Do You Need a Standby Generator? Purchase and Installation Guide

Two electricians installing an outdoor generator

Do you need a generator?

Losing power to your house or business can be more than inconvenient. Losing power to your refrigerator and freezer can cost you hundreds of lost food. A blackout that cuts power to your air conditioner or heater during extremely hot or cold weather can be hazardous to the health of your family, pets, staff, or clients.  

Some homes and businesses house medical equipment and computer programs that are dependent on the continuous power supply. For these homes and businesses, a loss of power can be devastating. Can you afford to be without power? 

A standby generator is a stationary fuel-powered engine that provides emergency power to your essential appliances–such as your refrigerator and lights–during a power outage.

In this blog, we answer your questions about different types of standby generators, installation, cost, maintenance, and more.  

Why is a standby generator better than a portable generator? 

Most people are familiar with portable generators, which are gas-powered units that have a short run-time, low load expectation, and a low cost. A portable generator must be manually filled or connected to fuel, started, and connected to an electric supply during a power outage. 

A standby generator is a professionally installed permanently connected stationary unit that will start automatically (or with the push of a button) during a blackout. Standby generators run continuously for long periods of time. In addition to the comfort and security, 

installing a standby generator can increase property value by 3-5%.

What kind of standby generator should I buy? 

Propane or Natural Gas vs. Diesel

Standby generators are most typically powered by natural gas or propane. Dual standby generators can be powered by either propane or natural gas. 

Commercial generators can be bi-fuel, which means they can be powered by both propane and natural gas. Diesel-powered industrial generators provide emergency power to large facilities like office buildings, airports, medical facilities, and hospitals.

Electrician working on outdoor electric box

Do I need to worry about exhaust/emissions?

Generator exhaust can contain VOCs, hydrocarbons, sulfur dioxide, carbon dioxide, carbon monoxide, and nitrogen dioxide. Because they are considered engines that impact the environment and public health, they are subject to EPA regulations. 

EPA regulations are much less strict over clean-burning natural gas (NG) and propane (LP) home generators than diesel or industrial generators which are heavily polluting. Manufacturers of industrial generators over 80 kW are required to install a catalyst device in the exhaust to control harmful emissions. Depending on the size/type of generator you purchase and your local environmental regulations, you may also need to file an air permit, which your installer can do for you.

Air-cooled vs. liquid-cooled

Most home generators–under 22 kWh–are air-cooled. This simply means they cycle the surrounding air to keep the engine cool. 

Standby generators that are 22 kWh or larger are used in commercial or industrial settings and are liquid-cooled. Liquid-cooled generators use water, coolant, or hydrogen to prevent overheating.

What size generator do you need?

Perhaps the most important consideration when shopping for a standby generator is the size. Home generators are typically air-cooled and range in size from 5 kW to 25 kW. Commercial or industrial generators are typically liquid-cooled and start at 25 kW. Unlike a solar array, the size generator you buy is not determined by your average power consumption. It’s determined by the power consumption of your essential appliances. For example, a 5 kW generator can power a few lights, a sump pump, a refrigerator, and a heater fan, whereas a 25 kW generator can power a mid-sized home or small business, including the air conditioner. 

To determine the size generator that you need, you should make a list of the appliances you need to run during a blackout. You will need to know the starting watts and running watts required for each of these appliances. The total power requirements of the appliances you will be powering are called the load. 

Where to find the watts your appliance requires 

The power used to run your appliance can be found on the rating label on the inside or back of your appliance. To calculate the required running wattage, multiply the volts (V) by the amps (A). For example, a 115V 6A refrigerator requires 690 watts to run.

An appliance with a motor uses more power to start than it uses to run. If starting amps aren’t listed on the rating label, they should be listed on the sticker on or next to the motor. In some cases, you will have to move your appliance (like a refrigerator) to see this sticker.

If you can’t find the starting wattage of an appliance, appliances generally require 2-3 times the watts to start. So a 115V 6A refrigerator may require a surge of 2,070 watts to start. 

A refrigerator that uses 2,070 starting watts and 690 running watts would require a generator that has at least 2,070 starting watts and 690 running watts. 

Because running a generator at full capacity will shorten its lifespan, it’s best to choose a generator that is slightly bigger than your power load. 

  1. List the appliances you want to power with your generator
  2. Calculate the running AND starting watts required by each appliance
  3. Buy a generator slightly bigger than your load

Why you should get shed loading or load management 

You can get more coverage from a smaller generator with load-shedding and load management. 

During an outage, if every connected appliance starts up when your generator kicks on, it will be overloaded. Generators with load management send power to the highest priority appliances with the highest starting wattage first. Additional loads are added as more power becomes available. To prevent overload, the generator turns off or ‘sheds’ non-essential electric loads as it nears maximum capacity. Load shedding allows priority loads to stay on. As more power comes available, load management allows discarded loads to be powered back on. 

Will your generator be noisy?

Because generators are known to be noisy, noise may be an additional consideration when you choose a generator. They can emit 65 to 100 decibels (db). 70 dB of continuous noise can damage hearing. To help you understand, a lawnmower is 65 dB and a jet engine is 100 dB at take off. 

Can I reduce generator noise?

Because of this, many home and commercial models come in a noise-reducing enclosure. Noise can be further reduced by buying a quiet model such as a Generac Guardian. A concrete wall can reduce the sound of your generator past your property line, and ease any neighborly tensions caused by installing a generator. 

Why you need an automatic transfer switch

By law, if you install a standby generator you must install a transfer switch. A transfer switch disconnects the utility or the generator when the electric load needs to be switched from one to the other.

generac transfer switch

Electric code requires the use of a transfer switch with a standby generator to prevent electrical fires, injury, and loss of equipment. 

An automatic transfer switch monitors incoming power from your utility. In the event of an outage, it tells the generator to start. Once the generator is running, it transfers the electric load from the utility to the generator. The automatic transfer switch continues to monitor the utility line. When it detects a stable power supply from the utility, it transfers the electric load from the generator to the utility while the generator cools down. All this takes place whether or not the homeowner or business operator is present.

With a manual switch, someone must be present to switch the electric load from the utility to the generator and back again. The homeowner or business operator would then manage the power load by powering on or off appliances at the transfer switch. 

Why you should get remote monitoring?

Many generators come with WiFi and remote monitoring for 24/7 access to your generator from a computer or mobile device. With remote monitoring, you will know when your generator runs and when it needs service. You can also see your generator’s status, running history, service history, and maintenance requirements. You will receive notifications by text or email if your generator’s status changes. The remote monitoring system can be accessed by users, technicians, and monitoring services. A generator monitoring system can be added to generators that don’t come with remote monitoring. 

What maintenance will your standby generator require?

No matter what generator you choose, you will need to maintain it. A generator is an engine that requires routine maintenance, service, and inspection. This includes checking and changing the oil, coolant, and battery fluids, air filter, fuel filter, oil filter, and spark plugs, inspecting and replacing the wiring, belts, hoses, and exhaust system as necessary. But don’t be overwhelmed. Your electrician can maintain and service your generator. 

What is the life expectancy and warranty on a standby generator?

A well-maintained generator has a life expectancy of 3,000 hours or 30 years. Warranties for standby generators are generally 3-5 years. 

How much does a standby generator cost?

Now that you understand what to look for in a standby generator, let’s discuss the cost. Depending on the size of generator you purchase, a home generator can cost anywhere from $2,000 to $20,000. The average cost of a home generator is around $4,500. 

Commercial generators start around $5,000 and can run into the hundreds of thousands depending on your needs. The average cost for a commercial generator is around $20,000. 

But what does installation cost?

The cost of installing a generator varies depending on the size and type of generator, site preparation, access to connections, necessary permits, and more. While many factors affect the cost of installation, you can roughly estimate it as equal to the cost of the equipment. 

How are standby generators installed?

Once the site is prepared, it generally takes an electrician a day or two to physically install and connect the equipment. However, there are more steps involved than just the installation of the physical equipment. Obtaining the necessary permits can take anywhere from hours to weeks. Your installer will hire subcontractors to prepare the site: install or extend your gas line, dig a trench to the gas line, level the site, and pour a concrete pad. He must install wiring and a sub-panel and reconfigure your electric service. After the unit is physically connected to gas and electricity, it must pass utility and/or city inspection. Your installer should make all these arrangements.

Below is a checklist of steps for installation

    1. Choose generator
    2. Hire installer
    3. Choose location
      • Code Compliant
        • 18 inches from the building
        • 5 feet from any windows, doors, vents
        • 10 feet from flammable materials
        • 4 feet clearance above
        • 3 feet clearance at front and sides
      • Near fuel and electric
      • Accessible
    4. Obtain permits
    5. Prepare the site
    6. Set the equipment
    7. Connect gas lines and electricity
    8. Inspect

Can you install your own standby generator?

In this day and age of DIY videos, there is an abundance of information to help you install your own standby generator. Don’t do it. Improper installation can lead to:

  • Injury or death from electric shock 
  • Carbon monoxide poisoning or death 
  • Fire at the generator or in the home
  • Damaged appliances
  • Failed city and/or utility inspection that prevents power from being restored to your home or business
  • An overloaded generator that can’t power the appliances to which it’s connected
  • Inefficient fuel burning

Hire a licensed electrician.

Ready to install a generator? 

Two electricians walking out of home

When it’s time to purchase a standby generator for your home or business, choose Redline Electric & Solar. We are a licensed, bonded, and insured electrical contracting business and a Generac-approved dealer and installer. 

Do you have questions we haven’t answered? Contact a Redline Electric & Solar representative at and we’ll be happy to help. 

NABCEP certified Redline Electric & Solar is the best choice for your electrical and solar needs in Arizona. We are a family-owned and operated electrical contracting business, with over 60 years of combined experience. We pride ourselves in our honesty, integrity, and high-quality work, with 100% satisfaction guaranteed to our customers. When you choose Redline Electric and Solar, you can have peace of mind and be confident that you made the right decision.