How long it really lasts

Most outages are short. The average US customer was without power about five and a half hours in all of 2022 (EIA). The ones worth planning for are the big winter events:

  • Texas, February 2021. Millions of people were without heat or power for nearly four days, and the grid operator cut load for three straight days (FERC/NERC). The state counted 246 deaths, 158 of them from hypothermia (Texas DSHS).
  • Kentucky ice storm, January 2009. About 770,000 customers lost power, and most of Louisville was dark for 10 to 14 days (Kentucky PSC, Kentucky Living).
  • The 1998 ice storm in New York, New England, Quebec and Ontario. About four million customers lost power, some for weeks and a few for about a month (National Weather Service).

So a sensible plan covers about four days, and two weeks if you live where ice storms happen. The grid regulator still rates much of North America at elevated risk of shortfalls in a long, wide cold snap (NERC).

What stops working, and when

  • Heat, within the hour. A gas furnace needs electricity for its blower and igniter. No power, no heat, even with a full gas line.
  • Water, right away on a well. A well pump needs power, so no power means no water.
  • The fridge, after about 4 hours. A full freezer holds about 48 hours if you keep it shut, 24 if it's half full (USDA).
  • Phones and internet, within hours to days. Many cell sites carry only hours of battery; some have generators (FCC). Your router dies with the power.
  • Medical devices, like a CPAP or oxygen concentrator, as soon as their battery runs out.

What you'd need

Power for the few things that matter. In a winter outage, that's the furnace fan, the fridge, the well pump if you have one, lights, phones and any medical device. That's a small, steady load, which is exactly what batteries do well. Your setup's numbers are above; the sizes come from the guides.

A safe way to heat if that fails. One room, closed off, with blankets over the windows and everyone sleeping there. Never heat with a gas oven or stove (Ready.gov).

Water: at least a gallon per person per day (Ready.gov).

Food that needs no cooking, or a way to cook outdoors.

Carbon monoxide detectors with battery backup on every level (Ready.gov). This one matters most if anyone in the house will run a generator.

The catch with generators

Generators work, and lots of people rely on them. Two things go wrong:

  • Carbon monoxide. Portable generators kill about 100 Americans a year, mostly from November to February during storm outages (CPSC). Keep it outside, at least 20 feet from windows, doors and the garage (Ready.gov).
  • Backfeeding. Plugging a generator into a wall outlet can push power back into the lines and kill the crews restoring them (ESFI). Use extension cords, or have an electrician fit a transfer switch or interlock.

Fuel is the quiet third problem: in a long outage, gas stations need power to pump too.

Batteries charged by solar avoid all three. They're silent, can sit indoors, and refill themselves on any day with sun. The trade-off is up-front cost and the days right after the storm, when snow or ice covers the panels. That's why the run above starts with two dark days.