What Size Standby Generator Do I Need For My Home?

When a power outage occurs, it becomes clear how necessary a standby generator is in an emergency. Everyone needs power to run their home and live safely. However, different homes with different uses require different levels of power.
Let’s take a moment to consider key questions and understandings to determine what standby generator you need for your home, and how Dauenhauer can help you choose the right size.
Table of Contents
Why Your Generator Size Is Important
Choosing the best house generator size ensures efficiency, safety, and cost-effectiveness. A generator that is too small will be unable to power your home adequately, and a generator that is too big will incur unnecessary waste and costs.
Here are just some of the key reasons why picking the right-sized generator is important:
- Essential appliances and systems can run smoothly.
- Prevent the generator from overloading, overheating, and failing.
- Save money over time by avoiding electrical repairs.
- Extend the lifespan of the main generator and connected devices.
Factors That Determine What Size Generator You Need
To better understand the size of the generator you need, consider the time you spend in your home, its size, and the amount of energy you use when inside.
Square Footage of Your Home
Measure the square footage of your home first to determine the size generator you will need. If the generator is too small, you will most likely encounter system failure, possibly requiring a new electrical installation. If the generator is too big, you will end up using more energy and money.
If you live in a disaster-prone area with frequent storms, it is also a good idea to have a standby or backup generator.
Essential Appliances & Systems to Power
Make a list of essential appliances you will need in case of a power outage. Knowing what appliances require how much wattage helps you better understand the amount of power necessary for your home generator.
This list can include things like your:
- Refrigerator
- Central Air Conditioner
- Microwave
- Sump Pump
- Medical Equipment
If you are unsure of your appliance’s wattage, use this formula to find out:
Wattage (W) = Voltage (V) x Amperage (A)
Starting Wattage vs Running Wattage
Get a generator that is capable of handling the total of the starting wattage and running wattage of your appliances.
The starting wattage, or surge power, refers to the initial amount of power required to start the appliance.
The running wattage, or continuous power, refers to the amount of power required to keep the appliance operational.
An example of this is your refrigerator, which has a starting wattage of approximately 700 watts and a running wattage of around 2,200 watts.
Tip: Both wattages can usually be found on the appliance’s nameplate or rating plate.
How to Estimate the Right Generator Size
Once you have measured your home and made a list of all the necessary appliances, their starting wattage, and their running wattage, it is time to calculate the right whole-house generator size.
- Add the total starting wattages and the total running wattages.
- Increase the total wattage by 20-25% to give room for future growth.
- Then choose a portable or standby generator based on your wattage needs.
Generator power = total wattage x 1.25

Common Types of Generators and Their Capacity Ranges
Did you know that different types of generators are designed for various lifestyles and power requirements? Here are a few of the most common types of generators.
- Portable Generators are great for small, short-term power needs, such as camping and powering construction tools.
- Inverter Generators are also ideal for smaller needs, such as camping, charging laptops, and powering sensitive electronics.
- Standby (Whole-House) Generators are ideal for providing backup power to your home during power surges.
- Commercial and industrial generators are designed for use in commercial buildings, such as business offices, high-rise buildings, and shopping centers.
Another way to determine which generator is best for you is to consider your wattage range.
- 1 kW to 10 kW: Generally, something small, like a portable generator, is your best option.
- 10 kW to 50 kW: While still on the smaller side, a generator with this level of power is best if you are running heavy electric appliances, like a refrigerator or washing machine. This is typically how much a home generator produces.
- 50 kW to 100 kW: These generators are an excellent choice for offices and restaurants.
- 100 kW to 200 kW: This power level is suitable for a whole office or apartment building.
- 200 kW to 300+ kW: These are the best choices for when you need continuous electrical maintenance, such as in a high-rise building.
When to Choose a Whole-House Generator
While some people may not need a backup power supply, others should have a whole-house generator. This way, you can continue to power important (and even life-saving) devices through any outage.
Turn to Dauenhauer, and we’ll help you choose the right-sized whole-house generator for your property and needs.
Contact Dauenhauer for Your Standby Generator
Dauenhauer understands that every home and building has unique needs and preferences for making it feel safe and comfortable, especially during disasters. Give us a call, and we will work with you to calculate your wattage and provide the best generator for your situation.
FAQs
What size generator do I need for my house?
For essentials, a generator with about 5,000 – 7,500 watts is sufficient. If you want to power your entire house, you will need a generator with approximately 20,000 watts.
What size generator do I need to run a refrigerator
While a refrigerator requires about 2,200 watts, you will likely want a generator with at least 3,000 watts to power more than just your refrigerator.
Can I use a portable generator for my whole house?
You can certainly try, but you will need a whole-house generator. Portable generators simply do not produce enough power to operate a house.
What type of fuel do whole-home generators use?
A whole-home generator should come with details about the specific type of fuel required. Generally, generators run on gasoline, propane, or natural gas.