mid-1800s in new england checking in. No knob in tube here, but guilty as charged on the sagging floors.
I've also DIY installed 3 mini split units in the house -- the last one being an AC / DC unit that directly gets powered via 4 panels on the roof during the sunny moments of the day.
Built a new addition 3-4 years back. It's far better insulated than the main structure, but the wood stove and heat pump combo keeps winter mostly at bay.
Anything over 30 years is insane.