How Do Whole-House Generators Work?
Power up your whole-house generator with the key details
A whole-house generator provides an alternate source of power in case of blackouts or other power outages.
These large generators can power whole rooms or homes, and typically use long-lasting fuels like natural gas and propane.
Modern whole-house generators are automatic, switching on and moving the house to generator power when it detects an outage.
Installing a whole-house generator requires hiring a professional generator installer due to its fuel and electrical work.
For homes that experience regular power outages during extreme weather, a whole-house generator offers a more reliable source of backup power. Before investing in this emergency power source, it’s helpful to understand how whole-house generators work.
Whole generators tap directly into your home’s electrical system and provide an alternate way to power it when the electrical grid experiences problems. They are permanent installations that last for many years, switching on automatically when unexpected power problems hit. Here’s everything you need to know about how whole-house generators function.
What Is a Whole House Generator and How Does It Work?
Any home generator provides power that appliances use to run in the event of an electrical grid failure. However, whole-house generators, also called backup generators or standby generators, are large, powerful models (up to 20,000 watts or more) designed to provide usable power to an entire electric system, powering rooms, major appliances, or even the entire house. They are a common solution in areas without reliable power, frequent blackouts, or off-the-grid living.
These generators burn fuel to turn an electromagnetic motor and generate an electrical charge, which is regulated and passed into a home’s system. Whole-house generators need a lot of fuel to run for long periods of time, so popular fuels include natural gas or propane.
Modern whole-house generators are largely automatic. They are triggered by a power outage or similar problem and switch the home’s electrical system over to generator power as needed. The generators still require maintenance, with the average maintenance session costing around $270.
How to Prepare for Whole-House Generator Installation
Installing a whole house generator is a job for a professional generator installer that may also require fuel work, like hooking up natural gas connections or installing a permanent fuel tank. An electrician will need to install a transfer switch near your electrical panel, which switches home electricity from the power grid to the generator when necessary.
Follow these prep steps before installing a whole-house generator:
Get price estimates from at least three generator installers to find the best deal
Determine the generator’s fuel type
Secure the proper storage for fuel type
Determine what size of generator you need for your home
What Types of Fuel Does a Whole House Generator Use?
Whole-house generators can operate with several kinds of fuel, and some can even switch between fuels with the right settings or conversion kits. The main fuel options are:
Propane: Propane is long-lasting and you can arrange for deliveries to keep a large propane tank full when storm season approaches. However, you need to install a large propane tank first, which adds to the expense and space required.
Diesel: Diesel is a stable, affordable, and readily available fuel source. However, diesel doesn’t always work well in very cold weather, and it tends to lose its shelf life after about two years, so it may need more frequent replacement.
Natural gas: Natural gas generators connect permanently to a natural gas line to supply fuel, similar to a gas fireplace. Natural gas is very affordable and the permanent connection means you don’t have to worry about refilling. However, natural gas is uncommon in rural areas, so it won’t always be an option for homeowners.
Whole House Generators vs. Portable Generators
Don’t confuse whole-house generators with portable generators. Both are made for homes and often made by the same brands, but portable generators are much smaller and don’t provide long-term or extensive backup power.
Portable generators are not connected to your home through a transfer switch or similar permanent setup. They only have enough wattage to power up a small room or a few important appliances for a limited amount of time. They also have limited fuel capacity, and can’t usually connect to a permanent fuel source like natural gas (gasoline models, on the other hand, are more common). Portable generators are more suitable for infrequent problems or powering up a workstation far from electrical grid connections.
Frequently Asked Questions
As long as they have enough fuel, whole-house generators can run for weeks at a time (400 to 500 hours) without suffering too much wear and tear. However, this type of extensive use isn’t ideal if you want to extend the life of your generator.
Two important points. First, some generators may need you to periodically check oil levels every day or so and refill as necessary for safe operation. Second, if your generator uses a fuel tank, keep it regularly full so it doesn’t suddenly shut off. Many backup generators can run through a full tank in a day when they are powering large portions of a home.
Generators are usually sized by running watts and starting watts. Ideally, you’ll want a generator that can offer both the necessary running watts and starting watts for everything you need to power without going beyond 90% of its capacity. Calculate your home’s electrical load based on the breakers in your home or adding up the appliance and lighting needs of connected rooms.
It’s a bad idea to refuel a whole-house generator while it’s running. Trying to fill a running generator is difficult and increases the risk of a fire or explosion. Instead, the recommended procedure is shutting down the generator, switching off your electrical system, then refilling it before turning it all back on. For whole-house generators, that means picking the right time when no household activities will be interrupted.
Whole-house generators can last 20 to 40 years with normal operation and proper maintenance. If you look up the specifications for your generator, you may be able to find a lifespan rated in hours of operation. Life expectancy will vary depending on how often and for how long you use the generator each year. Choosing a fuel with low impact like natural gas or diesel can help generators last as long as possible.
