In all fairness, low efficiency heaters and a/c need to be phased out, replaced with a much more cost effective technology, called thin sheet aerogel.
Aerogel is amazing stuff, first invented in 1931. Until just the last few years it was the lightest known solid material. Unfortunately, it was both very expensive and brittle. But why does it matter?
Because aerogel is a ridiculously efficient heat insulator, for both cold and heat. If you lined a sleeping bag with a 3mm layer of aerogel, you could sleep out in the open during a blizzard in the Arctic, at least until you couldn’t stand the sauna like heat inside your sleeping bag any more.
But for years it was just an oddity, because, as I said, it was both expensive and brittle. Until about a decade ago, when somebody created far less expensive, flexible, thin sheet aerogel.
They are now putting thin sheet aerogel into mass production. NASA wants to use it to insulate space probes from the cold of space. Otherwise the potential demand is huge.
If you insulated your oven or refrigerator with it, it would use far less energy. If you insulated your house with it, you could probably heat your house with an illegal 100W bulb and body heat, in the dead of winter. In the desert southwest in summer, you could air condition your entire house with window air conditioner.
For now, thin sheet aerogel is still expensive, but things change. And if you can save hundreds or thousands of dollars every year from heating and cooling, why not?
Regardless of new technology.. who are you to say when someone has to replace their furnace?