Let's Control It

Has anyone made a heat meter that reports heat kWh to Domoticz? (Or MJ if you like)

It would be great to measure the efficiency of a heat pump (or Dino fuel heater for those stuck in the 1900's )

Water flow could be measured with a cheap YF-G1 flow meter on a pulse input, and two 18ds20 would measure delta-T.

Assuming
V= Volume [l]
dT= Delta-T [degree]
E= Energy [kWh]

Then
E=(1,16 E-3)*dT*V

needs to be calculated and sent to Domoticz

The water is ( as mentioned in your topic header ) hot !!

Don't you think the YF-G1 will melt or at least have troubles with the heat?

My heat pump goes up to 55degC.
The YF-G1 is specified for >80degC. So no problem.
Anyone needing higher temperatures can take another flow meter. They all have pulse outputs.

Any heating system (except solar thermal) with water temperatures over 60degC is so badly dimensioned that efficiency measurement is of no concern at all.

The guys from Open Energy Monitor did some research: https://heatpumpmonitor.org/
https://github.com/openenergymonitor/He ... r/Hardware