Dallas–Fort Worth · Sizing guide 2026
How much home battery do you need? A DFW sizing guide (2026)
The short answer
It depends entirely on what you back up and for how long. If you only need to keep a refrigerator, a few lights, and your Wi‑Fi running for a few hours, a single home battery unit may be enough. If you want to run central air conditioning in a Texas summer for a full day, you’re almost certainly looking at multiple units and a carefully managed backup panel. There is no one-size-fits-all number — a proper load calculation by a licensed installer is the only way to get an accurate answer.
The 4‑step sizing method (teach this, don’t guess)
The soundest approach uses real consumption, not a magic square‑footage formula. Work through these four steps, then let an installer verify everything.
- List the circuits and appliances you must keep running.
Decide what “essential” means to you — refrigerator, freezer, lights, internet, medical devices, and possibly a window AC or mini‑split. Be honest about what you can live without during an outage. - Estimate daily energy use (kWh/day) for those loads.
For each item, roughly multiply running watts by hours you’d use it per day. A refrigerator might use a few kWh per day; lights and electronics typically add only a modest amount. Central air conditioning dwarfs everything else. - Decide how many hours (or days) of backup you want.
A short evening outage requires far less energy than a multi‑day grid failure. Also consider whether you’ll have solar to recharge during the day (more on that later). - Match the total usable kWh you need to real‑world battery capacity.
A typical residential battery unit today stores roughly 10–16 kWh of usable energy (check the current datasheet — models vary). But you can’t use every watt‑hour on paper: inverter power limits, appliance startup surges, depth of discharge, temperature extremes, and conversion losses all reduce what’s actually available. An installer will apply these factors.
What loads drive battery size? (Illustrative estimates)
The table below gives a very rough sense of how different loads compare. Every figure is approximate and depends on the specific appliance, its efficiency, and how you use it. An installer must replace these with your actual measurements.
| Load (approx., varies) | Typical daily energy (very approx., varies) | Notes |
|---|---|---|
| Central AC (3‑ton, summer) | ~20–40 kWh/day (or more) | Single biggest load; runtime depends on outdoor temp, insulation, thermostat setting. Startup surge can be 2–4× the running draw. |
| Refrigerator/freezer | ~1–3 kWh/day | Cycles on/off; newer models use less. Defrost cycles add spikes. |
| Lights, Wi‑Fi, router, small electronics | ~0.5–2 kWh/day | Modest combined draw. LED bulbs make a big difference. |
| Window AC or mini‑split (single room) | ~5–12 kWh/day | Significantly lower than central AC; still a large load if used for many hours. |
| Well pump (if present) | Highly variable | Intermittent; large startup surge that the inverter must handle. |
Key takeaway: Refrigerators, lights, and Wi‑Fi keep you functional at relatively low energy cost. Central AC is by far the biggest battery drain — plan accordingly.
Essentials, partial‑home, or whole‑home? (Tied to real costs)
How you use the battery shapes the price. At Voltkeep, we see three common target ranges (before any incentives, and prices change — get a current quote):
- Essentials backup ($8k–13k installed, approx.): Covers refrigerator, a few lights, Wi‑Fi, and maybe a gas furnace blower. Usually achievable with one battery unit. Minimal AC — maybe a small window unit or fan.
- Partial‑home backup ($12k–18k, approx.): Adds more circuits, such as a dedicated room AC, sump pump, or freezer, and may stretch to a few hours of central AC if the system is sized carefully. Often requires 1–2 battery units, plus a critical‑loads subpanel.
- Whole‑home backup ($18k–30k+, approx.): Aims to run everything, including central air conditioning for extended periods. Almost always needs 2–4 battery units and may require a smart load management system to avoid overloading the inverter. This is where costs climb fast.
These ranges reflect full installation in DFW and will vary with your home’s electrical setup. They do not include solar panels, which modify the equation.
The AC caveat: North Texas’s biggest battery challenge
Central air conditioning is a large, spiky load. A typical DFW home’s AC unit may draw several kilowatts when running and demand a brief, much higher startup surge (locked‑rotor amps) that can trip an undersized inverter. A battery system must:
- Have enough inverter output (kW) to start the compressor and run it alongside other loads.
- Store enough stored energy (kWh) to keep the compressor cycling through a sweltering afternoon and evening.
Without load management (like a soft starter or staggering multiple AC units), a single battery often can’t start a large central AC at all. Even when it can, the runtime may be measured in hours, not days. Fans, mini‑splits, or a small window unit consume far less energy and are much easier to back up.
How solar changes the math
If you pair batteries with solar, you can recharge during the day, effectively extending your runtime. In a long outage, a solar + battery system can cycle: solar charges the battery, battery runs the house at night. This reduces the brute‑force storage you’d otherwise need — but you still need enough battery to cover nighttime loads and any gap between solar production and peak usage. A cloudy spell can leave you short, so don’t assume solar makes a tiny battery sufficient.
Get it sized properly (professional load calc required)
The method above gives you a framework, not a final design. Only a licensed electrician or installer can perform a true load calculation, measure your appliances’ real draw, and confirm compatibility with your home’s wiring and the battery’s inverter. We built a free calculator to help you explore scenarios, but it’s a starting point, not engineering advice.
Estimates only. A licensed installer must perform the actual load calculation and system design. Try our free sizing tool, then get matched with a vetted DFW professional who can do the real work.
When comparing equipment for that design, review Tesla Powerwall vs Enphase vs Franklin.
Answer-first
Home battery sizing questions
How many Powerwalls do I need for a 2,000 sq ft house?
There is no square-footage rule. In a typical 2,000-sq-ft DFW home, a single battery unit (≈10–16 kWh usable) might cover essentials — lights, fridge, Wi-Fi — for about a day, but it won’t run central AC for long. For partial backup including a few hours of AC, you may need at least two units; whole-home coverage often needs three or more. An installer must match capacity and inverter output to your specific load list.
Can one battery run my whole home?
Rarely, unless your “whole home” is small, well-insulated, and you avoid large electric loads like central AC, electric water heaters, or pool pumps. Most DFW homes require multiple batteries to back up all circuits simultaneously. Expect to use a critical-loads panel to isolate what the battery supports.
How much battery do I need to run AC during an outage?
Air conditioning can consume roughly 3–5 kWh per hour of runtime (very approximate, varies by unit). A single battery might give you anywhere from 2 to 5 hours of continuous AC, assuming no other major loads, but the startup surge may prevent the battery from starting the compressor at all without a soft starter. For overnight or multi-day AC backup, you’ll likely need multiple battery units and possibly load management. Get a professional load analysis.
Does solar reduce how much battery I need?
It can, because solar recharges the battery during daylight, effectively lowering the raw storage required for a given outage length. However, you still need enough battery to get through nighttime and cloudy periods, and to handle peak AC loads when the sun isn’t shining directly on the panels. Solar plus battery is a system — size them together.
How do I know my exact size?
You don’t, without a measurement-based load calculation. Start by listing your must-have circuits, then talk to a licensed installer who will instrument your panel, check surge currents, and suggest a battery configuration that meets your goals. Online tools and tables can educate you, but they can’t replace on-site engineering.
All capacities, runtimes, and cost figures are estimates for educational purposes only. A licensed installer must perform the actual load calculation and design. Use our free calculator to explore scenarios, then connect with a qualified DFW professional.