What Size Generator Do You Need for Your Texas Home?

A Practical Sizing Guide

When the power goes out in Texas, most homeowners are not thinking about generator specifications. They are thinking about keeping the air conditioner running, the refrigerator cold, the lights on, and their family comfortable.

That makes choosing the right generator size important. A generator that is too small may not handle the appliances and systems you want to power. Going unnecessarily large can mean paying for more generator capacity than your home actually needs.

So, what size generator do you need for your Texas home?

The answer depends less on the square footage of your house and more on what you want to keep running during an outage. Generac recommends sizing a standby generator based on electrical load, including both the running and starting wattage of the appliances and systems you want to power.

At SouthTex Propane, generator sizing is part of the consultation process. The team uses advanced software to evaluate a home’s specific power needs before recommending a Generac system.

Generator Size Is Measured in Kilowatts

Whole-home standby generators are typically rated in kilowatts, or kW. One kilowatt equals 1,000 watts of electrical power.

Generac’s current air-cooled home standby generator lineup ranges from 10 kW to 28 kW, giving homeowners several options depending on their electrical needs.

But bigger is not automatically better.

The goal is to choose enough capacity to handle your home’s expected electrical load without paying for substantially more generator than you need. Two homes with the same square footage can require very different generator sizes depending on their HVAC systems, appliances, water source, and how the homeowners plan to use electricity during an outage.

Why Square Footage Alone Doesn’t Tell You the Right Generator Size

You may see recommendations online such as “a 2,000-square-foot home needs a 20 kW generator.”

That can be a helpful starting point, but it is not enough information to properly size a generator.

Imagine two 2,000-square-foot Texas homes. One has propane heat, propane cooking, city water, and a single central air-conditioning system. The other has an electric heat pump, electric range, well pump, electric dryer, pool equipment, and an EV charger.

The houses may be exactly the same size, but their electrical demands during an outage could be completely different.

Generac specifically advises homeowners to consider electrical loads rather than relying on square footage alone.

A Practical Generator Sizing Starting Point

While every home should be evaluated individually, Generac provides several examples that can give homeowners a general idea of what different generator sizes may handle.

For a home around 1,550 square feet with gas heat, Generac notes that a 10 kW to 14 kW generator may be sufficient when paired with load management. Homes with an electric heat pump, well pump, or other high-demand equipment may need to move closer to 18 kW.

For a home around 2,000 square feet, Generac identifies 18 kW to 22 kW as a common range for homeowners looking for greater whole-home comfort.

These numbers should be treated as planning examples rather than guarantees. The actual generator required for your home depends on your appliances, HVAC equipment, electrical panel, starting loads, and the level of backup power you expect.

That is why SouthTex Propane evaluates each home individually rather than recommending generator size based on square footage alone. SouthTex’s generator service includes consultation, installation, setup, and customer education as part of its turnkey approach.

Start by Deciding What You Want to Power

One of the easiest ways to begin sizing your generator is to think about what life should look like during an outage.

Do you only want to keep the essentials running, or do you want your home to operate almost normally?

For some homeowners, the priority may be the refrigerator, freezer, lights, internet, and a few outlets. For others, backup power means keeping the central A/C running, using kitchen appliances, operating a well pump, and continuing to use the home much as they normally would.

Generac separates household loads into general categories ranging from essentials such as refrigeration and lighting to higher-demand equipment such as central air conditioning, electric ranges, well pumps, dryers, and EV chargers.

For a Texas homeowner, air conditioning is especially important to include in the sizing conversation. Central HVAC equipment can represent one of the larger electrical demands on a home’s generator.

Running Watts and Starting Watts Both Matter

One reason generator sizing can get complicated is that some appliances require more electricity when they first turn on than they need once they are running.

This is known as starting wattage, or surge wattage.

Equipment with motors, such as central air conditioners, refrigerators, sump pumps, and well pumps, can require a temporary surge of electricity when they start. Generac recommends accounting for both running wattage and starting wattage when determining generator capacity.

For example, Generac notes that the basic calculation is the total running wattage of the equipment you want powered plus the largest applicable starting surge. Because determining those numbers accurately requires appliance-specific information, Generac recommends a professional site evaluation.

Don’t Forget About Your Air Conditioner

In Texas, this is a big one.

A generator may technically be able to power your lights, refrigerator, televisions, and outlets while still struggling when the central air conditioner starts.

According to Generac’s current sizing guidance, a 3-ton central air-conditioning unit may use roughly 3.5 to 5 kW while running, while starting demand can be much higher. Equipment such as load management or a compatible soft-start solution may help manage that temporary demand without automatically requiring a much larger generator.

The exact requirements depend on the HVAC system installed in your home, which is another reason an on-site load calculation is more reliable than a generator recommendation based only on house size.

What Is Load Management?

Load management can allow a homeowner to power more of the house without sizing the generator for every high-demand appliance operating at exactly the same moment.

A load management system monitors demand and temporarily delays lower-priority equipment when the generator is approaching its maximum capacity. Once capacity becomes available, that equipment can be allowed to operate again.

For example, instead of attempting to start your central A/C and electric dryer at the same moment, the system can prioritize one load and temporarily delay the other.

This can sometimes make a properly designed smaller generator a better solution than simply purchasing the largest generator available.

What Else Should Texas Homeowners Consider?

Generator sizing involves more than counting appliances.

Your home’s heating system matters. A house with propane heat may have a different electrical demand than a house using an electric heat pump.

Your water source matters. Homes outside larger cities may rely on a well pump that needs to be included in the generator calculation.

Your lifestyle matters, too. Pool equipment, home offices, medical equipment, electric cooking appliances, multiple HVAC systems, workshops, and EV chargers can all change the amount of backup power a household wants available.

Even your future plans should be considered.

If you are building a home or planning future improvements, SouthTex Propane can work with homeowners and builders during the planning process to account for future propane needs such as outdoor kitchens, pools, and other additions. Learn more about SouthTex Propane’s residential services and new-home planning.

Does a Propane Generator Affect Generator Sizing?

The electrical demand of the home is what determines how much generator capacity you need, but fuel supply is another important part of the overall system.

If your whole-home generator will operate on propane, your propane tank and fuel system need to be capable of supporting the generator along with any other propane appliances being used in the home.

Generac’s sizing tool notes that generator installations may require additional equipment or changes to the home’s fuel system, including an upgraded propane tank in some situations.

SouthTex Propane can handle both sides of the project. The team provides whole-home backup generator installation along with propane tank installation, allowing the generator and propane supply to be planned together.

What Size Generator Is Best for Your Home?

There is no single generator size that is right for every Texas home.

A smaller system with intelligent load management may be perfect for one family, while another property may need considerably more capacity because of multiple HVAC systems, electric appliances, a well, or other high-demand equipment.

The best approach is to determine:

1. What absolutely needs to stay powered.
2. What you would like to continue using for comfort.
3. Which appliances have large starting loads.
4. How much electricity those systems require together.
5. Whether load management can help balance demand.

Then, have the home professionally evaluated before choosing a specific unit.

SouthTex Propane uses advanced sizing software to determine the Generac generator best suited to a customer’s specific power needs, rather than taking a one-size-fits-all approach.

Local Generator Installation for South Central Texas

SouthTex Propane provides a turnkey generator service designed to make backup power easier for homeowners. From consultation and sizing to installation, propane setup, and customer education, the goal is to provide one local team throughout the process.

SouthTex currently serves eight counties in the greater San Antonio area, including communities throughout Bexar, Wilson, Guadalupe, Karnes, Comal, Kendall, Gonzales, and Kerr counties. View SouthTex Propane’s service areas to see current availability near your home.

If you’re considering backup power for your home, call SouthTex Propane at 210-997-8241 to discuss your generator and propane needs.

Frequently Asked Questions