Yes. In Germany they are selling a lot of models, but none, I mean, really, none asked about the rentability. So I went to a neighbour who just installed his 25kW and was very proud and happy, and asked him, in how many years is the return of investment. Siderated, he could not answer and then a few days later, with a very stern face: 25 years or more because if more people install these, the price that the city is paying for the pumped energy goes down.
So no. 20kw is not the answer. I showed my setup: 3.5kw + big battery. Pays the bill approx 60 70% of the daily usage. Investment payback : 5years.
What if he added previous generation crypto miner (so it's cheap) and use the excess electricity instead of selling it to the grid? This could also save some money on heating in winter unless he has a heat pump priced in already.
prev gen crypto mining is phenomenally inefficient in terms of energy that ends up being converted to heat, but it is absolutely not what you would use to take electricity and create heat given any other choices.
What are other choices? Heat pump is obviously the best but any other thing is just electric heater with 100% efficiently of heat generation. Pushing some bits around doesn't change that. I guess for some applications you might prefer higher temperatures but for residential heating crypto mining is as good as anything else, right?
25kW? That is crazy huge! How many panels? What does this guys house (mansion!?) look like? Google tells me that average installation size is about 7-8kW.
So no. 20kw is not the answer. I showed my setup: 3.5kw + big battery. Pays the bill approx 60 70% of the daily usage. Investment payback : 5years.