Heat pump + photovoltaic system with or without storage

We are planning a new building with an air heat pump. The electricity for it will come from our own photovoltaic system. Now the question arises whether a storage system makes sense or not? The house is 10 m wide and 14.5 m long. The main apartment is downstairs. The attic will be partially converted into a one-person apartment. Later, we plan to have an electric car. The installer has made us the following offer:

Heat pump Novelan 9-HSDV 12 Storage BYD Battery-Box Premium HVS 5.1 with FroniusSymo Hybrid 5.0-3-S 15 modules Trina Solar 340 TSM-DE06M.08; some of the modules on the east side, some on the west side (house is oriented north-south)

Is all of this reasonable? Does it fit together? Does anyone have experience with these brands?

Hi,.
Whether the heat pump fits depends on the heating demand of the house. Should it be the LAD 9 or LADV 9? It seems very generous in terms of capacity to me, which is not always good for efficient operation. The LAD does not modulate, so oversizing it would be a disaster. The LADV should be preferred then. However, at A7/35 it still has a minimum output of 2.74 kW. I can imagine that a smaller one would suffice. What does the heat load calculation say?
Storage for photovoltaics usually only pays off with Kfw 40 because then you reach KfW 40+ and the higher repayment grant then finances the storage. At least that was the case until 2019. A lot has changed, so you would have to inform yourselves again.
But if it is a KfW 40 house, the heat pump is definitely too big! (Or you’re building a palace)...

Cover the roof as much as possible, either fully with <=9.9 kWp or >12 kWp and omit the storage.

With the heat pump, make sure it fits and is not oversized; careful attention should be paid to this during planning.

Heidi, I also have a comparable system, with a battery LG ESS 12.8 kwh, have been living in the house since summer 2018. My advice: Do the photovoltaics on East + West, because then you have solar power from early in the morning until late in the evening when the sky is bright. Run the air-water heat pump only when there is photovoltaic yield, if possible. If you get a big subsidy for the battery – do it, about 10 kwh. If there is no subsidy and your financial reserves are rather limited: prepare the battery spacewise and with respect to the meter cabinet reserve, but retrofit it only in 5 to 10 years. Why? These things are still in the trial phase, quite lossy and above all very expensive. You won’t find electricity as expensive as the one from your own battery (without subsidy) anywhere in Germany, not even in the most expensive basic supplier tariff. If you buy an electric car soon anyway, you’ll already have a huge battery in the garage...

I have always complained about batteries as well - but now we have ordered our photovoltaic system with a battery after all. You have to calculate it precisely. Above all, the photovoltaic system should be large enough to fill, otherwise nothing will come in during winter. No one knows what will happen now with the Renewable Energy Act. In times of Corona, this is not a priority and it is becoming increasingly likely that no follow-up regulation will come into force before the cap falls, which would mean there would be no guaranteed remuneration anymore. Then only self-consumption (with battery) remains.

The note about retrofitting is correct. However, you can only get the VAT on the storage refunded when purchasing the system. Not when retrofitting.

Decisive for us were the dropped prices, the tax refund, and a funding program from the state. This makes the 11.2kWh effectively cost us only €4300. And we have (soon) almost 29kWp on the roof. The heat pump can also draw something in winter.

We also have an air-to-water heat pump with [Photovoltaik] and storage. I have linked my heat pump with the [Photovoltaik Manager], then it works great. 7.5 kWp on the roof, BYD HV 7.7 kWh in the basement. System in operation since Nov 19. The electricity from the storage now fully covers us during the transitional period because I heat my house and hot water during the day, so my heat pump does not run at night. Caution with subsidies: not every combination of [Photovoltaik]+ storage receives a subsidy. Not every combination can be deducted for tax purposes! With subsidies, there are often further restrictions, e.g., from 70% it is reduced to 50%!