Outage planning guides
24-Hour Power Outage Plan
A one-day outage is usually about protecting food, communication, lighting, and a few comfort loads without overbuilding the backup system.
Use this planning estimate when a storm, utility repair, or short grid interruption may leave a U.S. household without power for about one day.
Suggested loads
| Load | Watts | Priority | Note |
|---|---|---|---|
| Refrigerator | 120-200 running watts | critical | Plan for cycling load and startup surge rather than assuming it runs continuously. |
| Phone charging | 5-20 watts | critical | Small load, but important for alerts and communication. |
| LED lights | 8-40 watts total | useful | A few efficient bulbs can cover key rooms with low energy use. |
| Wi-Fi router and modem | 15-40 watts | useful | Only useful if the internet provider network remains online. |
| Laptop | 30-90 watts | optional | Useful for work or information, but should be scheduled instead of left charging all day. |
Planning steps
- List only the loads you need for the first 24 hours.
- Separate running watts from startup surge for motor loads.
- Estimate watt-hours by multiplying average watts by expected hours of use.
- Add a margin for inverter losses, cold weather, battery age, and unplanned phone charging.
- Decide which loads can be run in shifts instead of all at once.
Example plan
- Duration
- 24 hours
- Estimated energy
- 1,200-2,000 Wh for refrigerator cycling, router, phones, and several LED lights
- Battery note
- A 1-2 kWh power station can cover a lean 24-hour plan when loads are scheduled and high-draw appliances are avoided.
- Generator note
- A small portable generator may cover these loads if it can handle refrigerator startup surge and is operated outdoors with proper separation from the home.
- Solar note
- Portable solar can extend runtime in clear weather, but treat solar production as a bonus rather than the only plan.
Mistakes to avoid
- Sizing the plan from appliance nameplate watts without considering actual runtime.
- Running entertainment devices before food protection and communication are covered.
- Forgetting that refrigerator startup surge can exceed running watts.
- Assuming solar panels will produce rated output all day.
Safety and limits
- Never run a fuel generator indoors, in a garage, or near open windows.
- Use battery stations within their rated output and charging limits.
- This guide is a planning estimate, not electrical installation advice.
FAQ
How much battery capacity do I need for a 24-hour outage?
Many essential-only plans land around 1,200-2,000 Wh, but your result depends on refrigerator cycling, internet equipment, lighting, and how often you charge devices.
Can a small generator handle a 24-hour outage?
It may, if its continuous output and surge rating match your selected loads. Fuel availability, safe outdoor placement, and noise rules also matter.
Related calculators
Home Outage Backup PlannerPlan 24, 48, or 72 hour backup needs for critical home loads using battery and generator estimates.Portable Power Station Runtime CalculatorEstimate how long a portable power station can run a load after efficiency losses and reserve.Generator Wattage CalculatorEstimate running watts, starting surge, and a practical generator size for selected backup loads.Refrigerator Backup Time CalculatorEstimate refrigerator or freezer backup time using battery capacity, duty cycle, and inverter efficiency.