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. 🙂

opalau13 Jan 2022 14:38

#25

Weather forecast for Pforzheim with sun icons and times

No wonder you can reach 10 kWh even in January.

tomtom7913 Jan 2022 14:43

#26

I was even outside in a T-shirt :-) but for me, it definitely helps to understand how much energy the sun produces.

Mahri2313 Jan 2022 14:47

#27

We don’t expect more than 5 hours of sunshine again until January 18th. 🙄

Deliverer13 Jan 2022 19:08

#28

To illustrate the differences:

Probably the saddest day in the life of the system:

Consumption and generation chart: red consumption, green self-supply.

And no – nothing was broken.

And the best January day so far:

Daily consumption and generation chart showing consumption, self-consumption, and feed-in.

OWLer13 Jan 2022 19:42

#29

Since I don’t see any extreme peaks, the question is where is all the electricity going? I recently barely reached 80 kWh in a day during cold temperatures, but that was because I charged the car twice.

0.7 kWh is really very low compared to January 12th. What self-sufficiency rate have you achieved so far in January? With my 10 kWp east/west system, I have managed a decent 6%.

Deliverer13 Jan 2022 20:39

#30

My house has a heating load of about 9 kW at the current temperatures (~-4°C (25°F)). Most of the electricity consumption comes from heating. The power drops are all defrosting cycles, which also shows how humid the air is. Then there are two hours of electric car charging (3.6 kW), two laundry loads, one dryer cycle, and one dishwasher run. The base load is about 300 watts.

And yes – the fourth event was truly unlike anything we’ve seen before. It felt like night all day… November and December didn’t have a single day under 4 kWh. And then this happened…

I’ve actually never looked into the self-sufficiency rate, but I found it for January:

Bilanz: Verbrauch 715,21 kWh; Ertrag 393,02 kWh; Eigenverbrauch 201,11 kWh

During the summer months, it’s over 70%; November and December are around 30%.
28 kWp system, no battery storage.

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

Reaktionen