Royse City, Tx.
Mon-Fri 08:00 AM - 06:00 PM
When the power goes out in North Texas, the question gets real fast: what size generator for house backup actually makes sense for your home? Too small, and you are juggling breakers and losing comfort. Too large, and you are paying for capacity you may never use. The right answer comes down to what you need to run, how your home is wired, and whether you want basic survival power or whole-home coverage.
A lot of homeowners start with the square footage of the house. That can help a little, but it is not the deciding factor. Generator sizing is really about electrical load. A 1,600-square-foot home with two air conditioners, an electric water heater, and a well pump may need more backup power than a larger home with gas appliances and lower overall demand.
The first thing to figure out is your goal during an outage. Some families want to keep the refrigerator cold, a few lights on, phones charged, and maybe the internet running. Others want the house to feel almost normal, including air conditioning, kitchen circuits, laundry, and larger appliances. Those are two very different generator sizes.
For essential circuits only, many homes land somewhere in the 5,000 to 10,000 watt range if using a portable setup. That may cover the refrigerator, freezer, lights, garage door opener, television, outlets for charging, and possibly a microwave. If you want central air conditioning, the number climbs quickly. Whole-home standby systems often start around 14kW and can go well past 24kW depending on the house.
That is why the best sizing process starts with a load calculation, not a guess.
Think in terms of must-have loads first. In most homes, that includes refrigeration, some lighting, internet equipment, device charging, and at least a few general-use outlets. Then consider comfort and safety items like a sump pump, medical equipment, security system, garage door opener, or well pump.
Next comes heating and cooling. In the DFW area, air conditioning is often the biggest factor. If the outage happens during a Texas heat wave, many homeowners do not want to go without AC for long. But AC equipment has both running watts and startup watts. That startup surge can be much higher, and your generator needs to handle it.
Electric cooking, electric dryers, and electric water heaters also add serious load. You may not need all of them during an outage, and deciding what to leave off can save thousands on the generator system.
This is where sizing mistakes happen. Some equipment uses a steady amount of power once it is operating. That is the running wattage. Motors and compressors, though, often need a larger burst to start. That is the startup wattage.
Your refrigerator may run on a modest amount of power once it is on, but the compressor draws more at startup. The same goes for an air conditioner, furnace blower, well pump, and some freezers. If you only add up running watts, you can end up with a generator that looks fine on paper but struggles in real use.
For many Texas homes, HVAC is the load that determines the generator size. A gas furnace does not use much electricity compared with central AC, because you are mostly powering the blower and controls. A central air conditioner is a different story.
A smaller home with one modest AC unit may work well with a mid-size standby generator if the rest of the house is managed carefully. A larger home with multiple systems may need load management, selective circuit backup, or a larger whole-home unit. There is no honest one-size-fits-all answer here.
If you want a rough planning guide, here is how many homes break down.
A portable generator in the 5kW to 7.5kW range often supports basics only. Think refrigerator, freezer, lights, fans, device charging, television, and a few outlets. It usually will not run the whole house, and it may not support central AC.
A portable or small standby generator in the 8kW to 12kW range can often handle more essentials and, in some cases, smaller HVAC loads or selected circuits. This range works best when the home has gas heat, gas water heating, or other lower electrical demands.
A standby generator in the 14kW to 18kW range is where many homeowners start if they want stronger coverage for a typical house. This may support most essentials plus one central AC system in the right setup.
A 20kW to 26kW standby generator is common for larger homes, homes with heavier electric loads, or families who want near-whole-home backup. If you have two AC systems, major kitchen loads, or a larger service, this range may be more realistic.
These are still broad ranges, not a substitute for an actual load calculation.
This question matters because it affects both sizing and convenience. A portable generator can be a practical option for short outages and basic needs. It costs less up front, but it requires manual setup, fueling, safe placement outdoors, and a proper transfer switch or interlock installation. It is not something you want to scramble with in bad weather if you can avoid it.
A standby generator is permanently installed, connected to fuel, and designed to start automatically when utility power drops. It is the better fit for homeowners who want dependable backup without dragging out extension cords or making fast decisions in the dark. It also makes more sense for families with medical needs, home offices, or longer outage concerns.
Sizing tends to be more precise with standby systems because they are usually integrated into the home’s electrical system through an automatic transfer switch and planned load coverage.
One of the biggest misconceptions is that generator sizing is only about the unit outside. In reality, your electrical panel, transfer equipment, and circuit layout matter just as much. An older panel may not be ideal for a generator connection. Some homes benefit from separating essential loads from non-essential loads. Others need a panel upgrade before a backup power system can be installed safely and cleanly.
This is one reason a professional evaluation matters. Good generator planning is not about selling the biggest unit on the lot. It is about matching the system to the house so it performs the way you expect when the lights go out.
The most common mistake is planning by square footage alone. It is easy, but it is often wrong. Another is forgetting startup loads, especially for air conditioning and pumps. A third is assuming every appliance needs to run at once. In many homes, smart load management makes a smaller generator a better value.
Fuel type also gets overlooked. Natural gas, propane, and gasoline each affect runtime, maintenance, and output. Standby units connected to natural gas are convenient, but the available gas service and generator specs still need to line up properly. Propane can be a strong choice too, but tank size matters for longer outages.
And finally, do not rely on extension cords as a long-term backup plan. Safe generator use requires proper transfer equipment so power does not backfeed into utility lines or create hazards inside the home.
If your goal is basic outage survival, a smaller generator may be all you need. If your goal is to keep the house comfortable, protect food and electronics, maintain business continuity, and avoid major disruption, you are likely looking at a standby system with enough capacity for your essential circuits and at least part of your HVAC load.
For many DFW homeowners, the sweet spot ends up somewhere between essential-circuit backup and full whole-home power. That means choosing a generator large enough to carry the circuits that matter most, while using load management to avoid paying for unnecessary capacity. It is a practical middle ground, and often the smartest one.
At NextGen Electric, that is the kind of approach that makes sense – size it honestly, install it safely, and make sure it works the way your family expects when utility power fails.
The best next step is not guessing from a chart. It is getting a real load assessment based on your panel, your HVAC equipment, your major appliances, and how you actually live in the house. A generator should bring peace of mind, not another problem to troubleshoot when the storm rolls in.
Wondering what size generator for house backup? Learn how to size by w
Learn the difference between commercial and industrial electricity, fr
