Is a photovoltaic system also sensible in the West or East?

Highest efficiency is usually expensive and the economic efficiency eventually suffers. The sweet spot is currently around 330Wp/standard module or slightly below. The manufacturer is relatively irrelevant when it comes to efficiency.

Of course, there are other quality features. I had the solar installer offer me his three common modules and then looked at which one I liked best. It was the one with the low price per [Wärmepumpe].

Yes, sounds good. Besides the heat pump specification per module, what were your other factors that influenced your decision?

Are there also color differences? Blue-black, gray or something like that? I have the impression that there are differences.

On pitched roofs, the appearance certainly plays a role. Otherwise, there are also people who prefer long warranties and are willing to spend money on them (sometimes disproportionately).

We only requested quotes for black modules. They are either somewhat more expensive or have less performance.

Furthermore, we decided based on price and then on whether they were from a reputable manufacturer. The price differences were too significant for the decision to be difficult. There are modules with and without toxic metals, in case that is still important to you. Ours also had slightly better properties in shade (Duo/6 sub-areas), but these are marginal differences and were not a decision criterion. All had long warranties.

The expensive ones were super sturdy or had very high performance per area but would not have been economically viable.

All nonsense as long as there is no new government funding. Payback period is too long and capital commitment too high.

Everything is nonsense as long as there is no new government subsidy. Payback period is too long and capital commitment too high.

Hopefully it won't come anymore. Photovoltaics are marketable and no longer need subsidies.