Heatproof
Deutsch
Sprache
DeutschEnglish
Darstellung
DunkelHellSystem
Ansicht
Einfach: nur der Rechnungs-CheckVollständig: alle Seiten
Home / system #651

Viessmann Vitocal 150A

Tongham, Surrey · Detached · 150 m² · 1940 to 1982 · 16 kW · radiators · installed by Alton & Jones

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

Last 7 days

169 hourly rows · MID-class heat meter present: yes
4.73efficiency (COP) over 169 hours, from the heat meter
better than 97% of the metered fleet in January 2026
Electricity used
180 kWh
Heat delivered
854 kWh (heat meter)
Estimate without heat meter
flow sensor 4.75 · temperature model 4.19
Mean outdoor temperature
8.1 °C · 155 space-heating hours
Flow temperature at 0 °C outside
32.5 °C (curve slope 0.03 per K)
Flow − return while heating
2.5 K
House needs at −3 °C
10.3 kW (unit rated 16 kW) · fit r² 0.09
Hot water
no hot-water flag in data
warningOnly 2.5 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.
noteOwner’s note on the source site: “No internal controls monitored on this required on Viessmann review also missing booster heater heat”

Day by day

electricity per daydaily COP3.0 floor
electricity, kWh per day015292026-10-31: 10.3 kWh, outside 10 °C2026-11-01: 23.3 kWh, outside 7.4 °C2026-11-02: 23.6 kWh, outside 8.6 °C2026-11-03: 24.9 kWh, outside 8.5 °C2026-11-04: 25.3 kWh, outside 8.1 °C2026-11-05: 26.7 kWh, outside 7.7 °C2026-11-06: 29.4 kWh, outside 8.1 °C2026-11-07: 16.9 kWh, outside 4.6 °Cdaily COP (heat ÷ electricity)1352026-10-31: COP 4.582026-11-01: COP 4.942026-11-02: COP 4.942026-11-03: COP 52026-11-04: COP 4.892026-11-05: COP 4.752026-11-06: COP 4.542026-11-07: COP 3.9510-3111-0111-0211-0311-0411-0511-0611-07
Daily COP needs a heat meter; days without one show electricity only.

The installed heating curve

one heating hourfitted curve50 °C
2030405060246810121416outdoor 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.