Switching from gas to solar / photovoltaic with / without heat pump

Hello everyone,

we have a semi-detached house and renovated it completely in 2014. Underfloor heating, new pipes, electrical system, etc. were installed. Only the "old" gas heating system was not replaced.
Climate change, rising energy prices (you all know the reasons very well yourself) are motivating us to replace the heating system.

What is important to us?
- More independent from gas & electricity
- Subsidy through a loan

[*]What is currently "state-of-the-art" and what is installed here?
[*]Solar and/or photovoltaic with/without heat pump?
[*]With/without electricity storage?

Unfortunately, I do not yet have an overview of what would be good for us.

I hope you can help me get started on which direction to take.

I haven't had this combination for long, but based on my very low consumption values, I suspect it is quite good ;)

[Solewasserwärmepumpe + Photovoltaik + Batteriespeicher]

My layman's recommendation (based only on my own experiences!):

- Photovoltaics as large as possible (roof fully utilized, gladly up to 30KWp)

- Dimension the battery storage depending on consumption* (*in summer between 6:00 PM and 8:00 AM).
If you can bridge this period with it, the charge cycles remain reasonable and you optimize self-consumption

- Heat pump: We have an AI brine-water heat pump to achieve high efficiency and "passive cooling." But there are experts who can say more about this.
Unfortunately, I do not know what is currently subsidized, but I suspect that in the future, especially building modernization will have to be massively subsidized

I would also rely on photovoltaics + heat pump. Whereas ground-source heat pumps are significantly more expensive and therefore more suitable for larger houses, air-to-water heat pumps usually require an outdoor unit and are not quite as efficient. Which, however, does not weigh that much for a house at today's state of the art.

I currently consider battery storage still too expensive. However, if electricity prices remain that high - which I don't believe - the pendulum will increasingly swing in favor of storage.

If the power storage is your future electric car, with directional charging capability, all the better. I would also consider a heat pump with a large photovoltaic system as a favorite. I hope the underfloor heating is designed for 30 degrees, because it has already been renovated.

The question with the storage is what is meant by "high electricity prices." I still have 40c/kWh from storage as a rule of thumb in mind (is that still valid?). With that, one currently has price parity with cheap new contracts. I consider it rather unlikely that we will return to 30c/kWh in the next 2-5 years. Accordingly, the risk of paying significantly more for storage is limited. Apart from the fact that electricity is currently not only largely generated from Russian gas but also from Russian hard coal. An expansion of wind and photovoltaics will certainly reduce this share but will require expensive storage at the grid level for controllability.

Semi-detached house, renovation 2014 sounds like quite a manageable heating energy demand. How much gas do you need per year? With that number, you can roughly estimate the heat pump capacity.

Solar thermal never pays off. Therefore, roof full of photovoltaics. Also east, west, north up to 25° slope, garages, carports, south facade... The more, the better, cheaper, and more climate-friendly. Storage makes sense from about 60 cents electricity price. So it really depends on your crystal ball whether you want to do that. With a heat pump, I would only add storage once you exceed 20 kWp. If the photovoltaics are smaller, the heat pump otherwise leaves nothing left for the storage. An electric car worsens the storage balance again because it then virtually sees no kWh from October to February...

I can't think of any funding via loan (KfW). But from Bafa, there is a 35-40% subsidy on heating replacement heat pump against gas including everything.