The requirements to build it on new homes makes old homes more valuable because they have one less requirement. It makes already built homes relatively more valuable to new ones.
This doesn't make sense. When you add an asset to one thing it doesn't mean that things without that asset go up in value. Are buyers like "oh you have a house with no solar pannels?! I want to pay more for that!"?
You're suggesting that a house with solar panels pre-existing is a net burden on homeowners? I can't imagine that as a serious contention but I installed solar and every option had excellent warranty coverage that spanned owners, and the energy offset alone for an already installed system is an annuity worth thousands of dollars.
