb 2026 (winter reference)1–31 Dec 2025

5 Jan – 4 Feb 2026 (winter reference)

721 hourly rows · MID-class heat meter present: no
3.22efficiency (COP) over 721 hours, from the heat meter
better than 24% of the metered fleet in January 2026
Electricity used
283 kWh
Heat delivered
910 kWh (heat meter)
Estimate without heat meter
flow sensor 184.42 · temperature model 3.55
Mean outdoor temperature
6.3 °C · 477 space-heating hours
Flow temperature at 0 °C outside
38.7 °C (curve slope -0.54 per K)
Flow − return while heating
2.1 K
House needs at −3 °C
2.2 kW (unit rated 5 kW) · fit r² 0.01
Hot water
no hot-water flag in data
warningOnly 2.1 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.
infoUnit is rated 5 kW but the house needs about 2.2 kW at −3 °C
Oversizing causes cycling in mild weather. Cannot be fixed cheaply now, but the curve and minimum run time can limit the damage.
valueReaching the fleet’s January median (3.69) would have saved about £9 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 day08162026-01-05: 15.2 kWh, outside -0.1 °C2026-01-06: 16 kWh, outside 1.8 °C2026-01-07: 8.3 kWh, outside 6 °C2026-01-08: 8.4 kWh, outside 6.8 °C2026-01-09: 11.2 kWh, outside 4 °C2026-01-10: 11.7 kWh, outside 2.3 °C2026-01-11: 8.6 kWh, outside 8.5 °C2026-01-12: 5.1 kWh, outside 9.7 °C2026-01-13: 5.1 kWh, outside 9 °C2026-01-14: 13.4 kWh, outside 3.5 °C2026-01-15: 8.7 kWh, outside 6.7 °C2026-01-16: 10 kWh, outside 4.7 °C2026-01-17: 8.5 kWh, outside 5.6 °C2026-01-18: 8.5 kWh, outside 7.1 °C2026-01-19: 9.2 kWh, outside 6.5 °C2026-01-20: 9.8 kWh, outside 6.8 °C2026-01-21: 8 kWh, outside 8.1 °C2026-01-22: 8 kWh, outside 8 °C2026-01-23: 9.1 kWh, outside 7.3 °C2026-01-24: 9.5 kWh, outside 7.7 °C2026-01-25: 10.5 kWh, outside 7 °C2026-01-26: 9 kWh, outside 7.5 °C2026-01-27: 9.1 kWh, outside 8.1 °C2026-01-28: 10.2 kWh, outside 5.2 °C2026-01-29: 8.2 kWh, outside 7.5 °C2026-01-30: 8.5 kWh, outside 7.1 °C2026-01-31: 8.7 kWh, outside 6.3 °C2026-02-01: 7.1 kWh, outside 6.8 °C2026-02-02: 10.7 kWh, outside 6.3 °C2026-02-03: 8.3 kWh, outside 7.7 °C2026-02-04: 0 kWh, outside 6.5 °Cdaily COP (heat ÷ electricity)1352026-01-05: COP 2.72026-01-06: COP 2.822026-01-07: COP 3.022026-01-08: COP 3.092026-01-09: COP 2.952026-01-10: COP 2.922026-01-11: COP 3.312026-01-12: COP 3.412026-01-13: COP 3.442026-01-14: COP 3.062026-01-15: COP 3.32026-01-16: COP 3.022026-01-17: COP 3.062026-01-18: COP 3.412026-01-19: COP 3.252026-01-20: COP 3.292026-01-21: COP 3.352026-01-22: COP 3.332026-01-23: COP 3.422026-01-24: COP 3.412026-01-25: COP 4.462026-01-26: COP 3.392026-01-27: COP 3.352026-01-28: COP 3.082026-01-29: COP 3.342026-01-30: COP 3.342026-01-31: COP 3.252026-02-01: COP 3.222026-02-02: COP 3.132026-02-03: COP 3.3301-0501-0901-1301-1701-2101-2501-2902-02
Daily COP needs a heat meter; days without one show electricity only.

The installed heating curve

one heating hourfitted curve50 °C
2030405060-4-2024681012outdoor 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.