Remeha Elga ace hybrid heat pump - poor performance with tado
Hi everyone,
I wanted to share my experience using the Remeha Elga Ace hybrid heat pump with my Tado system, in the hope that it might help others considering a similar setup—or perhaps lead to a solution.
My setup involves the Remeha Elga Ace, which operates on OpenTherm, and my Tado thermostat is able to communicate with it. However, the performance of the heat pump combined with Tado has been very disappointing. The main issue is that the heat pump consistently runs on low power while simultaneously calling for heat from the gas boiler. This results in inefficient energy use and higher costs—definitely not ideal for a hybrid system.
Here’s an example of what I’m experiencing:
In this chart, you can see that the heat pump is completely off for half of the time. When it does run, it mostly operates at low power. Meanwhile, my gas boiler consumed 8 m³ of gas over the same 24 hours (approximately €10 worth). Despite this energy usage, my room temperatures are not being kept stable.
This second chart illustrates steep upward temperature peaks caused by the system calling for heat. These peaks trigger full gas burn from the boiler, even though the heat pump could have maintained a more consistent temperature by just running continuously. The different colors represent Tado radiator TRV measurements in various rooms.
Both Tado and Remeha operate over OpenTherm and should theoretically work together. However, in practice, the performance is so poor that it undermines the benefits of having a combined system. I’ve consulted multiple central heating installation companies about this issue, and most have advised against using Tado with the Remeha Elga Ace—and even with most other brands of heat pumps that they were able to install. This is frustrating because I believe that with some software adjustments, it should be possible to call for heating in a different pattern.
Some users have suggested switching Tado to "on/off" mode instead of "modulation" mode to address this issue. Unfortunately, I haven’t been able to find any way to make this change through either the mobile app or web interface. I’ve contacted Tado support about this but haven’t received clear guidance on how to achieve it.
Additionally, the performance issue could be related to another concern. When I initially set up my Tado system (before the heat pump was installed), I recall inputting the brand and model of the gas boiler that the in the tado app. However, now that the thermostat is wired to the heat pump, I haven’t been able to update these settings. I contacted Tado support about this as well, the AI chatbot explained me that this setting change can't be done via the app and that I should contact support - but they haven't offered a solution so far.
Comments
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Update: I have got a more detailed response from Support. The reason why switching to On/Off mode isn't available via any app settings is that it requires rewiring of the thermostat and the heatpump.
(I assume swithing from the digital channel to a different) - Support warns that this is not officially supported, and not covered by warrenty.
That's a clear answer. (not the one I was wishing for though 🙂)
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Instead I have removed my tado thermostat, and installed the Remehas eTwist thermostat.
This instantaneously improved the heat pump situation.
Heat pump power use (W):
The gas boiler have only consumed 2m³ gas in this period. (including cooking + hot water)
Outdoor temperature (C ):
The heat pump is continously on when it is cold outside. Completely off when the indoor temperature meets target and is kept stable
Indoor temperature (C ):
Indoor temperature graph is much more stable, no high peaks, and follows defined target temperature better.
I hope this helps other who is considering combining tado with Remeha Elga ace hybrid heat pump.1
