Next step is getting rid of all those led bulbs in your house and using candles in the evening.
Discussion
LED manufacture has a multi-continental supply chain, which may not always be there when we need it.
Candles and oil lamps have truly rubbish efficiency, but store well and can be DIYed.
Incandescent has much better (but still lousy) efficiency with a short supply chain and widely proliferated tech.
Gas discharge and microwave-sulphur-plasma can almost compete with LED on efficiency, and with incandescent on supply chain length. But don't scale very small.
Cathodoluminescence, now that I need to experiment with :p
I have to add that candles are useful for some limited heating purposes. Yes i know it sounds odd, but there can be a difference. A candle lantern (like the big from uco for example) can produce up to 5000 btu.
Yeah, but two candles uses as much oxygen as a person.
Can't be having that in your secret underground lair.
An underground lair has stable temperature, doesn't need heating really 😀
True, but some might need it for dehumidification, depending on local climate and geology.
Not every underground doomer/villain lair can be built into a salt dome under Mount Olympus :)
Yes humidity might indeed be an issue. But it is ok then for aging your wine 😀
Need? No. But I certainly do *prefer* a temperature above 16°C.
It's nice after coming in from a hot day on the surface in the summer, but in the winter it doesn't exactly feel "warm". 🤣