Whole House Generators (Calculate Your Power Needs) How-To Guide 2026

A whole house generator is a great way to make sure you have a reliable source of backup power. They can be your saving grace during natural disasters or power outages. Electricity is important for everyday life. That is why it is important to choose the right whole house generators for you.  

How Big of a Generator Do I Need to Run My Entire House?

Different households have different power requirements depending on your everyday lifestyle. There are many different ways to calculate and estimate the power requirement of your home. However, a general rule of thumb is that for an average household, a 7500 watt generator should do the job. Typically, this is enough to power basic and necessary appliances such as a refrigerator, freezer, water heater, and lights. Bigger households that use more power will require a bigger unit that gives out more watts. For this, you can opt for a 9000 watt, 10000 watt, or even a 12000 watt generator. These are also great options for smaller houses that want full access to power in the event of a power outage because a bigger unit will last longer when putting out continuous backup power for your home.

How to Calculate How Many Watts You need

To calculate how many watts you need to run your home, list all your devices, prepare a calculator, and follow these steps:

Step 1:

Identify which appliances are most needed during an outage. Usually, this includes air conditioning, refrigerator, and an additional source of backup power.

Step 2:

After you have identified your appliances, identify their watt requirements. You will then be able to calculate starting and running watt requirements.

Step 3: Purchasing Your Generator

After calculating your start and run times, buy one based on your personal power needs. It is recommended to choose one  that can sustain a larger power requirement.

Starting Watts Vs. Running Watts

Some appliances require more power the first time they are used. This is known as starting watts. The actual watts after a few seconds is called the running watts. Running watts are sustained until the device has been powered off.

Choosing a Generator for Your Home

There are a few things to consider before determining what size is best for you. You will want to consider the appliances you want to power, their power requirement.

• Lights: 60 Watt – 600 Watt
• Refrigerator: 600 Watts
• Computers: 60 Watt – 300 Watt
• Heater: 1,500 Watt
• Air Conditioner: 1,800 Watt
• Fuel type (if applicable) – natural gas or alternative

Installation and Costs

The rule of thumb is to choose larger than your actual power requirement. For example, if you need 1,700 watts to run your home, purchase one that can produce 2,000 watts. Installing a unit for your home can get expensive. While you can opt to do this job yourself, most companies such as advise against doing so. If you are inexperienced and have not taken on a job like this before, it is best to hire a contractor to install to make sure everything runs smoothly.

Maintenance Costs

Once a power generator has undergone proper installation, it is important to make sure that it’s being maintained properly to ensure that it works in the event of an emergency. Some things you can do to properly maintain the condition of your home generator is making sure it is in a dry open space to prevent any fire hazards or overheating. The type of fuel your unit runs on can also affect maintenance costs. They can operate on either diesel, gasoline, natural gas, or propane. Generally, gasoline is more expensive than diesel. There are also fuel efficient units that can take the different types of fuel so you can choose at your convenience.

Frequently asked Questions

Below are the answers to some of the most frequently asked questions.

Are generators noisy?

Most make up to 65 to 100 decibels of noise.

Do you need a permit to install a power generator?

Generally, your contractor would have to ask permission from the local authorities.

Can a generator power your entire home?

If you buy one based on your power requirement, there should be no problem powering the entire household.

Will a 7500 watt generator run my house?

Yes, it is capable of running your most used appliances in your household.

Do you have to turn off your main breaker when using a generator?

It is a good idea to turn off the main breaker and transfer switch to prevent a power surge.  Many come with warranties and customer service numbers to assist you if you need help.

Final Thoughts: Are Whole House Generators Worth It?

Whole house generators are great for powering your home in the case of an emergency, power outage or natural disaster. In places where outages are common, many also opt for home standby unit or a backup unit in their home. Remember, whether or not you live in an area prone to outages, it is always a good idea to have a standby unit for backup power. The most important aspect to take into consideration before you buy a home generator, are your items and their power needs. A whole house generator does not necessarily mean buying an expensive unit to power every corner of your home. It can be as simple as investing in a unit strong enough to power the necessities. Calculating your total power requirement is the best way to choose the right sized generator for you.