After a nor'easter knocks out power for three days or a summer thunderstorm takes down the grid for 12 hours, the appeal of backup power is immediate. But when you start researching solutions, you quickly hit a fork in the road: a whole-home standby generator or a home battery storage system? They both keep your lights on during outages, but they work differently, cost differently, and make sense for different households.
Here is an honest comparison from electricians who install both in New Jersey every week.
How Each Technology Works
A standby generator (like a Generac, Kohler, or Briggs & Stratton) is a permanently installed natural gas or propane-fueled generator connected to your home via an automatic transfer switch (ATS). When the grid goes down, the generator detects the outage, starts automatically, and powers your home within 10–30 seconds. It can run indefinitely as long as it has fuel — and because it is connected to your gas line, it never runs out (unless gas service is also interrupted, which is rare).
A home battery (like a Tesla Powerwall 3, Enphase IQ Battery, or Franklin WH) stores electricity — from the grid or from solar — and discharges it when the grid is down. It switches to backup mode faster than a generator (typically in milliseconds). But it has a finite capacity: when the stored electricity is used up, the backup power ends unless solar is recharging the battery or the grid is restored.
Coverage: What Each System Can Power
A properly sized whole-home generator can power everything in your house simultaneously — central AC, electric range, water heater, EV charger, sump pump, security system, all lights and outlets. A Generac 22kW (our most commonly installed size for NJ homes) can handle a 3,500 square foot home with all modern appliances running at the same time.
A home battery can power essential loads — lights, refrigerator, phone charging, internet router, medical equipment, even a window AC unit — but has limited ability to run multiple high-draw appliances simultaneously. A single Tesla Powerwall 3 (11.5 kW continuous output) can handle most of a typical NJ home's non-HVAC loads comfortably, but running a central air system plus an EV charger plus a washer simultaneously will exceed its output. Two Powerwall units can cover most whole-home loads.
Outage Duration: The Critical Difference
This is where the generator wins clearly for long outages. After Superstorm Sandy, many NJ communities were without power for 7–14 days. A home battery cannot sustain a home for 14 days — even a large battery bank will be depleted in 1–2 days without solar recharging. A natural gas generator runs until the gas runs out (which, in most NJ scenarios, means it runs indefinitely).
For short outages — 4–24 hours, which represent the vast majority of NJ power outages — a well-sized home battery handles the situation just as well as a generator, and does it silently and without emissions.
Cost Comparison for NJ Homeowners
Whole-home standby generator (Generac 22kW, installed in NJ, including ATS and gas line work): $12,000–$18,000. No federal tax credit currently available. Annual maintenance cost: $150–$300 per year for service visits.
Home battery (Tesla Powerwall 3, installed in NJ): $12,500–$15,000 gross, reduced to approximately $7,000–$9,000 after federal 30% tax credit and NJ Garden State Energy Storage Program incentive. No fuel cost. Minimal maintenance.
On a net-cost basis after incentives, a home battery can be more affordable than a generator. The generator offers indefinitely longer runtime for the dollar when it comes to extended outages.
The Grid Benefits Argument: Batteries Win
A standby generator does exactly one thing: provide backup power during outages. A home battery does that plus:
- Time-of-Use rate optimization: Under PSE&G's TOU pricing (launching June 1, 2026), a battery that charges at $0.09/kWh off-peak and discharges at $0.31/kWh peak saves real money every day — whether the grid is up or down.
- Solar self-consumption: If you have solar, a battery stores excess daytime production for evening use instead of exporting it to the grid at low net-metering rates.
- Grid services: Some battery programs allow utilities to use your battery's capacity during grid emergencies in exchange for bill credits.
A generator only earns its value during outages. A battery earns value every single day.
The Right Answer for Many NJ Homes: Both
For homeowners who want maximum resilience — especially those in flood-prone areas or homes with medical equipment that cannot tolerate outages — the combination of a home battery plus a standby generator is the gold standard. The battery handles everyday TOU optimization and short outages seamlessly, while the generator kicks in as a backup for extended outages when the battery is depleted.
Not everyone needs both. For a household with no specific long-outage risk and an interest in daily energy savings, a battery alone is often the better investment. For a family that experienced Sandy and never wants to be without power for two weeks again, the generator's indefinite runtime is irreplaceable.
Not sure which is right for your home? We install both — Generac and Kohler generators and Tesla Powerwall, Enphase, and Franklin battery systems. Call (848) 294-1739 or visit malfettonegroup.com/contact for a free consultation.