A battery backup sounds pretty nice, but you’re probably asking yourself, “What can it actually run?” A fridge? Probably. Your Wi-Fi router and a few lights? Probably that, too. But what about your air conditioner or washing machine?
That’s where figuring out what a home battery backup can actually power gets a little tricky.
A battery might have enough stored energy to keep several smaller appliances running for hours, yet struggle to start a single high-demand appliance. And even if it can power something, that doesn’t necessarily mean it’ll keep running all day.
Before you start picturing life carrying on as usual during the next power outage, it’s worth knowing what your battery can realistically handle.
How Battery Backup Power Actually Works
A home battery backup stores electricity for you to use when the power clocks out for a bit. Depending on how your system is set up, it can charge using electricity from the grid, solar panels, or both.
When an outage happens, a properly configured system can automatically switch to battery power, keeping your selected appliances and circuits running.
There are two numbers that help explain what a battery can handle:
- Kilowatts (kW): How much power the battery can deliver at one time. This determines how many appliances it can run simultaneously and whether it can handle larger electrical loads.
- Kilowatt-hours (kWh): How much energy the battery can store. This helps determine how long your appliances can keep running before the battery needs to recharge.
Think of it this way: Your battery might have plenty of stored energy, but if your AC needs more power to start than the system can deliver, it won’t be able to run it. If you just wanted to keep a few lights and an outlet or two running, that same battery might support them for hours.
The other thing to consider is how your home is wired for backup power. Some systems are set up to specifically power essential circuits, like your fridge, lights, and internet equipment. Others can support a much bigger part of the house, provided your battery has enough capacity.
What Appliances Can a Home Battery Backup Run?
You might be surprised by how many household appliances a battery backup can handle. Refrigerators, lights, TVs, and internet equipment generally don’t eat through much power compared to larger appliances like central AC units or electric dryers.
The catch is that being able to run an appliance and being able to run it for several hours are two different things. A lot depends on the size of your battery system and what else you’re using at the same time.
Some everyday appliances barely make a dent in your stored energy. Others can use several kilowatt-hours in a single hour. Here’s a look at estimated electricity usage for some of the basics:
| Appliance or Device | Estimated Electricity Use (per Hour) |
| LED light bulb | 0.015 kWh |
| TV | 0.071 kWh |
| Refrigerator | 0.167 kWh |
| Central AC (3-ton) | 3 kWh |
| Electric oven | 2.3 kWh |
These are estimates based on the appliances operating for a full hour. Actual consumption will vary by power draw, among other factors.
Looking at that chart, you can see how a home battery could run a few lights, a TV, and a fridge for quite a while. But once you add a central AC (which also requires an additional power surge to start) to the mix, your backup battery doesn’t last nearly as long.
How Long Can a Battery Backup Run Your Appliances?
Being able to get your battery to power an appliance is one thing. Keeping it running through an overnight or even multi-day outage is a different story. A home battery backup has a limited amount of stored energy, and every appliance you use draws from that supply.
Let’s say you have a battery with 10 kWh of usable energy. Here’s approximately how long it could power a few common appliances individually:
| Appliance | Approximate Runtime |
| LED light bulb | 667 hours |
| TV | 141 hours |
| Refrigerator | 60 hours |
| Central AC (3-ton) | 3.3 hours |
| Electric oven | 4.3 hours |
These are theoretical estimates assuming each appliance runs alone, with no energy losses or additional electrical loads. Actual runtime will vary, and the battery system must have enough power output to operate the appliance.
What Determines Which Appliances Your Battery Can Power?
Say you have a battery backup with plenty of stored energy, but your central AC just won’t start up during an outage. So, what’s the deal?
Having enough energy stored in your battery doesn’t always mean it can handle the appliances you want to run. There are a few things that come into play:
- Battery capacity: The more energy your battery can store, the longer it can generally keep appliances running. Larger appliances tend to use up that energy much faster.
- Power output: Your battery can only deliver so much power at once. If you’re running multiple appliances and their combined demand exceeds that limit, the system may shut down or refuse to power certain loads.
- Startup power requirements: Appliances with motors or compressors, like refrigerators and air conditioners, often need a quick burst of extra power to start. Your battery needs to be able to handle that initial demand, too.
- Backup circuit configuration: Some systems only supply power to certain circuits in your home. If your electric oven isn’t connected to one of those circuits, it won’t work during an outage, even if your battery has plenty of energy to go around.
So, when you’re setting up your battery system, look at the appliances you actually want to keep running. You don’t want to find out during the next outage that something you were counting on isn’t actually connected to backup power.
Which Appliances Should You Prioritize During a Power Outage?
If you’re prepping for a power outage that could last a day or longer, like one of California’s PSPS outages, think about which appliances you’ll actually need.
You may want to prioritize:
- Refrigerators and freezers
- Essential medical equipment
- Lights
- Phone chargers and Wi-Fi routers
- Heating or cooling equipment, if needed
Once you’ve factored those in, you can decide which other appliances are worth using your remaining battery capacity (if any) for.
FAQ: How Many Appliances Can a Backup Battery Power?
There’s a lot to consider before installing a home battery backup, especially if you’re hoping to keep most of your household running during an outage. Here are a few other things you might be wondering about.
How much does a home battery backup system cost?
Home battery backup systems in California cost around $1,100 per kilowatt-hour (kWh) of storage capacity. At that rate, a 10 kWh system would run about $11,000, while a 15 kWh system would cost roughly $16,500.
Your final price will depend on the battery you choose, the electrical work involved, and how much of your home you want to keep running during an outage.
Can a battery backup run an entire house?
Yes, a battery backup can run an entire house. But you’ll need a system that’s up to the job. If you want to keep everything running, central AC and electric appliances included, that could take multiple batteries.
Can a home battery backup work without solar panels?
Yes, a battery backup can work without solar panels. Many systems can charge using electricity from the grid and save that energy for an outage. The catch is that once the battery runs low, you’ll generally need to wait for grid power to return before it can recharge.
Can you run multiple appliances on a battery backup at once?
Yes, you can run multiple appliances on a battery backup, as long as their combined power needs don’t exceed what your battery system can deliver. You could potentially keep the refrigerator running, watch TV, and have a few lights on at the same time.
Just remember that the more appliances you use, the faster you’ll go through your stored energy.
Will a battery backup automatically turn on during a power outage?
Many home battery backup systems are designed to kick in automatically when the grid goes down. You won’t have to trek out to start a generator or manually switch everything over. The exact transition does depend on your equipment, and some devices may briefly lose power during the switch.
Can a home battery backup power medical equipment?
Yes, many home battery systems can power equipment like CPAP machines and oxygen concentrators. The important part is making sure the battery can meet the equipment’s power needs for as long as you’ll need it.
If someone in your home depends on electrically powered medical equipment, talk with your electrician and the equipment manufacturer about backup requirements and a separate emergency power plan.
How long will a home battery backup last during an extended outage?
The length of time a home battery backup will last during an outage depends on how much energy your battery can store and what you’re asking it to run. A battery powering your fridge and a few lights can run a whole lot longer than one running your central AC.
Keep the Lights On When the Grid Goes Down
Nobody wants to spend a power outage worrying about the food in the fridge, a dying phone battery, or how long the house will stay comfortable without AC. Having a home battery backup can take a few of those worries off your plate, especially when California’s PSPS season rolls around.
Alpha Omega Electric can help you figure out which appliances you want to keep running and what kind of battery backup system makes sense for your home. Contact us today to discuss your home battery backup options.
Sources & References
- California Public Utilities Commission – “Public Safety Power Shutoffs (PSPS)”
Explains why California utilities implement Public Safety Power Shutoffs during elevated wildfire risk, what customers can expect, and how to prepare for planned outages.
https://www.cpuc.ca.gov/psps - Silicon Valley Power – “Appliance Energy Use Chart”
Provides estimated electricity consumption for common household appliances, including refrigerators, air conditioners, lighting, kitchen equipment, and electronics.
https://www.siliconvalleypower.com/residents/save-energy/appliance-energy-use-chart - U.S. Department of Energy – “Solar Integration: Solar Energy and Storage Basics”
Explains how energy storage systems work with solar power, how batteries store electricity for later use, and their role in providing backup power during outages.
https://www.energy.gov/cmei/systems/solar-integration-solar-energy-and-storage-basics
