Keep in mind that thermal storage is cheap compared to electrical, just not efficiently reversible. E.g. you heat up a block of paraffin in a tub of water and i

Keep in mind that thermal storage is cheap compared to electrical, just not efficiently reversible. E.g. you heat up a block of paraffin in a tub of water and it takes a lot of energy without large temperature changes due to the phase change. The output temperature would require rather large radiators or floor/wall heating. At this temperature you could even dump waste heat of a computer (well, CPU and GPU, maybe DRAM, not the rest) into this thermal storage.