Actually tolerating staying inside your bunker on a minimum of energy.
Let's assume you have a bunker that's 6 ft x 20 ft x 5 feet high underground. Let's further assume that it's hidden and only you and your family know about it. What would be your plans for light, ventilation, electricity and communication, all without being detected? How long would you plan on staying hidden? How would you cook? Let's assume water and waste are taken care of (hand pump for well in bunker, sewer attached to bunker.