Hello RotorMotor,
now we have found a good basis for discussion and I am happy to answer all your questions (I am addressing you informally because that is common in forums; if you do not want this, please let me know briefly – no problem).
1. If we only compare heating systems with each other, this comparison is very flawed because the heat pump naturally has a COP that is higher than that of IR heating systems. The comparison would end quickly because the heat pump is obviously better. There is consensus on this. I also agree that if money is no object for the building family and they want to supply themselves almost completely independently, a system with a ground source heat pump plus a large photovoltaic system and a large battery is a great system – just very expensive. Hence the full cost calculation (by the way calculated according to VDI 2067. The VDI 2067 guideline series deals with the calculation of the economic efficiency of building-related technical systems. It applies to all types of buildings). We assume the same budget and compare what results for the building family in the end. We present the most economical system for the building family – and that is precisely a direct electric heating system in combination with photovoltaic and battery. This is actually the task of energy consultants, who are paid by the customer to present them with the best, most economical, or at least different systems. But often the heat pump is simply taken and that’s it. I want to give the energy consultants the benefit of the doubt that they often just don’t know better.
2. Financing is usually always credit-based anyway – whether heat pump or direct electric heating with photovoltaic + battery. So both conditions are equal again.
3. A hot water heat pump from LG costs approx. 2,000 € including delivery to the curbside. Plug into the socket, connect two water pipes beforehand – done. Anyone charging more than 5,000 € for this is ripping off the customer – but unfortunately that is currently not uncommon. :mad:
4. U-value
The U-value of your floor is therefore 0.15 W/m²K. The U-value of our heating glass is 0.5 W/m²K.
Let’s calculate the losses for both components: 150 m² x 0.15 W/m²K x 12 K (delta T room temperature against earth – we neglect the higher heat transfer to the earth here) -> 270 W losses to the earth.
And now the glass: 20 m² (approx. 13% of the living area) x 0.5 W/m²K x 16 K (delta T room temperature against outside air – we also neglect the lower heat transfer to air here) -> 160 W losses to outside air.
So actually more energy is lost to the earth than through the glass. Did you expect that?
5. Figures, data, facts
On our homepage, you will find the technical data sheet for the heating glasses with the important glass technical data:
U-value: typically 0.5 W/m²K
Light transmission: mathematically slightly lower – optically not noticeable
g-value: on the same level as normal triple insulating glass
Efficiency: This was measured in a test room at the Hermann-Rietschel-Institut at TU Berlin.
By the way, now with two different measuring methods. The first time it was 92%, and recently, through an external commission within the framework of a study (comparison of heating systems) of ISFH Hameln in cooperation with the Forschungszentrum Jülich with an improved measuring method, an efficiency of 95%.
I hope I have answered your questions satisfactorily so far and look forward to further questions.
At this point, a reminder – if you want to invest the 90 minutes – take a look at the webinar on our homepage.
There are 45 minutes of presentation and 45 minutes of questions from energy consultants.
Best regards
Andreas