How to Prepare for a Long-Term Power Outage at Home

Most outages end within hours, and a flashlight and a cooler cover them. Outages that last days or weeks are a different problem: food spoils, sump pumps stop, wells go dry at the tap and pipes can freeze or basements can flood. Learning how to prepare for a long-term power outage means planning backup power for the few loads that really matter, storing enough water and food to ride out the gap, protecting the house itself and running any generator in a way that does not put your family or utility workers at risk.

Long outages come from ice storms, hurricanes, wildfires, heat waves and grid failures, so the plan should work in any season. Start with the essentials and add capacity as your budget allows.

How to Prepare for a Long-Term Power Outage: Start With a Load List

Before buying any backup power, list what you actually need to run and how much power each item uses. Check the nameplate sticker on each appliance for its watts, or volts and amps (watts = volts x amps). Motors such as refrigerators, sump pumps and well pumps need a short burst of extra starting watts, often two to three times their running watts.

Typical priorities, in order:

1. Medical equipment (oxygen concentrators, CPAP machines, refrigerated medication)
2. Sump pump, if your basement floods without it
3. Well pump, if you rely on a private well
4. Refrigerator and freezer
5. Furnace blower or boiler circulator for heat (the fuel may be gas or oil, but the controls and fans need electricity)
6. Lights, phone charging, a radio and internet equipment

Sizing Backup Power: A Worked Example

The general method is to add up the running watts of everything you want to run at once, then add the largest extra starting surge, because motors rarely all start at the same moment.

Here is an example using illustrative figures; your appliances will differ, so use their nameplates:

• Refrigerator: 700 running watts, 2,200 starting watts (1,500 extra surge)
• Sump pump: 1,000 running watts, 2,000 starting watts (1,000 extra surge)
• Furnace blower: 600 running watts
• Lights and electronics: 250 running watts

1. Total running watts: 700 + 1,000 + 600 + 250 = 2,550 W
2. Largest extra starting surge: 1,500 W (the refrigerator)
3. Peak demand: 2,550 + 1,500 = 4,050 W
4. Add about 20 percent headroom: roughly 4,900 W

In this example, a generator rated around 5,000 running watts would cover these loads. Well pumps, many of which run on 240 volts, and central air conditioners need far more capacity and usually require a hardwired connection.

Portable power stations and batteries

Battery power stations are rated in watt-hours (Wh) of storage and watts of output. They are quiet, produce no exhaust and can run indoors, which makes them ideal for medical devices, phones, lights, internet routers and short refrigerator runs. Divide the battery’s usable watt-hours by the load’s watts to estimate runtime. For example, a 1,000 Wh station powering a 50 W CPAP gives roughly 15 to 20 hours after conversion losses. A refrigerator that uses about 1.5 kWh per day would drain a 2,000 Wh station in a little over a day, so pair large batteries with solar panels or a generator for long outages.

Keeping the Sump Pump, Well Pump and Fridge Running

• Sump pump: a battery backup sump pump that kicks in when power fails is a strong first step. For extended outages, plan to run the primary pump from a generator. A water-powered backup pump is an option on some municipal water systems.
• Well pump: most need a generator connected through a transfer switch or interlock. Store extra water so you are not dependent on the pump at all for drinking.
• Refrigerator and freezer: keep them closed. A full freezer stays frozen for about two days, a half-full one about one day, and a refrigerator keeps food cold for about four hours unopened. Run the fridge a few hours at a time from a generator or station to keep temperatures safe, and use appliance thermometers to check.

Generator Safety: Outdoors, Away and Connected Properly

Portable generators produce carbon monoxide, an odorless gas that can kill within minutes. Follow these rules without exception:

• Run generators outdoors only, never in a garage, basement, shed, crawlspace or porch, even with doors open.
• Place the generator at least 20 feet from the house per general safety guidance, with the exhaust pointed away from windows, doors and vents.
• Install carbon monoxide alarms with battery backup on every level and near sleeping areas, and test them before storm season.
• Keep the generator dry, under an open canopy designed for that purpose, never on a wet surface.
• Turn it off and let it cool before refueling. Store fuel in approved containers away from living spaces and heat sources, and add fuel stabilizer for long-term storage.

Never backfeed

Plugging a generator into a wall outlet with a double-ended cord, often called backfeeding, can energize the utility lines and seriously injure or kill line workers and neighbors. It can also damage your wiring and start a fire. The safe ways to connect are heavy-duty, outdoor-rated extension cords sized for the load and run directly to appliances, or a transfer switch or interlock kit installed by a licensed electrician. Once a transfer switch is in place, you can power hardwired loads like a furnace or well pump safely.

Water and Food Storage

General preparedness guidance calls for at least 1 gallon of water per person per day for drinking and basic hygiene, and many households store two weeks’ worth for long outages. Add more for pets and hot weather. Fill bathtubs before a predicted storm for flushing toilets. Store water in food-grade containers in a cool, dark place and rotate it every six months or so.

Stock shelf-stable foods your household actually eats: canned meats and beans, peanut butter, crackers, cereal, dried fruit, nuts and ready-to-eat meals. Keep a manual can opener. If you plan to cook, use an outdoor grill or camp stove outdoors only, well away from the house, never inside or in a garage.

Protecting Pipes and the House

In winter, frozen pipes are a major risk. If the heat will be off for days and indoor temperatures will drop below freezing, either keep a heat source running for at least part of the house (a properly vented wood stove, or a furnace running on generator power through a transfer switch) or shut off the main water valve and drain the plumbing. Open faucets at the lowest and highest points of the house, flush toilets and consider having a plumber winterize the system if you leave.

In summer, the risks are heat and humidity. Know which room stays coolest, use battery fans and plan where vulnerable household members can go if indoor heat becomes dangerous. Keep the sump pump plan in place for storm-driven flooding.

Lighting, Communication and Battery Care

Use battery or rechargeable LED lanterns rather than candles. Keep a battery or crank weather radio, power banks for phones and a printed list of emergency contacts. Charge lithium batteries and power stations before storm season and keep them topped up. Follow the maker’s charging instructions, use the supplied or approved charger, keep batteries away from heat sources and flammable materials, and do not cover or bury them while charging. Stop using any battery that swells, smells or gets unusually hot.

Heating and Cooling Without Grid Power

Never use grills, camp stoves, outdoor propane heaters or generators indoors or in a garage for heat. A wood or pellet stove installed and vented to code is the most dependable non-electric heat; pellet stoves need power for their augers and fans, so plan a backup source. Unvented fuel heaters should be used indoors only if the label specifically allows it, with required ventilation. Any space heater must plug directly into a wall outlet or a generator cord sized for it, with 3 feet of clearance, and should never run while you sleep.

When to Call a Licensed Professional

Hire a licensed electrician to install transfer switches, interlocks, inlet boxes or standby generators, all of which typically require a permit. Standby generators fueled by natural gas or propane also need a licensed gas fitter for the fuel line. If you smell gas, leave the house and call your gas utility from outside. A plumber can winterize plumbing for a long absence, and an HVAC technician can confirm your furnace or boiler can run from generator power.

Costs in General Terms

Battery backup sump pumps and small portable power stations range from a few hundred dollars into the low thousands. Portable generators typically run from several hundred dollars to a few thousand depending on capacity and features, plus fuel storage. A transfer switch installed by an electrician adds a moderate cost, while whole-house standby generators cost significantly more installed. Weigh those costs against food loss, flooding and the length of outages in your area when deciding how to prepare for a long-term power outage.