Whole House Battery Backup vs Generator: Which Power Solution Is Right for You?

Home energy storage · Nov 24, 2023

As energy problems become more frequent, households suffer more from power outages or increased electricity prices. Those two problems could leave people’s lives and wallets vulnerable.

Home batteries and generators are two common choices to handle home energy problems.

In this article, we will give a thorough introduction to these two options, providing you with a solid foundation to decide which option suits your situation better.

Exploring Battery Backup Systems

home battery system

How do batteries for backup storage work?

Batteries can store energy you can use when needed.

The most common usage of home batteries is to charge them with solar energy products, which are free and limitless. The battery is charged during the daytime from the solar system, and you can use the battery to power household appliances at night or during an outage.

Or you can just save the energy in the battery and only use it for outages.

Pros of battery backup systems

There are many advantages to battery backup.

1.    Convenient.

For homeowners who have a solar system, a home battery system is a very good choice. Current home energy management systems with battery storage were primarily designed for existing solar systems, so it is quite convenient to charge batteries from solar panels.

Even if there is no solar system, batteries can be charged from the grid or wind turbines. With advanced home energy management systems, batteries can be charged from generators or even from EV batteries.

2.    Safe and reliable.

Most home batteries are high quality due to the federal and state regulations. That is why home batteries are safe and reliable as a backup option.

When there is a power outage, the management system can immediately switch to batteries to power the home.

3.    Cost-effective.

Since solar is the most common energy source used to charge batteries, battery storage can be quite cost-effective. The biggest cost is the upfront investment in such a technology. From there, the batteries mean that you make far more efficient use of your solar investment by more effectively using solar energy production.

4.    Quiet and environmentally friendly.

Batteries are quiet when working and produce no harm to the environment. This feature is very attractive compared to alternatives such as generators.

5.    Manage home energy.

Smart home energy management systems will allow you to monitor and control the energy through a smart app. You can choose when and how to consume your energy from all sources so that you get the highest energy efficiency.

Franklin Home Power

Cons of battery backup systems

1.    Larger upfront costs.

The upfront cost of a home energy system with battery storage is high compared to a portable generator, and a bit higher compared to a standby generator.

However, with the expansion of the use period, a battery backup system could be much more cost-saving compared to generators since batteries require low operating costs, unlike generators which require constant investment in fuels and maintenance.

2.    The run time is short during a prolonged outage.

A battery has a fixed maximum storage. The mainstream storage of home batteries ranges from 5 kWh to 15 kWh, which may not be sufficient for a big house with many household appliances to last in a prolonged power outage.

This problem can be solved by installing more batteries. Usually, during the purchasing phase, installers will confirm with you the necessary number of batteries that can meet your demand, even under circumstances of prolonged power outages.


Understanding Whole House Generators

whole house generator

How do whole house generators work?

A whole-house generator can power necessary household appliances for the whole home during an outage. Normally, it is fed with diesel, natural gas, or liquid propane and can automatically start when the power goes out.

Pros of whole house generators

1.    It powers home immediately.

Generators can automatically turn on when they detect grid failures. Homeowners will experience a smooth energy transition without life being disturbed.

2.    It can last longer in a prolonged outage.

Generators can supply power non-stop for a long period if there is sufficient fuel. Compared to solar and batteries, which may be limited by weather conditions and battery storage, generators can work continuously and provide ease of mind.

Cons of whole house generators

1.    Noisy.

The most obvious con of a generator, either a standby one or a portable one, is the loud noise which can be unbearable, especially at night.

2.    Environmentally unfriendly.

As generators use natural gas or diesel as the fuel, it will produce harmful materials to the environment such as methane which is highly toxic and hazardous to the climate.

3.    Costly.

A standby generator requires a big upfront investment as well as follow-up costs for fuels and maintenance. Usually, a generator requires one major maintenance per year. All expenses added could be costly.

4.    Access to fuel.

During a prolonged outage, especially due to weather or a natural disaster, access to fuel can be limited.


Batteries vs. Generators

home battery

Power output and capacity

For battery systems, the power output is usually around 5 kW. Most battery systems on the market are available for expansion with more batteries stacked, enhancing the power capacity. For instance, 4 batteries could provide a 20 kW power capacity.

Normally, 15 kW - 20 kW is enough for residential scenarios and can start heavy appliances such as ACs and water pumps.

For generators, the power output can range from a single digit to hundreds of kilowatts, just like batteries.

Both options are flexible, and a good installer can help the homeowner evaluate options.

Installation requirements and cost

Professional installations are required for both battery systems and standby generators. Portable generators are easier to install so homeowners may be able to do that themselves.

The product costs of battery systems and standby generators are within the same price range. Total initial costs mainly depend on physical installation.

Maintenance and upkeep

The maintenance for battery backup systems is quite easy and almost negligible. Once the battery is set up, it will take very little maintenance each year unless any failure occurs. Correspondingly, the maintenance cost is negligible.

For generators, the maintenance cost can be major. They must regularly be tested by running and require at least one maintenance per year with a cost range of $200-600.

Expected lifespan

The expected lifespan for battery systems is around 10 years, a common warranty period for major brands.

For generators, the expected lifespan could be much longer, reaching 20-30 years.

Noise and environmental impact

Whole home battery backup systems do not produce any noise generally. Nor do they produce anything harmful to the environment.

For generators, the noise they produce is often annoying, and harmful emissions will be produced if they are fueled with diesel or natural gas.

Smart home integration

Home energy management systems with batteries can be intelligent and can be part of a smart home integration. You can control and manage your home energy through a smartphone app, thus increasing your energy efficiency.

While generators can automatically turn on when detecting power outages, they typically don’t have the flexibility or intelligence unless integrated with a whole home energy management system.

Reliability and availability

Both battery systems and generators are safe and dangerous at the same time. They are safe due to high standards of regulations. They are dangerous since they produce electricity which can be dangerous.

As a relatively new technology, the battery market is maturing with reliable customer services and warranties. The generator market is already very mature and provides decent services and warranties.

Both products are easy to get throughout the country.


portable generator

Using House Generators and Battery Backup Systems Together

A whole home energy management system that integrates battery backup and a household generator may be the best solution. As introduced above, solar energy production is variable depending on the amount of sunshine. A generator has many side effects, but it can supply power during prolonged outages as a good supplement to the battery system. A generator can be used to charge the batteries when their charge is low, then shut off to extend the length of operations of the generator during a prolonged outage.

Enhancing your power security

The more energy sources you integrate, the more energy security you will have. Combining solar, batteries and generators is a better solution than having either option alone.

Franklin Home Power

Choosing Your Power Solution

Budget and cost-effectiveness

The first factor you need to consider is the cost. For battery systems, the upfront cost is big with low operating costs. The standby generator costs the most considering both capital and operating expenses. The portable generator is the cheapest, achieving the minimum functions compared to the other two options.

Space and installation constraints

Installation should also be taken into consideration as certain places are not suitable for batteries for environmental reasons such as sufficient shade. The operational environment should also be considered.

Backup duration and fuel requirements

You should also consider the outage circumstances in your area. Are outages long and frequent or just occasional?

How convenient is it to get fuel regularly? What is that cost?

whole house batteries

Case Studies: Real-Life Applications

There are examples of home energy systems with batteries, showing people achieving levels of energy independence and cost savings.

They include a success story where a battery system integrates well with a generator, supplying power on an isolated island.



1.    What's the main difference between a whole-house generator and a battery backup system?

Generators create power while batteries store power. A generator alone provides power directly to the home. A battery is used to store power from solar, the grid, and generators, to be used when necessary to power the home.

2.    How long can a battery backup system typically power my home during an outage?

It depends on your household power demands and the number of batteries. If you install enough batteries, your battery backup system will be able to power your home for a very long time. Combined with solar or generator power supply, battery storage can power the home for a long time.

3.    Are whole house generators suitable for smaller homes, or are they primarily for larger residences?

It depends on how many appliances you want to run. The appropriate-sized generator can supply power for any home.

4.    What are the primary maintenance requirements for batteries and generators?

A battery system does not require maintenance unless there is a failure, as system checks happen automatically. A generator will require regular maintenance to make sure is in operational condition.

5.    Can I install a battery backup system or a whole house generator myself, or do I need professional installation?

You do need professional installation help for battery systems and standby generators, as they are complex, high-voltage devices.

6.    How do I determine the ideal size or capacity for a whole-house generator or battery backup system for my home?

Consult a professional installer to calculate your daily power needs so the appropriate-sized system can be designed.

7.    Do these systems come with warranties, and what kind of customer support should I expect for installation and maintenance?

Yes, both systems have warranties. The customer support you will get differs among products. You should do the research before making the decision.

house generator


Final Thoughts

Battery backup systems and generators are the two most common products that people get to back up their homes and gain energy freedom.

After reading this article, we hope you will get a general idea about each option and be able to make the decision that best suits your scenario.


Energy Independence with FranklinWH

FranklinWH energy management and storage system integrates solar, grid, battery, and generator, monitors and manages home energy, providing robust backup capability and increasing solar ROI and energy efficiency.

Learn more about FranklinWH here.

Still have questions? Connect with our home energy experts here.

Franklin Home Power