Battery Backups, Generators, or Both? Here’s How to Decide

Power outages used to come without warning and wouldn’t last more than a day, but now they’ve become a regular part of Bay Area life. Natural disasters, brownouts, and planned power outages mean we need to be ready to keep our homes running with a backup power source. Battery backups and generators are the two main backup power sources on the market right now. Let us walk you through the benefits of each one.

Comparing Battery Backups and Generators

Battery Backups

  • Can store grid or solar panel energy 
  • Runs on electricity produced by solar energy
  • Can schedule usage
  • Good for TOU plans
  • Lower upfront costs which can be as low as $12,000-$13,000 after tax credits, and overall long-term costs tend to be lower
  • Requires a full day to install
  • Run quietly
  • Emissions-free
  • Low maintenance
  • Can power smaller items for longer
  • Longer warranty


  • Does not store energy
  • Runs on fuel
  • Automatically starts in power outage 
  • Best not to run while you have power
  • Higher upfront costs that start at $17,000 and up, and overall long-term costs tend to be higher
  • Requires a full day to install
  • Tend to be noisy
  • Put out carbon monoxide
  • Higher level of hands-on maintenance, comparable to any other small engine
  • Can power a whole home for longer
  • Shorter warranty

A battery backup is basically a giant rechargeable battery connected to your house. Batteries can store electricity that comes from the power grid or from your home’s solar panels. It can power smaller items, such as the lights, the fridge, and the TV and internet for a long time. If you want a battery backup system that can provide power to larger items, such as your air conditioner, hot tub, pool, electrical oven, or other items that draw a larger amount of energy, you can install more than one battery so there is more reserved energy to pull from

Battery backups can be mounted to the wall or floor and usually have a low profile. Depending on your needs, battery installations can be more expensive than generator installations up front, but they don’t require a lot of maintenance. 

Battery warranties are often based on its expected effectiveness, so if a manufacturer thinks a battery should hold 70% of its charge after ten years, or maybe that it will maintain its effectiveness up to a certain amount of charging cycles, the warranty will usually reflect that. 

Generators also connect to your home’s electrical system but need fuel to run, usually natural gas, liquid propane, or diesel. While generator setup costs can potentially be less expensive than battery backups, they can still run into the thousands of dollars. A generator is a motor, so it will need maintenance such as monitoring the fuel level, changing the oil and air filter and replacing spark plugs. 

A generator creates the electricity needed on-demand instead of pulling from a reserve. It could be connected to your home’s natural gas or propane so you wouldn’t have to manually top it up, and it can provide power to larger items (A/C, hot tub, pool, etc.) for a long time. A generator will kick on automatically when the power goes out, but unlike a battery, it cannot be run while there is power coming from the grid. Since generators can only run while there is no power, the money you would have spent on electricity would likely go to gas and maintenance costs to run the generator. 

Generator life spans are usually easier to predict than batteries. For example, if a generator is expected to run for 3,000 hours, you can estimate how many hours a year you’ll use the generator and calculate an approximate time for when it would need replacing.

How to Decide Between a Battery Backup, a Generator, or Both

Imagine these two scenarios:

Homeowner A owns a house on a smaller property in the East Bay. The homeowner believes the house only gets a little bit of morning sunlight because of the direction of the windows. The homeowner is considering a backup power option because the pre-planned grid shutoffs by the local power companies are creating a lot of challenges. This homeowner wants just enough power to run the small items during a power outage. 

Homeowner B owns a larger house with a pool in the South Bay. The house gets lots of sunlight throughout the day. This homeowner owns an electric vehicle and wants to charge it at home. Even if there is a power outage, the homeowner wants to run everything as always.

What should each of these homeowners do? Here are three important points that each of these homeowners (and you) should consider before deciding:

  • Budget
  • Needs
  • Location

Budget. Backup power costs include the up-front installation and the continuing maintenance to make your investment last for as long as the manufacturer expects it to last, if not longer. 

  • Things to think about: How much money can you afford to spend to install your backup power source? You probably won’t want to consider a system that puts you too far over-budget up front. How much money can you afford to spend to maintain your backup power source? In some cases, backup power sources can be somewhat cheaper to install but more costly to maintain. Something that might affect your budget considerations would be your needs.

Needs. The amount of energy you hope to use during a power outage will factor into what you need to buy, whether it’s how many battery backups or how powerful of a generator.

  • Things to think about: What will you use your backup power for? If you only need to run the fridge, turn on the lights, watch TV, and use the internet, your backup power system could be considerably simpler than if you want to run your pool, hot tub, A/C, electric oven, health-support devices, or even charge your electric vehicle. 

Location. The amount of sunlight your house gets could affect whether your batteries would be better connected to solar panels or to the grid. The layout of your property can affect whether a generator is a realistic option for you. 

  • Things to think about: Where is your home? If you live next to the bay where it naturally stays cooler, you probably don’t need to worry about running the A/C. Does your house get good sunlight? If not, it’s likely better to connect your batteries to the grid. What is the layout of your property? Generators typically are required to have three feet of space on each side, they can’t be near any windows that can open, and the generator itself is usually 4’ x 2’ x 2’, so the layout of your property could affect how practical a generator installation would be.

You’ve probably used these same principles when buying a phone or laptop: How much money can you spend? How much storage do you need? What will you use it for? Where would you be using it most often? These same principles can help you identify what you really need.

Get Expert Suggestions Before Deciding

Battery backups and generators each have their own benefits. In the end, how will you know what’s right for you? If you’re already looking into backup power options, you already know how big of an investment this would be and want to get this right. Getting a professional opinion to complement your research can provide answers to questions you didn’t know you needed to ask. Expert advice can give you the confidence you need to decide how to light the way when the power is out.