N
The Global Insight

How do home backup generators work

Author

Ava White

Updated on April 05, 2026

A Generac home backup generator senses a power outage, turns on automatically, and delivers backup power to your home. It will run until utility power returns – whether that’s two hours or two weeks.

How do whole home backup generators work?

Whole house generators work off fuels such as natural gas or liquefied petroleum gas (LPG). Your fixed standby generator is connected to your home’s electrical wiring (usually indoors) and the fuel source. It may be started automatically or manually. The advantages of an automatic system are obvious.

Is a whole house backup generator worth it?

As a homeowner, buying a generator could spare you financial losses, like food spoilage, when power outages strike. Also, if you work from home, a standby generator is a solid investment, as it ensures you won’t suffer a loss of income due to circumstances outside your control.

How long can a backup generator power a house?

On average, a standby generator can run for up to 3,000 hours powering a medium-sized home, though it is recommended you do not run a generator for longer than 500 hours continuously. Two factors affect the amount of time a whole house generator can continue to run: Generator type. Fuel source.

Where do backup generators get their power?

Called Standby Generators, they always stand by, ready to supply power whenever needed, without operator intervention. Modern home standby generators use natural gas or propane for fuel. Where neither fuel is available or accessible, a diesel generator is another alternative.

How much fuel does a whole-house generator use?

A standard 5-kilowatt generator will typically consume about 0.75 gallons per hour. As of July 2018, the average price for gasoline is $2.89 a gallon in the United States. If you ran the portable generator for a day, that would consume about 18 gallons, meaning the cost to run the generator would be around $52 a day.

How does a Generac generator get its power?

Your Generac home backup generator runs on your existing natural gas or LP fuel supply. Save the gas cans for your other outdoor power equipment. You’ll never have to run an extension cord through a window or door again. Your Generac home backup generator safely delivers power right to your home’s electrical panel.

What is the average cost of a Generac generator?

Generac Generator Costs Generac generators cost $2,000 to $5,000 for a 7 to 24 kW whole-house unit, plus $3,000 to $5,000 for installation. Generac’s standby generators turn on automatically during power outages and run on natural gas or liquid propane.

Will a generator run longer on gas or propane?

But if running out of fuel is a concern, propane is a better choice because it will last you longer.

How long can Generac generator run continuously?

While Generac generators can run longer than 24 hours during power outages if needed, it’s still a good idea to check on your Generac every day to make sure it’s running properly. Generac recommends that you schedule professional maintenance on your backup generator every six months.

Article first time published on

Is a whole house generator tax deductible?

What you pay for a generator of any type is not tax deductible on any tax return, in any way, shape, form or fashion. However, if used to power certain medical equipment then it *MIGHT* qualify for a tax “credit”, which is completely different from a deduction.

How long do whole house generators last?

The overall lifespan will depend on the type and size of your generator, but a typical range is about 1500-3000 hours. You should be powering your generator on for about half an hour each week to exercise it, which means it will run for a minimum of 26 hours per year.

How much does it cost to run a whole house generator?

On average, a small portable generator costs about $30 to $70 per day to run, while a 15- to 20-kilowatt generator that powers the entire home will cost about $50 to $150 per day. You’ll need to factor in fuel costs, which are dependent on the type of fuel, which could be as much as $30 per day in gasoline alone.

How quickly does a generator kick in?

Your power system will start and switch power to your home within 10-20 seconds. The generator itself will run for a few seconds to stabilize voltage before power is switched from the grid to the generator.

What happens to a generator when the power comes back on?

The generator system detects a power outage immediately and waits a few seconds for the power to return. … It all happens just seconds after the power goes out. When the utility power is restored, the system reconnects the utility lines and shuts the generator down.

What do backup generators run off of?

Most units run on diesel, natural gas, or liquid propane gas. Automatic standby generator systems may be required by building codes for critical safety systems such as elevators in high-rise buildings, fire protection systems, standby lighting, or medical and life support equipment.

How much does it cost to install a transfer switch for a generator?

A transfer switch allows you to power any of those—and skip the extension cords. Plan on a cost of $500 to $1,500 for the switch, including installation, which usually takes less than a day.

How often should I test run my Generac generator?

Testing with a load should be done on a monthly or quarterly basis. Your generator’s exercise cycle may be automated by a timer, which ensures the generator is tested on a regular basis.

How long will a Generac generator run on 5 gallons of gas?

A generator can run for around 8 hours on 5 gallons of gasoline. Don’t expect any more or less with this amount of fuel.

Is it cheaper to run a generator on propane or gas?

Generally speaking, propane generators are usually less expensive than natural gas generators. Unfortunately, fuel is usually cheaper for natural gas units, but some prefer the lower initial price of the unit itself.

How long will generator run on a tank of gas?

A portable gasoline generator can run non-stop on a tank of gas but not longer without stopping. On average, it is from 6 to 12 hours, depending on the size of the generator, brand, and amount of energy consumed.

How many gallons per hour does a Generac generator use?

For example, according to Generac a 22 kilowatt generator would burn approximately 2.1 gallons per hour at ½ load and 3.6 gph at full load, while a larger 38 kilowatt unit would burn 3 gallons per hour at ½ load and 5.4 gph at full load.

How long will a 20lb propane tank last on a generator?

A generator’s operating time depends on the weight of the load. On average, generators use between two and three pounds of propane per hour. Therefore, a generator can run an average of five hours on 20 pounds of propane. However, the heavier the load, the lower the operating time.

Can a generator run 24 hours a day?

On average, a gasoline-powered portable generator will run for 7.5 to 12 hours, though some models can run for close to 24 hours. … If you plan on using the generator as a backup source of power during outages, however, you risk running out of fuel before the power comes back on.

What is the most efficient fuel for a generator?

Diesel is the most efficient of generator fuels, offering 138,700 BTUs per gallon of fuel (enough to heat an average sized room for 6 to 12 hours).

How much is a Generac generator for a 3000 square foot house?

Based on square footage, consumers will pay around $3700 to power a 1,000 to 3,000 square foot home with a Generac generator.

How much is a generator for a 2000 sq ft house?

The national average cost is between $10,000 and $20,000 for a whole house generator. Most people spend around $15,000 on an 18kW generator capable of powering a 2,000 sq. ft. home with heating, cooling, hot water, lighting, and appliances.

Where should a whole house generator be placed?

In addition to local or federal ordinances, there are standard regulations homeowners should follow. For example, most manufacturers will state that your generator should always be located outside and placed at least five feet from doors, windows, and vents, and flammable material.

How long does it take to install a Generac generator?

Once a homeowner has chosen GenerX to install their new Generac generator, the next question is; “how long will this all take?” “When will my home backup system be up and running?” The short answer was typically within 4-6 weeks – from your approved agreement until final commissioning…

What kind of gas does a Generac pressure washer take?

Fuel requirements are as follows: • Clean, fresh, unleaded gasoline. Minimum rating of 87 octane/87 AKI (91 RON). Up to 10% ethanol (gasohol) is acceptable. DO NOT use E85.

What fuel do Generac generators run on?

A permanently installed Generac home backup generator protects your home automatically. It runs on natural gas or liquid propane (LP) fuel, and sits outside just like a central air conditioning unit.