Radiator monitoring

Hi there,
I’m looking for a Openhab integrated system that will tell me how much each radiator in the house is used/heat consumed, preferably in realtime.
The goal is to see where heating money is being spent and where to apply isolation if needed.

The heating system is warm water based. Know exactly what I spent on total heating but I cannot differentiate to the different rooms.

Any suggestions are most welcome,

I don’t think you will find a system that will just tell you. You will have to write some rules and/or do some charting to find your answer.

As for hardware to use, the following thread will probably be helpful to you.

Rules and charts are fine, it’s the raw data from radiator that is difficult to get.
The article you mentioned is about getting the actuators doing what you want.
My issue is the opposite: how can I collect the data from the radiators even those not managed.

It’s not temperature settings that I’m after, but the amount of warmth a radiator is radiating.
In some apartment buildings radiator meters (based on evaporation or new electronic based) are used, that serve to divide the buildings’ energy bill over the apartments. Something like that would work, but I there not available for end users and they are pretty low tech, i.e. not integratable in OH.
Hope this clarifies a bit.

In that case, you will need some very specific sensors of which I know nothing and have neither heard of nor seen posted anywhere on this forum. Most people I’ve seen solve this by monitoring the temperature in each room and firing up the boiler when one or more rooms is below the target temp. From that you should be able to determine which rooms are more frequently demanding heat and answer your question. But if you want higher fidelity than that I know of no after market sensor that will give it to you.

Perhaps that might be working with smappee (https://www.smappee.com/de/gas-und-wassermonitor) sensors.

I don’t have one but somebody in the forum mentioned that sensor a few days ago.

The typical installation in rented flats in appartment buildings in Germany to calculate the individual costs for heating is with such devices:

But they can only used to do a relative caclculation. You don’t get an absolute value how much energy is used.

Another idea: install a temperature sensor directly at the radiator. With the temperature (normally about 40…60°C) you can measure which radiator is working and for how long the radiator is used.


Thanks for your suggestions.

I’ll be going for the sensor option, winter is on its way, time to get the soldering iron warmed up and order a batch of atmega’s.

With the temperature sensors attached to the radiators I should be able to draw a ‘heat’-map of the house after compensating for radiator size.

Initial sensor idea is to activate 4-8 times/hour and have the sensor send the data using a RFM69 to a MQTT gateway/broker who passes it on to OH2, where processing takes place.

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I live in an apartment building and my heat bill is generated from a temperature sensor on the radiator. The model is called “ista 11490” and it seems to be documented here:

I would also like to place my own sensor on the radiator so I can keep track of the heat usage myself.

(and I am not into DIY on the hardware front)