Power outages are one of the most common household emergencies — and one of the most disruptive. When the grid goes down, most people realize quickly how much of their daily life depends on electricity.
But backup power is also one of the most confusing preparedness topics. Watts, amp-hours, kilowatt-hours, inverters, generators, solar panels — the terminology alone is enough to make most people give up and hope the power comes back on quickly.
This guide cuts through the jargon. It explains what backup power can realistically do for a household, what the main options are, and how to figure out what you actually need — without overbuying or underbuying.
What Backup Power Can Realistically Do
Let's start with an honest expectation-setter: most backup power solutions are not designed to run your whole house.
Whole-home backup — the kind that keeps your HVAC, electric stove, water heater, and all your lights running indefinitely — requires a permanently installed standby generator connected to your home's electrical panel. That's a significant installation and investment.
For most households, the realistic goal of backup power is more focused:
- Keep phones and communication devices charged
- Power critical medical devices (CPAP, nebulizer, etc.)
- Run a small fan or space heater for comfort
- Keep a few lights on
- Power a small refrigerator or cooler for medications or food
- Run a laptop or radio
That's a much more achievable goal — and one that makes a real difference during a 24- to 72-hour outage.
Understanding the Basics: Watts and Runtime
You don't need to become an electrician, but two concepts help everything else make sense:
Watts = How Much Power a Device Uses
Every electrical device uses a certain amount of power, measured in watts. A phone charger uses about 5–20 watts. A laptop uses 30–60 watts. A CPAP machine uses 30–100 watts depending on settings. A full-size refrigerator uses 100–400 watts. A window air conditioner uses 500–1,500 watts.
The higher the wattage, the faster a battery drains.
Watt-Hours = How Much Energy a Battery Stores
Battery capacity is measured in watt-hours (Wh). A 500Wh battery can theoretically power a 100-watt device for about 5 hours, or a 50-watt device for about 10 hours.
In practice, real-world runtime is somewhat lower due to efficiency losses — but this gives you a useful starting estimate.
The key question: How many watts does your critical device use, and how many hours do you need to run it? Multiply those two numbers to get the watt-hours you need.
The Main Backup Power Options
USB Power Banks
What they do: Charge phones, tablets, earbuds, and small USB devices.
Capacity: Typically 10,000–30,000 mAh (milliamp-hours). A 20,000 mAh power bank can charge most smartphones 4–6 times.
Best for: Phone charging, small electronics, short outages.
Limitations: Cannot power laptops (unless the bank supports USB-C Power Delivery), CPAP machines, fans, or any AC-powered device.
Practical note: Many households already own a power bank that sits in a drawer uncharged. Check yours. Keep it charged.
Portable Power Stations
What they do: Provide AC outlet power (like a wall outlet), USB charging, and DC output from a rechargeable battery. No fuel required. No exhaust. Can be used indoors safely.
Capacity: Entry-level units start around 150–300Wh. Mid-range units run 500–1,000Wh. Larger units go higher.
Best for: CPAP machines, laptops, small fans, LED lighting, phone charging, small appliances. Excellent for 24–72 hour outages when paired with solar charging.
Limitations: Cannot run high-draw appliances like full-size refrigerators, electric stoves, or air conditioners (unless you have a very large, expensive unit). Runtime is finite without recharging.
Recharging options: Wall outlet (before the outage), car outlet (12V), or solar panel.
Portable Solar Charging Panels
What they do: Convert sunlight into electricity to recharge a power bank or portable power station.
Output: Typically 60–200 watts for panels designed for portable power stations.
Best for: Extending the runtime of a portable power station during a multi-day outage. Excellent pairing with a power station for extended preparedness.
Limitations: Dependent on sunlight. Cloudy days significantly reduce output. Charging a large power station from a small panel takes many hours. Not a standalone power solution — works best paired with a battery.
Portable Generators
What they do: Generate electricity by burning fuel (gasoline, propane, or dual-fuel). Can power larger loads than battery-based solutions.
Best for: Running a refrigerator, sump pump, window AC unit, or multiple devices simultaneously. Useful for extended outages where battery solutions would run out.
Limitations and safety requirements:
- Generators must never be operated indoors, in a garage, or near open windows or doors. Carbon monoxide poisoning from generators is a leading cause of weather-related deaths. Always operate generators outdoors, well away from any structure.
- Require fuel storage and management. Gasoline degrades over time — use fuel stabilizer if storing for emergencies.
- Noisy. Require maintenance. Heavier and less convenient than battery solutions.
- Cannot be used in apartments or most urban settings.
Always follow the manufacturer's safety instructions for generator operation. Consult your local fire department or utility company guidelines for safe generator use.
Standby Generators (Whole-Home)
Permanently installed, automatically activated when grid power fails, and connected directly to your home's electrical panel. Run on natural gas or propane. Can power most or all of a home's electrical load.
This is a significant home improvement project requiring professional installation and permitting. It's beyond the scope of this beginner guide but worth knowing exists for households with medical equipment dependencies or other high-power needs.
How to Figure Out What You Actually Need
Rather than buying the biggest or most expensive option, start by identifying what actually matters during an outage in your household.
Step 1: List Your Critical Devices
Ask yourself: if the power went out for 48 hours, what would I genuinely need to keep running?
For most households, the honest list is short:
- Phones (communication, flashlight, information)
- CPAP or other medical device (if applicable)
- A light source
- Possibly a fan or small heater for comfort or safety
- Possibly a laptop for work
Step 2: Look Up the Wattage
Check the label or manual for each device. Or search the device name + "watts" online. Note the wattage for each critical device.
Step 3: Estimate Runtime Needed
How many hours per day do you need each device to run? Multiply wattage × hours to get watt-hours needed per day.
Step 4: Match to a Solution
- Phone charging only → A good USB power bank is sufficient
- Phone + laptop + lights → A 300–500Wh portable power station
- CPAP + phone + lights → A 500–700Wh portable power station
- Refrigerator + multiple devices → A larger power station (1,000Wh+) or a generator
- Multi-day outage → Add a solar panel to recharge your power station
A Note on Medical Devices
If someone in your household depends on an electrically powered medical device — CPAP, oxygen concentrator, nebulizer, insulin refrigeration, or similar — backup power planning is not optional. It's a medical necessity.
Contact your device manufacturer or medical provider for specific power requirements and recommendations. Some medical devices have specific battery backup options designed for them. Your local utility may also have a medical baseline program or priority restoration list for households with medical needs.
What You Can Do Today
- Find every power bank in your home and charge them fully
- List the three devices that matter most during an outage in your household
- Look up the wattage of your most critical device
- Decide whether a power bank, portable power station, or generator fits your actual needs
Frequently Asked Questions
Can I run my refrigerator on a portable power station?
A full-size refrigerator typically draws 100–400 watts and runs in cycles. A large portable power station (1,000Wh+) can run a full-size refrigerator for several hours. A smaller power station may run a compact or camping refrigerator more effectively. Check your refrigerator's wattage and calculate accordingly.
How long will a portable power station last?
It depends entirely on what you're running and the station's capacity. A 500Wh station running a 50-watt CPAP machine will last roughly 8–10 hours. The same station running a 200-watt load will last 2–3 hours. Calculate based on your specific devices.
Is solar power worth it for emergency preparedness?
A solar panel paired with a portable power station is one of the most practical combinations for extended outages. It's not a whole-home solution, but it can keep a power station charged indefinitely during daylight hours, dramatically extending your backup power capability.
What's the safest backup power option?
Portable power stations (battery-based) are the safest option for indoor use — they produce no exhaust and no carbon monoxide. Generators must always be used outdoors. Never operate a generator indoors or in an attached garage under any circumstances.
Do I need to maintain a portable power station?
Keep it charged. Most manufacturers recommend storing lithium battery power stations at 50–80% charge and recharging them every 3–6 months if not in regular use. Check the manufacturer's specific recommendations for your unit.
Backup power doesn't have to be complicated. Start with what your household actually needs, match it to the right solution, and build from there.
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