[dpierce9]

The major thing that is unaddressed is the inertia of the extant built environment.

We know that lead paint is bad for people, especially kids, but we haven’t remediated it in much of the pre-1976 housing stock. Why? It is expensive and the places where it is worst are not high-value areas.

Similarly, there are many homes in America with low voltage knob and tube which is an uninsulated wire. Would you retrofit homes with a second DC circuit or use the existing AC infrastructure and be constrained by the choice of 12/14GA wire? Would new homes have two systems? Would you have a second set of DC distribution wires or a home inverter (with its own inefficiencies and failure modes)?

The supposed efficiency of DC for residential applications will be overwhelmed by the efficiency of doing nothing.

[zdragnar]

It's a tangent, but worth pointing out that like asbestos, lead paint remediation is often more dangerous than doing nothing. Paint over it, and it isn't hurting anyone. Sand it off, and now you have super fine lead particles floating in the air and settling all over the place just waiting to be disturbed and kicked up again.

Lead pipes are an entirely different matter, and remediation is usually (wrongly) deferred due to cost.

[dpierce9]

Lead remediation isn’t just sanding and covering with paint is not always a good idea. First windows and doors are painted friction surfaces which create lead dust. Second, painting over it assumes the bond between the substrate and the lead paint will hold in perpetuity. In practice it doesn’t but yes often painting is a good form of remediation. This does not work outside though. Third, sanding is not great for all of the reasons you mentioned but not the only way to remediate (e.g., steaming, chemical stripping, physical encapsulation, or removal are all options). Fourth, it was really just an example of how the built environment is incredibly sticky to things which are downright dangerous, known to be dangerous, and yet continue to persist because of the associated expense. Your example is also good.

[userbinator]

K&T is not uninsulated.

[sokoloff]

Can confirm. My previous house had some still in service for some general hallway lighting and other light loads. It was not jacketed (like modern non-metallic cable is), but it was definitely insulated.

[dpierce9]

I misspoke. The K&T I had in my house had gaps in the loom because it failed. You also can’t insulate around it.