I think this is cool, but I don't think the homeowner should have to pay up front for this datacenter in their home. I would be much more convinced to adopt this if I didn't have to pay for something that could be potentially loud, not work well, etc. For one thing, it just seems a bit scammy -- "Hey, just pay us to be our facility"! Also I don't think what the homeowner gets back from this system should be hinged on the usage of Nerdalize's services.
Lastly, what about electricity? I mean these things have gotta use a whole lot more electricity than a typical heater. All of which, I'm guessing, is again paid by the homeowner.
Leasing the computation equipment is a sensible way to bootstrap the process. There's risk associated with siting a computer at someone's home; if the homeowner has some money invested in the computer, they're less likely to walk off with it, repurpose it, or accidentally damage it.
If there's a developed home heating/computation market, homeowners would be happy to invest in a compuheater.
I think that a better way to hold homeowners responsible would be to charge them for damage rather than charge them for simply having it. It would probably convince more people to join in the first place.
This brings me to your second point -- the problem is precisely that there ISN'T a developed home heating/computation market, which is why it would be difficult to convince people to use it (considering they have no idea if it will work and what trouble it could cause them).
Lastly, what about electricity? I mean these things have gotta use a whole lot more electricity than a typical heater. All of which, I'm guessing, is again paid by the homeowner.