ᐅ Photovoltaic System and Air-to-Water Heat Pump – Profitability for a Single-Family Home Built to KfW 55 Energy Efficiency Standard
Created on: 11 Jan 2022 23:19
M
Maxwell8
Hello,
we are building a fairly large KFW55EE house with external dimensions of approximately 10x14m (33x46 feet) and a roof pitch of 15° (roof surfaces facing north and south).
We have a lot of window area (100m2 (1,076 sq ft)) and expect an energy consumption of about 7-9k kWh per year due to the size.
Heating is provided by underfloor heating with the Tecalor THZ 504 air-to-water heat pump.
Feed-in tariffs are no longer significant, but the electricity price is currently 45 cents/kWh.
We would have to finance the photovoltaic system ourselves because there is no sufficient budget left.
> From a profitability perspective, does a photovoltaic system make sense in our situation?
> What size and costs should we expect?
> Should it be installed directly or should we first prepare with conduits?
> We also have an attached 6x6m (20x20 feet) flat-roof garage on the east side. Would adding photovoltaic panels there be beneficial?
I will, of course, speak with companies but would like to gather some opinions beforehand.
Thank you in advance. 🙂
we are building a fairly large KFW55EE house with external dimensions of approximately 10x14m (33x46 feet) and a roof pitch of 15° (roof surfaces facing north and south).
We have a lot of window area (100m2 (1,076 sq ft)) and expect an energy consumption of about 7-9k kWh per year due to the size.
Heating is provided by underfloor heating with the Tecalor THZ 504 air-to-water heat pump.
Feed-in tariffs are no longer significant, but the electricity price is currently 45 cents/kWh.
We would have to finance the photovoltaic system ourselves because there is no sufficient budget left.
> From a profitability perspective, does a photovoltaic system make sense in our situation?
> What size and costs should we expect?
> Should it be installed directly or should we first prepare with conduits?
> We also have an attached 6x6m (20x20 feet) flat-roof garage on the east side. Would adding photovoltaic panels there be beneficial?
I will, of course, speak with companies but would like to gather some opinions beforehand.
Thank you in advance. 🙂
Thank you for the many responses.
Photovoltaics weren’t included in this calculation, of course. That reduces the amounts significantly.
According to the preliminary energy calculations, we are looking at just under 35 kWh per sqm (square meter) per year. With 270 sqm (square meters) of usable floor area and 235 sqm (square meters) of living space (no basement), as well as an open construction style, that means approximately 9000–10,000 kWh consumption for the heat pump. I’m curious to see what the actual consumption measurement will show.
Deliverer schrieb:
Something doesn’t add up. A €1000 difference corresponds to 7700 kWh from the grid alone. With the current heat pump, that’s 30,000 kWh of heat. Before worrying about the meters, I would have a plumber take a look.
Generally, nowadays it usually doesn’t make sense to install a second meter in new builds (due to the additional basic charge). As the share of renewable energy increases, the price difference between heat pump electricity and regular electricity will also decrease, so it won’t be worthwhile for anyone in the future.
You also have to consider that if the heating system is not allowed to run for about four hours a day, you need to size it larger—about one sixth bigger. If there is no more suitable option anyway, that’s fine. But if I have to get the next bigger model just because of the second meter, I would rather skip that.
Photovoltaics weren’t included in this calculation, of course. That reduces the amounts significantly.
According to the preliminary energy calculations, we are looking at just under 35 kWh per sqm (square meter) per year. With 270 sqm (square meters) of usable floor area and 235 sqm (square meters) of living space (no basement), as well as an open construction style, that means approximately 9000–10,000 kWh consumption for the heat pump. I’m curious to see what the actual consumption measurement will show.
R
RotorMotor23 Jan 2022 21:13WilderSueden schrieb:
The grid operator. In my case, it is Netze BW (EnBW), while for you it is probably someone else 😉
This is stated in the connection conditions, and the electrician installing the meters must comply with it.I was not able to find any indication from Netze BW that a second meter is required. Rather, it only says that a disconnecting device is needed if you want to use a specific tariff?!Could you please specify again where this regulation is stated?
Such a requirement would be very surprising given the power consumption of a heat pump.
W
WilderSueden23 Jan 2022 21:18RotorMotor schrieb:
Could you please tell me again where this regulation is stated? As I said, I can’t find it anymore. At least nothing I clearly understand. Maybe it has been removed again, I don’t know. In any case, I will also ask the electrician because I don’t consider the second meter reasonable given the expected consumption.
RotorMotor schrieb:
Such a requirement would be very surprising given the power consumption of a heat pump. Not really. On the one hand, it’s not that low, and on the other hand, it runs a lot. And then the quantity makes the difference. Peak load is expensive.
R
RotorMotor23 Jan 2022 21:25WilderSueden schrieb:
Not really. On one hand, it’s not that little, and on the other, it runs a lot. And then the mass makes the difference. Peak load is expensive. At least in their document regarding EV charging stations, it states that they are allowed to continue charging at 5.5 kW (7.4 hp) even when locked.
A heat pump in a new build usually draws a maximum of around 1 kW (1.3 hp).
D
Deliverer23 Jan 2022 22:38Maxwell8 schrieb:
According to the preliminary energy calculations, we are at just under 35 kWh per square meter per year. That means, for 270 m² (2900 sq ft) of usable area or 235 m² (2530 sq ft) of living space (no basement) and the open design, about 9,000–10,000 kWh consumption for the heat pump. You still need to divide that by four, then you have the electricity consumption.
Just sayin'...
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