Heatproof
Deutsch
Sprache
DeutschEnglish
Darstellung
DunkelHellSystem
Ansicht
Einfach: nur der Rechnungs-CheckVollständig: alle Seiten
Home / system #786

Viessmann 150a

Byfield, Northamptonshire · Detached · 200 m² · 1900 to 1939 · 16 kW · radiators · installed by Custom Renewables

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

Last 30 days

721 hourly rows · MID-class heat meter present: yes
3.76efficiency (COP) over 721 hours, from the heat meter
better than 59% of the metered fleet in January 2026
Electricity used
451 kWh
Heat delivered
1694 kWh (heat meter)
Estimate without heat meter
flow sensor 3.37 · temperature model 4.02
Mean outdoor temperature
10.2 °C · 469 space-heating hours
Flow temperature at 0 °C outside
26.5 °C (curve slope 1.06 per K)
Flow − return while heating
2.1 K
House needs at −3 °C
6.1 kW (unit rated 16 kW) · fit r² 0.11
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.
seriousCompressor starts about 7.5 times per hour
Short cycling wears the compressor and cuts efficiency. Usual fixes: remove or bypass a buffer, open zone valves, lower the curve, raise minimum run time.
warningUnit is rated 16 kW but the house needs about 6.1 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.
noteOwner’s note on the source site: “Negative heat not reported”

Day by day

electricity per daydaily COP3.0 floor
electricity, kWh per day012232026-10-08: 6 kWh, outside 11.2 °C2026-10-09: 7.8 kWh, outside 14.2 °C2026-10-10: 11.4 kWh, outside 10.1 °C2026-10-11: 12 kWh, outside 9.7 °C2026-10-12: 9.3 kWh, outside 14 °C2026-10-13: 5.4 kWh, outside 15.1 °C2026-10-14: 10.1 kWh, outside 12.2 °C2026-10-15: 6.2 kWh, outside 16.2 °C2026-10-16: 9.8 kWh, outside 10.7 °C2026-10-17: 19.4 kWh, outside 8 °C2026-10-18: 19.1 kWh, outside 8.8 °C2026-10-19: 15.2 kWh, outside 10.1 °C2026-10-20: 14.2 kWh, outside 10.4 °C2026-10-21: 23 kWh, outside 7.7 °C2026-10-22: 13.4 kWh, outside 9.7 °C2026-10-23: 21.6 kWh, outside 9.3 °C2026-10-24: 20 kWh, outside 9.2 °C2026-10-25: 14.5 kWh, outside 9.8 °C2026-10-26: 12.1 kWh, outside 11 °C2026-10-27: 11.5 kWh, outside 12.4 °C2026-10-28: 15.4 kWh, outside 10.1 °C2026-10-29: 13.3 kWh, outside 10.9 °C2026-10-30: 12.1 kWh, outside 10.3 °C2026-10-31: 14.8 kWh, outside 8.8 °C2026-11-01: 18.5 kWh, outside 8.1 °C2026-11-02: 18.7 kWh, outside 8.2 °C2026-11-03: 21.1 kWh, outside 8.1 °C2026-11-04: 21.8 kWh, outside 8.7 °C2026-11-05: 23.4 kWh, outside 8.1 °C2026-11-06: 19.8 kWh, outside 8 °C2026-11-07: 9.6 kWh, outside 3.9 °Cdaily COP (heat ÷ electricity)1352026-10-08: COP 3.392026-10-09: COP 2.812026-10-10: COP 3.662026-10-11: COP 3.442026-10-12: COP 2.722026-10-13: COP 2.552026-10-14: COP 3.482026-10-15: COP 2.692026-10-16: COP 3.512026-10-17: COP 3.642026-10-18: COP 3.612026-10-19: COP 3.662026-10-20: COP 4.042026-10-21: COP 3.962026-10-22: COP 3.832026-10-23: COP 3.962026-10-24: COP 3.962026-10-25: COP 4.112026-10-26: COP 4.052026-10-27: COP 3.832026-10-28: COP 3.892026-10-29: COP 3.82026-10-30: COP 3.792026-10-31: COP 3.882026-11-01: COP 3.982026-11-02: COP 3.782026-11-03: COP 3.92026-11-04: COP 3.882026-11-05: COP 3.972026-11-06: COP 3.952026-11-07: COP 3.6510-0810-1210-1610-2010-2410-2811-0111-05
Daily COP needs a heat meter; days without one show electricity only.

The installed heating curve

one heating hourfitted curve50 °C
203040506013579111315outdoor 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.