Power Outage Preparation: What to Do Before, During, and After

In April 2025, the Iberian Peninsula went dark. Not for an hour. Not for an afternoon. Millions were without power for hours — some for over a day. And in the chaos that followed, the pattern was the same one I have seen after every major outage in my career: the people who had a plan — even a basic one — were frustrated but fine. The people who did not were scrambling.

The thing that surprised nobody in the trade? The surge when power came back on destroyed more electronics than the outage itself. Refrigerator control boards. Router power supplies. Furnace circuit boards. Thousands of dollars in damage from a two-second voltage spike at restoration.

Here is the plan I give to clients, organized into three phases: what to do now (before an outage), what to do when the lights go out (during), and what to do the moment power returns (after). None of this is complicated. Most of it costs nothing.

Before: The Pre-Outage Checklist

You cannot predict when the grid will fail, but you can predict that it will fail eventually. Do these things once, and they are done until you need them.

Know your utility’s outage map

Every major utility has a web-based outage map. Find yours and bookmark it on your phone — not your desktop, because your desktop will be off during the outage. These maps show the affected area, estimated restoration time, and crew status. They are far more useful than calling the utility and waiting on hold behind ten thousand other people.

Search “[your utility name] outage map” and save the URL. Do it now.

Freeze water bottles

Fill empty plastic water bottles two-thirds full (water expands when it freezes) and keep them in your freezer. They serve two purposes during an outage: they act as thermal mass to keep the freezer cold longer, and when they eventually thaw, you have drinking water. If your freezer is not full, pack the empty space with these bottles. A dense, frozen mass holds temperature far longer than air.

Surge-protect everything — seriously

The restoration surge is not hypothetical. When power returns to your neighborhood, every motor, compressor, and power supply in your house tries to start simultaneously. The resulting voltage spike and harmonic distortion can and does kill sensitive electronics.

At minimum, every expensive electronic device should be behind a quality surge protector — and if you are still using the $8 power strip from the drugstore, replace it with one that has an actual UL 1449 listing and a joule rating you can verify. Better yet, install a whole-house surge protector at your electrical panel. It clamps the big surge where it enters the house, before it ever reaches your devices. See the whole-house surge protector installation guide for a complete walkthrough.

Build a basic outage kit

This does not need to be elaborate. A plastic storage bin with these items covers 90% of outage scenarios:

• Flashlight or headlamp with fresh batteries (not your phone — you will drain the phone battery using it as a flashlight)
• Battery-powered lantern for room lighting (more useful than a flashlight for cooking or reading)
• Portable phone charger / power bank, fully charged (a 20,000 mAh bank charges a phone 4-5 times)
• Battery-powered or hand-crank weather radio (your phone’s data may drop when cell towers lose backup power)
• First aid kit
• Three days of non-perishable food that does not require cooking
• One gallon of water per person per day, for three days
• Manual can opener
• Cooler and ice packs (for consolidating critical fridge items when the outage drags on)

Document your devices’ wattages

If you plan to use backup power, write down the running and starting wattages of your critical appliances before the outage. The label on the device or its manual has this information. Tape the list to your generator or power station. When the power is out and it is dark and you are tired, you will not remember whether the refrigerator draws 700 watts or 1,200.

For a full comparison of backup power options, read Portable Power Station vs Generator. If you are considering a permanent installation, the home standby generator cost guide covers the real numbers.

Medical equipment: have a written plan

If anyone in your household relies on powered medical equipment, this is not optional. Register with your utility’s medical baseline program — this flags your address for priority restoration. Have backup power sized correctly for the device’s wattage. Know which nearby hospital or care facility has backup power and how to get there. Write all of this down and keep it with the equipment. In a crisis, memory fails — a written plan does not.

During: What to Do When the Lights Go Out

Step 1: Confirm it is not just you

Check your breaker panel. If no breakers are tripped, look outside — are the streetlights off? Are your neighbors’ houses dark? If it is just your house, the problem is between the utility transformer and your panel, and you should call your utility. If the whole block is dark, it is a grid outage — proceed to the next steps.

Step 2: Unplug sensitive electronics

TVs, computers, gaming consoles, stereo receivers, smart home hubs, and anything with a microprocessor. Unplug them from the wall. The restoration surge does not care whether the device is turned off — the spike travels through the power cord regardless.

Leave one lamp switched on (plugged in) so you have an immediate visual signal when power returns. A lamp you can see from where you will be waiting.

Step 3: Do not open the refrigerator or freezer

Every time you open the door, you trade hours of cold for seconds of looking. A full freezer stays below freezing for about 48 hours with the door shut. A half-full freezer: about 24 hours. A refrigerator stays below 40°F for about 4 hours.

If you have a cooler and ice packs, consolidate the most perishable items — milk, meat, medications that require refrigeration — into the cooler and keep it closed. Put a refrigerator thermometer in there so you can check temperature without opening the door repeatedly.

Step 4: Manage your phone battery

Your phone is your lifeline for outage updates, emergency calls, and information. Switch it to low-power mode immediately. Turn off Bluetooth, background app refresh, and any non-essential services. If you have a power bank, connect it now, not when your phone hits 5%.

Cell towers typically have 4-8 hours of backup battery. After that, data service may drop. SMS messages use far less bandwidth and may get through when data fails. If you need to reach someone, text rather than call — it uses less battery on both ends and is more likely to connect on a congested network.

Step 5: Generator safety — this is not optional

If you are using a portable generator, read this paragraph twice: carbon monoxide kills more people during power outages than the power outage itself. Every year.

Run the generator outdoors, at least 20 feet from any door, window, garage opening, or vent. Not in the garage — even with the door open. Not on the porch. Not under an overhang. Carbon monoxide is odorless, colorless, and accumulates in enclosed spaces. You will not know it is there until you are too disoriented to do anything about it.

Install battery-powered CO detectors on every level of your home, including near sleeping areas. Test them before outage season. The plug-in CO detectors do not help you — they need utility power.

Never refuel a hot generator. Gasoline spilled on a hot exhaust ignites instantly. Turn the generator off, wait 15 minutes for it to cool, then refuel on a non-flammable surface well away from the generator.

For generator connection options — extension cords vs transfer switch — see the Generator Transfer Switch Guide.

Step 6: Stay warm (or cool) safely

Winter outages: Layer clothing. Wear a hat — you lose a significant amount of body heat through your head. Use sleeping bags rated for cold weather. Close off unused rooms and focus on keeping one room habitable. If using a portable propane heater rated for indoor use, crack a window for ventilation and keep a CO detector in the same room. Never use a gas oven, charcoal grill, or outdoor propane heater indoors — all produce lethal amounts of CO.

Let faucets drip slowly to prevent pipes from freezing. If the outage is prolonged and the house will drop below freezing, shut off the main water valve, open all faucets, and drain the system. A burst pipe does far more damage than a few hours without running water.

Summer outages: Stay on the lowest floor of the house — heat rises. Close blinds and curtains on sun-facing windows. Hydrate continuously — drink water before you feel thirsty. Avoid heavy meals and alcohol, both of which increase dehydration. If the temperature becomes dangerous (above 95°F indoors for extended periods), find a cooling center — most municipalities open them during extended summer outages. Call your local non-emergency line or check the utility’s website for locations.

After: The Moment Power Returns

Step 1: Wait before plugging everything back in

Power restoration is often unstable for the first few minutes. The utility may cycle power on and off as they bring segments of the grid back online. Wait 10-15 minutes after the lights come back on and stay on before plugging anything back in. This avoids subjecting your electronics to a sequence of surges and sags as the grid stabilizes.

Step 2: Reconnect gradually

Do not flip every breaker and power strip on simultaneously. The cumulative inrush from every device starting at once can trip your main breaker or cause a localized voltage sag. Reconnect devices in this order:

1. Refrigerator and freezer first (they need to start cooling immediately)
2. Furnace or HVAC (restore climate control)
3. Sump pump (if applicable — it may need to run immediately)
4. Router and modem (restore connectivity)
5. Computers, TVs, and other electronics last

Step 3: Inspect your food

Anything in the refrigerator that has been above 40°F for more than 2 hours should be discarded — especially meat, poultry, seafood, dairy, eggs, and cooked leftovers. Do not rely on smell or appearance. Foodborne bacteria do not always produce obvious spoilage signs.

Freezer food that still has ice crystals or is at 40°F or below can be refrozen or cooked immediately. If in doubt, the FDA’s rule is simple: when in doubt, throw it out. A $50 grocery run is cheaper than an emergency room visit.

Step 4: Check your equipment

Walk through the house and check that everything that should be on is on:

• Refrigerator and freezer are running (listen for the compressor)
• Furnace or AC is cycling normally
• Sump pump has not tripped its GFCI (GFCIs often trip during restoration surges — press the reset button)
• Internet is back online (router and modem may need a manual reboot)
• Security system is reconnected and armed
• Garage door opener is functioning (some lose their programming after a prolonged outage)

Step 5: Restock and learn

Refill your water bottles, recharge your power bank, and restock any food you used. The outage kit should be ready for the next outage the day after this one ends.

Write down what went well and what did not. Did you have enough light? Did the backup power source perform as expected? Was the outage longer than you had prepared for? A five-minute note now is worth an hour of scrambling next time.

Real-World Lessons: The Iberian Blackout

The April 2025 Iberian blackout was not a theoretical exercise — it was a real event that affected millions. I wrote a detailed analysis of what happened and what it taught us about grid resilience here: Iberian Blackout 2025: Lessons for Homeowners. The short version: widespread, prolonged outages are not just a developing-world problem. They happen in modern infrastructure, and the homeowners who fared best were the ones who treated backup power as part of their home infrastructure, not an afterthought.

The Bottom Line

Power outage preparation is not about buying the most expensive generator. It is about doing the small things that cost almost nothing — freezing water bottles, bookmarking the outage map, unplugging electronics before the surge hits, knowing your food safety timeline, and respecting generator safety — before you need them. The restoration surge kills more electronics than the outage ever does, and carbon monoxide kills more people than either.

Do the pre-outage checklist once. It takes an hour. The rest is just knowing the order of operations when the lights go out, and — most importantly — when they come back on.