A wise move to consider power alternatives for winter. Mobile battery packs do help in a pinch, but for extended outages, you might want to consider a portable generator. Remember though, indoor usage can be deadly due to carbon monoxide buildup, so you'd need a well-ventilated outdoor place for it. As for heat retention, BlueHarborTea's absolutely right about thermal undergarments. Layering is essential! Also, those reflective emergency blankets can be real lifesavers. They trap up to 90% of your body heat and are super lightweight too, great for your emergency kits. Anyone thought about candle heaters? They're small, DIY projects that can provide a bit of warmth. Just be cautious with open flames, of course. It feels a bit like pulling survival tips from my favourite post-apocalyptic novels, doesn't it? Have