Photovoltaic system air-water heat pump - profitability single-family house KFW55EE

Hello,

we are building a fairly large KFW55EE house with external dimensions of about 10x14m and a roof pitch of 15° (roof surfaces facing north and south).
We have a lot of window areas (100m2) and expect an energy consumption of 7-9k kWh p.a. due to the size.
Heating is provided by underfloor heating with the air-to-water heat pump Tecalor THZ 504.

The feed-in tariff is no longer significant, but the electricity price is currently 45 ct/kWh.
We would have to finance the photovoltaic system as there is no sufficient budget left.

> From a profitability perspective alone, does a photovoltaic system make sense with our setup?
> What size and costs should we expect?
> Should it be installed directly or should preparatory measures via conduit pipes be taken first?
> We also have an attached 6x6m garage with a flat roof on the east. Does photovoltaic additionally make sense there?

Of course, I will still talk to companies but want to get opinions in advance.

Thank you very much in advance. :)

> From a profitability standpoint, does a photovoltaic system make sense in our situation?

A photovoltaic system from about +/- 10 kWp makes sense today even with the low feed-in tariff combined with self-consumption. You can easily calculate online what fits your roof and what yields to expect.

> What size and costs should one expect?

The bigger, the better. €1,100-1,200 per kWp net. If you have scaffolding on the house that the solar installers can also use, even better, because it’s cheaper.

> Directly on it or first prepare with empty conduits?

Directly on it.

We also have an attached 6x6m flat-roof garage on the east side. Does adding photovoltaics there make sense?

Get it calculated. It can make sense with regard to self-consumption.

We would have to finance the photovoltaic system since no sufficient budget is left.

Just take a €15,000 loan for a larger system. At max 1.5% interest and 4% repayment (you should check with KFW what exactly applies), that’s €825 per year. Revenue from feed-in tariff alone with an estimated 10,000 kWh generated power is €650 per year plus self-consumption of 2,000 kWh = savings cautiously estimated at €300 = the system will pay for itself after taxes all by itself. And that is a pretty conservative estimate.

Hello, we are building a fairly large KFW55EE house with external dimensions of about 10x14m and a roof pitch of 15° (roof surfaces facing north and south). We have many window areas (100m2) and expect energy consumption of 7-9k kWh p.a. due to the size. Heating is via underfloor heating with the Tecalor THZ 504 air-water heat pump. The feed-in tariff is no longer significant, but the electricity price is currently 45ct/kWh. We would have to finance the photovoltaic system ourselves since there is no sufficient budget available anymore. > From a profitability point of view, does a photovoltaic system make sense with our setup? > What size and costs should be expected? > Directly installed or first take preparatory measures with empty conduits? > We also have an attached 6x6m garage with a flat roof in the east. Does photovoltaic make sense there in addition? I will of course still talk to companies, but would like to get some opinions in advance. Many thanks in advance. :)

It definitely makes sense. Do you have air conditioning installed in the house? Because then it would make even more sense, since when you want to cool, the most electricity is produced. What about a wallbox?

Thank you for the answers, sounds good. Climate control no, ventilation yes. Wallbox in the garage should also be installed, hopefully the KfW subsidy will return. But I can charge for free at work. Bidirectional would be nice, then I would have a 60+kwh battery, but the boxes are still way too expensive. ;)

Thanks for the answers, sounds good.
No air conditioning, yes ventilation. A wallbox is also to be installed in the garage, hopefully the KfW subsidy will come back. But I can charge for free at work.
Bidirectional would be nice, then I would have a 60+kwh battery, but the boxes are still way too expensive. ;)

The topic of bidirectional charging is just the question. If your battery is empty every day and you have to charge it every day, how long will it last? I was also excited about something like that until I was enlightened.

Legitimate question. Due to my profession, I change vehicles every few months, so there should not be significant impacts per vehicle. It is also questionable whether, in such cases, for example, the 6-10 year battery warranties from the manufacturers apply (in case of over 25% capacity loss) or if this is excluded due to maximum charging cycles.