Thanks for the feedback! Sorry I didn't see it until now.
People do install electric night storage heaters in existing housing, and this is just an especially cheap recipe for one. I don't think it would take much more space, although feolite and similar materials could cut the size by half. So it might be easier to do it before the house is built, but it shouldn't be necessary. Some wood floors wouldn't be strong enough to hold the weight, though.
I was proposing a daily thermal store, not a seasonal thermal store. A seasonal thermal store needs to be about a hundred times larger, which probably necessarily situates it outside the house. There does definitely exist housing that doesn't receive enough sunlight to compensate for its lack of insulation, especially in the winter.
People do install electric night storage heaters in existing housing, and this is just an especially cheap recipe for one. I don't think it would take much more space, although feolite and similar materials could cut the size by half. So it might be easier to do it before the house is built, but it shouldn't be necessary. Some wood floors wouldn't be strong enough to hold the weight, though.
I was proposing a daily thermal store, not a seasonal thermal store. A seasonal thermal store needs to be about a hundred times larger, which probably necessarily situates it outside the house. There does definitely exist housing that doesn't receive enough sunlight to compensate for its lack of insulation, especially in the winter.