Lots of people have had this idea since the early days of Bitcoin mining. Some have even done it. I recommend looking up how people have set up mining rigs in their homes.
I’d imagine it’s a bit easier with Bitcoin, as the mining rig would belong to the home owner.
It comes vastly more complex when a company is looking to rent a portion of a person’s basement. They’d probably want to have levels of physical security, then access for any required service. Power usage would need to be tracked and accounted for—-who pays it? I’d imagine there would also need to be a common interface for collecting and making use of the heat, if it isn’t just a generic space heater.
I’ve also wondered if some kind of Folding@home project would work for distributing training or load of an open-source model that isn’t owned by a megacorp.