689 hourly rows · MID-class heat meter present: yes
4.04efficiency (COP) over 689 hours, from the heat meter better than 79% of the metered fleet in January 2026
Electricity used
135 kWh
Heat delivered
546 kWh (heat meter)
Estimate without heat meter
flow sensor 3.56 · temperature model 4.46
Mean outdoor temperature
10.5 °C · 215 space-heating hours
Flow temperature at 0 °C outside
33.5 °C (curve slope -0.54 per K)
Flow − return while heating
1.2 K
House needs at −3 °C
1.7 kW (unit rated 5 kW) · fit r² 0.16
Hot water
30% of electricity, COP 3.51
warningOnly 1.2 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.
infoUnit is rated 5 kW but the house needs about 1.7 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: “Not recording negative heat on heat meter”
Day by day
electricity per daydaily COP3.0 floor
Daily COP needs a heat meter; days without one show electricity only.
The installed heating curve
one heating hourfitted curve50 °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.