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

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. 🙂

Deliverer14 Jan 2022 15:43

#55

I always recommend using the Christmas holidays as a reference: The whole (vaccinated) family is visiting, ALL the lights are on, the goose has been in the oven for five hours, and the next day you need 200 km (125 miles) of driving range in the car.
Oh, and of course, it rains nonstop. Typical Christmas. ;-)

WilderSueden14 Jan 2022 15:53

#56

Oh man, I really started a discussion here. I’ll make sure not to invite the family so that the photovoltaic system is sufficient 😉

Deliverer schrieb:

the next day you need 200 km range in the car.

For us, the trip to the Christmas holiday is 280 km (175 miles), with the possibility of having to wait for the car shuttle at the Furka Pass in cold weather.
So far, no problem at all—50 liters (13 gallons) of diesel is enough to get there, back, and around without relying on photovoltaics 😉

tomtom7914 Jan 2022 16:33

#57

When the house is fully heated from cooking, you can turn down the heating :^)

I’m curious to see what Habeck has planned in the Easter package. There are plenty of speculations.

Maxwell823 Jan 2022 20:10

#58

Is it still worthwhile nowadays to have two meters, or should everything run through just one?

Currently, our heat electricity rates are 32ct/kWh, while regular electricity rates are 45ct/kWh.

With our consumption, that quickly amounts to a difference of over 1000€ per year.

WilderSueden23 Jan 2022 20:15

#59

Do you even have a choice? In most grids, the utility company now requires two meters, regardless of whether it makes sense for you.
With a difference of 1000€ (about 1100 USD), I would definitely go for two meters.

tomtom7923 Jan 2022 20:22

#60

Those are very high prices. Has the contract just been signed? Otherwise, I would try to switch.

Apart from that, it is also possible to feed electricity into the grid with a photovoltaic system using two meters. This is called cascade metering or something similar.

ᐅ Photovoltaic System and Air-to-Water Heat Pump – Profitability for a Single-Family Home Built to KfW 55 Energy Efficiency Standard

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