What Size Generator Do You Need?

Written on: August 30, 2019

generator options connecticutFrom thunderstorms, flash floods and snowstorms to hurricanes and tornadoes, natural disasters could happen in Connecticut during any season.

Having a generator on standby — in the event of a power outage — is essential for keeping your home up and running. However, the size of generator you’ll need to purchase will depend on how you use it. 

In this article, we’ll discuss the various types of generators, how to calculate the size of generator you need for your home, and what’s required to maintain your generator so you can prolong its life expectancy. 

The Types of Generator for Your Home

There are three primary types of generators that will work to power different appliances in your home.

Portable Generator

This type of generator is most often powered by fuel (either gas or diesel). Portable generators can put off quite a bit of power. They can be used to run large appliances like televisions and refrigerators but only as a temporary fix. For prolonged power outages, you’ll need a more powerful generator to keep up.  

Even though portable generators are quite powerful, hard-wired appliances like AC units cannot be powered by a portable generator without a manual transfer switch. To add a manual transfer switch, you’ll likely need to bring in a professional.

The average cost of a portable generator is roughly $2,000​.

Inverter Generator

An inverter generator uses an engine and an alternator to create AC power. You can also use a rectifier to convert your AC power into DC power. This type of generator is usually very small, and could easily fit inside your car for convenient, portable charges. Inverter generators are best used for quick charge needs, like juicing up a car battery or giving your laptop power. It wouldn’t be the best option for powering the appliances in your home. 

The average cost of an inverter generator is roughly $300​.

Standby Generator

Also known as a whole-house standby generator, a standby generator can operate off of liquid propane or natural gas and will automatically transfer electric command during power loss.

Standby generators are best used for emergency backup when you need your home at peak performance. They are also great for prolonged blackouts, where you need a backup source of energy for more than just a few hours. Commercially, hospitals have standby generators on deck to ensure their machinery will function in the event of an emergency. 

The average cost of a standby generator is roughly $3,000​.

Portable Generator vs. Standby Generator for Your Home

Which is better for a backup power source: a portable generator or standby generator? 

As the name implies, portables generators are great because you can take them anywhere. You can easily take them with you to power an RV on a quick weekend getaway, or bring onto your boat for a day of fun. They also carry enough of a charge to energize your home for a while, if needed. 

However, if you think your home will need power for more than just a few hours, a standby generator is best for you. Keeping a portable generator running for long periods of time requires a lot of fuel. And, as noted above, it requires help from a professional to add a manual transfer switch if you need air conditioning or heat, which can add to the cost of a portable charger. 

Calculating Watts to Generator Sizing

Regardless of the type of generator you select, you’ll need to find the appropriate size to fit your energy needs. Generators are sized based on their electrical output, which is usually measured in watts.  

The three varieties of generators range in size from 700 watts to 18,000 watts (the latter size is used for commercial, job-site needs). 

The best way to pick your appropriate generator is to determine which appliances you’ll connect to it. Then, simply add the wattage of each device to know how much power your generator needs. 

Here’s a quick chart to show what size generator you need for your house based on the average watt calculations for common household appliances:



AC central 3500
Coffee maker (2 cups) 600
Microwave 1800
Electric Range (medium size)  1800
Freezer 65
Refrigerator (large) 780
Living Room Lights 60
Television (new technology)  80
Gas Washer 850
Gas Dryer 3400
Garage Door 1000

What Size Generator Do I Need for My Home?

Let’s put the following data into a real situation. If the power goes at your home, maybe you’ll need a generator to power the following: 

AC unit (3500W) + Living room lights (60W)+ Television (80W) + Refrigerator (780W) = 4,420W

To provide energy to these four appliances, you’ll need a generator that can handle at least 4,420W. 

If you’re a light energy user, maybe you’ll only need to power a few appliances:

Coffee maker (600W) + refrigerator (780W) = 1,380W

If this scenario sounds more like you, then you can get by with a smaller generator (maybe even a portable option) that puts out 1,380W. 

Most homeowners, however, will use a generator somewhere between 3,000 and 6,500 watts.

You might also consider how prone your home is to power outages. If you live in an area extra susceptible to power loss, you should be more conservative with your estimate. That way, you can ensure you’re protected in the event of a prolonged power outage. 

For a customized assessment, contact a professional.

The Correct Generator Size for Your House is Really Important

Sizing your generator should not be taken lightly. 

If you choose a generator that is too small, your essential appliances will not work during a power outage. Overloading your generator with appliances that require more energy than your generator can provide will break your generator. Worse still, overloading your generator can also damage the devices connected to it. 

On the other hand, if you choose a generator that is too big, you might be wasting your money. Excessively large generators cost more to purchase and to install and fuel. 

Maintaining Your Generator, so It Works When You Need It

Like all systems in your home, annual maintenance for your generator is recommended. By giving your generator a little TLC, you can ensure that it will function properly when you need it most. 

To give your generator a proper check-up, consider the following tips:

If you need help maintaining your generator’s health, make sure to contact an expert.