Battery. Electricity is more useful than steam.

Do the financials agree?

Sort of. https://shkspr.mobi/blog/2016/03/meet-maslow-the-uks-answer-...

Thanks for the writeup. I couldn't find a breakdown for the iboost but the Maslow was 2kwh for £2000.

Given that a water heater could absorb much more energy for less money, wouldn't that be the way to go, or at least go water heater first until you've achieved some maximum utility, then go for battery?

I think the iboost was under £100.

Sure the water can absorb more energy, but what can I do with it?