What Size Generator Do I Need for My Southlake Home?

Generator size is measured in kilowatts (kW). It depends on your home's electrical load, not its square footage.

General ranges:

• Essential circuits only — lower kW range. Fridge, lights, outlets, one system.
• Mid-sized homes with central air — mid kW range.
• Larger homes or two HVAC systems — upper kW range.

To size yours:

• List every appliance you want running during an outage
• Add up the running wattage on each one
• Add starting wattage for AC, pumps, and refrigerators
• Add a safety margin, then convert the total to kilowatts

Step three is where most estimates fail. Those units pull far more power the moment they kick on. A professional load calculation is the only way to get a real number.

Generator capacity is measured in kilowatts, or kW. That number tells you how much power the unit can supply at once. It does not tell you anything about your floor plan.

Square footage feels like the right starting point. It is not. It is a rough stand-in for something else, and a poor one.

Here is the difference:

• Square footage tells you how big the house is
• Load tells you how much power runs at the same time

Those are not the same thing. One home may run a single system and a gas water heater. Another the same size runs two AC systems and an electric water heater. The second home needs a much larger unit.

Air conditioning is usually what settles it. In Southlake, that means counting your systems before anything else.

So square footage is out. Load is in. Here is what that looks like in kilowatts.

These ranges give you a starting point. They are not your answer.

Where you land depends on what you want running during an outage. Backing up the essentials asks far less of a unit than backing up everything.

Most Southlake homes we size fall in the upper half of that table. Larger floor plans and second HVAC systems push the number up quickly.

Do not treat these ranges as a decision. Treat them as a sanity check. If someone quotes you a size far outside the range for your coverage level, ask why.

Your real number comes from adding up what your home actually pulls. That is next.

This is the part that gives you a real number. It takes some time, but the method is simple.

Follow these five steps:

1. List what you want powered — Write down every appliance and system you need during an outage.

2. Find the running wattage — Check the label on each unit, or the owner's manual. The U.S. Department of Energy publishes appliance wattage estimates you can use as a starting point.

3. Add the starting wattage — Air conditioners, pool pumps, and refrigerators pull a large spike when they kick on. This is where most estimates break down. Running wattage is printed and easy to find. Starting wattage often is not, and it can dwarf the running number.

4. Add a safety margin — You do not want the generator running at its ceiling.

5. Convert to kilowatts — Divide your total watts by 1,000.

Miss the startup spike, and your generator will not start your AC. You find that out during the outage.

This choice drives your generator size more than anything else. Decide it before you shop.

Essential circuits cover:

• Refrigerator
• Lights and outlets
• One HVAC system
• Sump pump

Whole-home coverage adds:

• Both AC systems
• Electric water heater
• Kitchen appliances
• Laundry

Essential circuits let you get by. Whole-home coverage lets you live normally. The gap between them shows up directly in the size of the unit you need.

There is a middle path. Load management sheds non-critical circuits when demand spikes. That lets a smaller generator cover more of your home than it otherwise could. It also stretches your fuel during a long outage.

Many Southlake homeowners land there. They back up the essentials, plus the comfort items that matter most to them. It is a practical choice, not a compromise.

Think about which one you want before someone quotes you a size. The answer changes the number.

Homes here are often large. Many run two HVAC systems, not one. That single fact reshapes the load calculation.

What drives the number up in Southlake:

• Two AC systems — They dominate the total, especially when both start together.
• Pool equipment — Pumps add a steady draw and a startup spike.
• Electric water heaters — These pull hard and pull often.
• Double ovens and large kitchens — Common in newer builds here.

We size generators across Timarron, Sterling Creek, Carillon, and the Carroll ISD area. The pattern holds. Larger homes with a second system almost always need more capacity than owners expect.

Panel capacity varies too. Older Southlake homes and newer builds do not carry the same electrical service. That affects what a generator can safely tie into.

Our Berkeys Southlake team also serves Trophy Club, Grapevine, Colleyville, Keller, Westlake, and Roanoke. The load drivers look much the same across all of them.

Both directions hurt you. They just hurt you differently.

Undersized:

• The unit strains under a load it cannot carry
• It may trip or shut down when your AC kicks on
• Major appliances may not start at all
• You discover the problem during the outage, not before it

Oversized:

• You burn fuel you did not need to burn
• You paid for capacity that never gets used
• The unit runs less efficiently at light loads

The startup surge is the usual failure point. A unit sized only for running wattage will not carry your air conditioning.

Your panel matters too. Older panels sometimes need work before a generator can tie in safely. That is a condition check, not a guess.

Southlake requires permits and inspection on this work. We handle that as part of the install.

We founded this company in Southlake in 1975. Our licensed electricians size, install, and service whole-home generators here every week. We run the load calculation, check your panel, and match a unit to your home. We answer calls 24/7.

Call (817) 481-5869 for a free generator consultation.

Business Address: 1070 S Kimball Ave Suite 131, Southlake, TX 76092

Business Address: 1070 S Kimball Ave, Suite 131, Southlake, TX 76092
 Phone: (817) 481-5869
 Hours: Monday - Sunday, 7 days a week with 24/7 emergency service

Licensed, Bonded & Insured
 Texas Electrical License: TECL695440
 A+ BBB Rating Since 1997