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We Review the Best Whole Home Backup & Standby Generators

whole house generator installation in Atlanta GA

Are you looking for a whole house generator system to supply you and your family with power during emergency situations and power outages?

In this article we're going to help you determine how much power you need and which models are best suited for your particular geographic area. 

If you are looking for a smaller generator capable of running just a few necessities check out our 2000w inverter generator reviews.

Home standby generators can offer you and your family peace of mind that you'll have power in the event of a natural or man-made disaster.  These generators are ready 24/7 and can switch on within seconds of power loss. 

How to Choose a Standby Generator for Your Home

The first step in determining the right sized generator for your needs is to decide which components of your home you would like to power.  Standby generators can power an entire home, or only selected circuits.

There is a direct correlation between the power output and price on most models so it helps to have a basic understanding of the devices you'll need in the event that you lose electrical power.

You can use the table below to calculate your power requirements based on power consumption of common household appliances. 

**It's important to remember that appliances with motors such as AC units, water pumps, and furnaces can pull 2 to 3 times their specified wattage upon startup so make sure the generator you select has enough capacity to handle this startup load..**

Our Top Pick: Briggs & Stratton 20,000W

briggs and stratton standby generator
  • Transfer Switch Included (150Amp)
  • Operates on Propane or Natural Gas
  • Industrial Grade Engine
  • Simple installation (still requires electrician)
  • Senses Power Loss and Switches on Automatically

Wattage Calculation Table

Appliance

Wattage

Appliance

Wattage

Refrigerator / Freezer

600-800

Air Conditioning

2,000 - 4,000

Electric Furnace

5,000-25,000

Coffeemaker

400 - 800

Electric Range

2,500

Electric Range (Oven)

5,000

Table Lamp

150

Hair Dryer

1,200 - 1,500

TV

100-350

Sump Pump

1,500

Radiant Heater

1,300

Vacuum

700 - 1,400

Toaster

1,100 - 1,700

Space Heater

1,250

Microwave

1,200

Water Heater

3,000 - 4,500

Lighting

500 - 1,000

Water Pump

1,000 - 2,000

Broiler

1,400

Computer

500 - 2,000

*The wattages listed above are approximations.  You can find the exact power requirements of all your household appliances in the users manual or online.

While it's great to have power for entertainment devices such as a TV, your initial focus should be on the things you NEED.  Items such as the refrigerator, furnace,  and water heaters and pumps should get first priority.  Then non-critical devices such as coffeemakers, TVs, and hair dryers should be considered.

How Does A Standby Generator Work?​

Let's take a quick look at how these systems are designed to work.

  1. The controller within the generator monitors voltage coming from your utility.
  2. If there is an interruption in power the controller waits 15-20 seconds before telling the generator to start.
  3. Within seconds of startup the automatic transfer switch (ATS) switches your home to power from the generator.
  4. Within 15-20 seconds the generator begins supplying power to the house.
  5. Once the controller senses that utility power has been restored it switches back and signals to the engine to shut down after a cool down period.  The controller then begins monitoring the utility power again.

Generator Sizing: Calculating Your Power Needs

Once you've got a list of all the appliances you need simply add all of the wattages together.  Again, remember that some items can pull 2 to 3 times more power at startup so this needs to be incorporated into the total. 

You can then use this number as the starting point for selecting the best generator for your home.

​You'll also need to know the total amperage your devices require to determine the size of the transfer switch.  Amperage can be determined with the following formula:

Amps = Total Watts / Voltage

So a 1000W device that plugs into a 120V outlet would pull roughly 8 amps.

Fuel Source

Another important consideration when choosing the type of generator you'll need is the fuel source that will be used to power it.  There are a wide variety of options.  But permanently installed generators typically run on natural gas or liquid propane.  Diesel options are also available, but require storage tanks.

**Those in earthquake prone areas should give consideration to propane as natural gas lines can be ruptured thus denying your generator it's fuel source.**

Installation & Costs

Unless you are a qualified electrician it's generally better to have a professional install your standby generator.  At a minimum connections must be made to your homes electrical system.  And depending on your chosen fuel source it may require gas hookups as well.

Part of the installation also involves adding a transfer switch.  There are a couple different varieties.  Manual versions require you to fire up the generator and switch over to using it as your primary power source. 

Automatic versions can sense when the power goes out, fire up the generator, and switch to it's power once it's online with no work required from you.  Obviously the automatic type systems are more convenient, but also involve more costs.

When it comes to providing backup power reliability is key.  These three models offer enough output to power essential services such as heat, AC, and water and have enough power left over to operate lights and other non-essential items.

Generator installation costs can vary depending on your area and how much you can do yourself.  ​You'll need a flat, level slab of either concrete or pavers on which to place the unit.  An electrician will be needed to install and hookup the wiring and transfer switch.  You'll also need to get the gas hooked up.  You should expect to pay somewhere between $1,000 to $1,500 for installation.

​Code Requirements

Your local code authority will have the final say in electrical, gas, and plumbing installations.  The codes will vary by locality but here are a few things they typically specify:

  1. Distance of generator from house and from electrical service feed (meter etc)
  2. ​Generator should be located away from windows or doors that would allow exhaust to enter the home.
  3. Some localities require a concrete pad for the generator.
  4. Specifying types of fuel storage allowed, where it should be stored, and how large they can be.

The contractors you hire should be well versed in local codes and in ensuring that your installation is performed in accordance with these codes.

Our Top Pick: Briggs & Stratton 20,000W 40484 Reviewed

whole house standby generator

The Good

  • Tons of power
  • Industrial grade engine
  • Simple Installation
  • Solid Warranty
  • Quiet Operation 68.4dB

The Bad

  • Expensive
  • Heavier than other units in it's class

Overview

briggs and stratton house generator

When it comes to reliability, the 40484 generator from Briggs & Stratton is a beast.  It offers 20,000 watts which is enough to power 2 air conditioning units as well as a whole host of other items.  It easily takes first place in our best standby generator category.

The package includes a 150 Amp transfer switch.  This is large enough for most residential applications, but you should calculate your total amperage to be certain.  The unit will automatically sense when power is lost and switch on.  This means that within minutes your power will be restored.  ​

It can operate on both propane or natural gas, giving you a reliable source of power during even extended outages. 

Features & Performance

One of the biggest selling points of this generator is the Briggs & Stratton "Managed Whole House Power​" module.  This intelligent system allows you to power multiple high wattage devices simultaneously.  This enables you to power most of the appliances in your home in addition to two air conditioning units.

The motor is built to industrial specifications and is designed to last.  The displacement is 993cc and it consumes 2.31 gallons per hour of fuel at a 50% load using liquid propane (187 ft3 /hr natural gas).

​Fuel consumption is as follows:

Natural Gas ft³/hr (m³/hr)

1/2 Load - 187 ft³/hr
Full Load - 260 ft³/hr

Liquid Propane (gal/hr)

1/2 Load - 2.31gal/hr
Full Load - 3.75gal/hr

The noise level is comparable to an idling car.  Basically it's quiet enough that you and your neighbors should never hear it. 

The unit comes with a 4 year warranty.

Installation Notes​

The unit does require level ground for installation so you'll either need a concrete slab or other solution.  It can be located as close as 18" from your home so it's ideal for neighborhoods with small lot lines.

Serious DIYers can handle most of the installation themselves.  But the installation of the transfer switch involves working with the 240V service feed to your home.  This should be handled ONLY by a qualified electrician. ​

Final Verdict:

While the Briggs & Stratton costs a bit more than the second place Generac, the extra power can mean all the difference in a medium to large sized home.  Powering multiple AC units in addition to all your other household devices ensures the least amount of disruption for you and your family.

Second Place:  Generac Guardian Series 16kW (6462) Reviewed

The Good

  • Clean Power
  • Powerful engine
  • Simple Installation
  • Solid Warranty
  • Quiet Operation 66dB

The Bad

  • Less power for the money
  • Less fuel efficient running natural gas

Overview

generac standby generator

​The Guardian Series from Generac is another solid line of home standby generators.  The 6462 is a 16,000W unit that can run on either liquid propane or natural gas.  The unit comes with a 200A automatic transfer switch and can run most of the devices in a small to medium sized home.

Generac has a reputation for quality and this unit is no exception.  It comes with a 5 year warranty and Generac has an extensive network of installation and maintenance resources around the country.  They also offer 24/7 support for their generators. ​

Features & Performance

While it is only rated for 16,000W the Generac does has a 992cc (vs 993cc for the B&S) engine.  It's powerful enough to power most small homes including an AC unit, water pumps, heaters, and a variety of small electronics.  The engine is enclosed in a sound dampened enclosure that is powder coated to ensure longevity. 

Generac's "True Power" technology provides clean and stable power at less than 5% harmonic distortion.  This is essentially as clean or better than the power you're currently getting from your utility company.

The unit can run on either liquid propane or natural gas.  Liquid propane requires at least a 250 gallon tank stored on-site. 

The 6462 standby generator comes with a composite mounting pad, but it still requires a flat, level space for installation.  Ideally this would be poured concrete in an area that is not prone to flooding.  Generac dealers can supply a pre-cast concrete form that is produced specifically for this model.

​Fuel consumption is as follows:

Natural Gas ft³/hr (m³/hr)

1/2 Load - 193 (5.47)
Full Load - 312 (8.83)

Liquid Propane ft3/hr (gal/hr) [liter/hr]

1/2 Load - 72.4 (1.9) [7.2]
Full Load - 130 (3.19) [12.07]

Installation Notes

As with the other generators in this comparison it is recommended to have the Generac professionally installed.  This will ensure that all local codes are met and optimal performance of the unit is achieved.  As previously mentioned the unit comes with a 200A automatic transfer switch that should be installed at the service feed by a licensed electrician. 

For an additional cost you can also purchase the pre-cast concrete slab that is specifically designed for Generac products. 

Final Verdict:

Generac has been making some of the best standby generators on the market for a long time.  The Guardian series is a very robust and reliable product.  It finished second in our comparison because for slightly more in price the Briggs & Stratton offers more power, flexibility, and better fuel efficiency when running natural gas.

Budget Option: Generac Guardian Series 11kW (6438) Reviewed

The Good

  • Clean Power
  • Powerful engine
  • Simple Installation
  • Solid Warranty
  • Quiet Operation 63dB

The Bad

  • Less power for the money
  • Less fuel efficient running natural gas

Overview

​The Guardian Series from Generac is another solid line of home standby generators.  The 6438 is a 11,000W unit that can run on either liquid propane or natural gas.  The unit comes with a 200A automatic transfer switch and can run most of the devices in a small to medium sized home.

Features & Performance

Rated for 11,000W this model has a 530cc engine.  While not as powerful as it's bigger brother, it's capable of powering most small homes' essential items including an AC unit, water pumps, heaters, and a few small electronics.  The engine is enclosed in a sound dampened enclosure that is powder coated to ensure longevity. 

Utilizing Generac's "True Power" technology it supplies clean and stable power at less than 5% harmonic distortion.  This is basically as good or better than the power you're currently getting from your utility company and should be ideal for sensitive electronics as well as larger appliances.

​Fuel consumption is as follows:

Natural Gas ft³/hr (m³/hr)

1/2 Load - 124 (3.51)
Full Load - 195 (5.52)

Liquid Propane ft3/hr (gal/hr) [liter/hr]

1/2 Load - 42.8 (1.18) [4.45]
Full Load - 70 (1.92) [7.28]

Installation Notes

Professional installation of this generator is highly recommended.  This will ensure that all local codes are met and optimal performance of the unit is achieved.  As previously mentioned the unit comes with a 200A automatic transfer switch that should be installed at the service feed by a licensed electrician. 

The unit will run on either natural gas or propane.  Generac recommends at least a 250 gallon liquid propane tank. 

Final Verdict:

While not as powerful as it's larger sibling, the 6438 is a great generator for smaller homes.  It most likely won't allow you to run everything in the house, but can handle the essential appliances as well as water heater, AC, and water pumps.  Overall it's  great budget option.

About the Author Jason

Jason is a work from home dad who has a passion for DIY projects, yard work, and SEC Football. His background is IT, but he's always fancied himself as a part-time ship welder, landscaper, and short order cook. During the week he can be found on his laptop 10 hours-a-day, but on the weekends he escapes to the local DIY Cave to play with REAL toys.