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€45,000 for a heat pump retrofit in Germany -- really?
(www.bbc.co.uk)
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this post was submitted on 10 Dec 2023
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That pricetag is just the unit and standard installation probably. Pieces are crazy high Here in Germany because the demand is crazy high. Not many heating installers have made the additional qualifications, so those who did can demand practically anything.
It's not that the people don't want the technology, the adoption pace is just higher then the supply chains can deliver.
And btw: you don't need to reach 60°C with a heat pump. That would be pretty inefficient. That wouldn't prevent installers from up selling you, but that's a different story.
The issue is that the original radiators were sized to move the necessary n kW into the room with a water temperature of 60C. If you drop the water temperature to say 45-50C, you're only going to get roughly two-thirds of the heat transfer. The other third needs to be made up somewhere else - additional heating or better insulation.
As you said, running continously is the ideal point for heat pumps. And for a continous load most radiators are big enough. In Germany they were scaled so they could heat up the rooms pretty quickly and then idle for time. Since thats not the goal with a heatpump we can use the idle time to even out the lower peak capabilities. You loose the ability to quickly adapt the room temperture, but with outdoor temperature probes connected to the heatpump this istn an issue. I am in the process of retrofitting my home to a heatpump and that what the engineer told me at least.
A bigger issue seems to be the single-pipe heating vs. two-pipe heating systems, but those are not the majority in germany and should be phased out anyway because they are so inefficient.
Thanks for the feedback.
My boiler gives me control of the temp of the water running through the radiators which is independent of the room air temp thermostat. I set the water to ~55°C which seems to reasonably get the air to 17° without running continuously. I mentioned 60° because I figured that temp would enable someone to heat their room up quickly. I wonder why you say a heat pump would not need 60°. I would think the radiators need to reach a high temp like ~50—60° regardless of the kind of furnace. Maybe I’m doing something inefficient. Should I use a lower temp? I could lower the water temp but then there would be a point where the furnace has to run continuously which i would think is inefficient. I’m not sure how to find the efficiency sweet spot.
UPDATE
Sounds reasonable. So if the demand has out-stripped supply on heat pumps, I wonder if geo-thermal would actually be cheaper than a heat pump ATM. IIRC the digging would be ~€10k (what I think is a typical price for digging a well.. could be off). Though I don’t suppose you could use wall radiators with geothermal. Since geothermal water is only ~6° warmer in the winter, hydro-radiant flooring would have to be installed.
Running continuously is usually the ideal point. For heat pumps, it definitely is as the efficiency is highest with the lowest split between indoor and outdoor temps.
The issue is that if you suddenly want more heat, you first have to raise the water loop temperature before that can start pushing more heat into the house.
Systems are usually designed to keep up at perhaps 22-24C even on the worst days of winter; maintaining 17C is a lower target that can be met with less capacity and cooler radiators.