Florida Generator Size and Cost Calculator

Power outages after Florida hurricanes can last days, sometimes longer in hard-hit areas. Check the items you want to run at the same time. The calculator adds approximate running wattages, adds a 25 percent buffer, and suggests a generator size with a rough price range. Wattages below are typical figures; check the labels on your own equipment for accuracy, and remember that motors (refrigerators, well pumps, AC) need extra surge power to start.

Running watts vs. starting watts

Every appliance with a motor or compressor draws a short burst of extra power when it starts, often two to three times its running wattage. A refrigerator that runs at 700 watts might need 1,500 to 2,000 watts for a second when the compressor kicks on. Central air conditioners have especially high starting loads unless they have a soft-start kit. Generators list both a running (rated) and a starting (surge) wattage. Make sure the generator's surge rating covers your largest motor starting while everything else is running. You can reduce the problem by starting big loads one at a time.

Portable vs. standby generators

Portable and inverter generators

Portable generators are the most common choice in Florida. Small inverter models are quiet, fuel-efficient and produce clean power for electronics, but usually cannot run central AC. Larger open-frame portables can run a fridge, fans, lights and possibly a window unit. Many newer models are dual-fuel and can run on gasoline or propane. Propane stores far better than gasoline, which goes stale in months and is hard to find after a storm.

Standby generators

Standby generators are permanently installed outside the house, run on natural gas or propane, and switch on automatically through a transfer switch when the power fails. They can be sized to run the whole house, including central AC. They cost much more, need a permit, an electrician, often a plumber or gas contractor, a concrete pad, and placement that meets the manufacturer's and code clearance rules. They also need annual maintenance. For people with medical equipment, older relatives, or homes that must stay cool, many find them worth it.

Connecting a portable generator safely

Never plug a generator into a wall outlet ("backfeeding"). It can send power back into the utility lines and kill line workers, and it can damage your home's wiring. The safe options are heavy-duty extension cords run directly to appliances, or a transfer switch or interlock kit installed by a licensed electrician with a proper inlet box. An interlock lets you power selected circuits through your main panel. Expect a permit and an electrician's fee for this work.

Carbon monoxide: the biggest danger

Generator exhaust contains carbon monoxide, which is invisible, odorless and deadly. Every hurricane season, Florida sees CO poisonings and deaths after storms. Run generators only outdoors, well away from doors, windows and vents. The CDC and the U.S. Consumer Product Safety Commission advise keeping them at least 20 feet from the house with the exhaust pointed away. Never run one in a garage, even with the door open, on a lanai, or under a carport against the house. Install battery-powered or battery-backup CO alarms inside. Many newer portable generators include CO shut-off sensors; that is a worthwhile feature.

Fuel planning

Estimate how much fuel you need. A mid-size portable generator might burn roughly half a gallon to a gallon of gasoline per hour at moderate load; check your model's runtime chart. Over a multi-day outage that adds up fast, and gas stations may be closed or have long lines. Store fuel in approved containers away from the house, use a fuel stabilizer, and rotate gasoline every few months. Propane tanks store for years, which is why dual-fuel generators are popular. For standby units on propane, size the tank for the outage length you want to cover; natural gas service, where available, avoids refueling altogether.

Generators and Florida HOAs and codes

Florida law limits the ability of HOAs to ban permanently installed generators on single-family homes, though associations may still regulate placement, screening and noise within limits. Condos have their own rules. Local codes regulate standby generator placement relative to windows, doors and property lines. Your installer should handle the permit and placement requirements.

Testing and maintenance

Start portable generators every month or two and run them under load for a few minutes. Change the oil on schedule, keep spare oil and spark plugs, and drain or stabilize fuel. Standby generators usually run a short self-test weekly and need an annual service. Check before June 1 that everything works, cords are in good condition and you have enough fuel.

Battery alternatives

Portable power stations and home battery systems, sometimes paired with solar, can run small loads silently and with no exhaust, which makes them safe indoors. They are excellent for phones, CPAP machines, lights, fans and routers. Running a refrigerator for days or central AC requires a large battery bank or solar recharging. Costs range widely, from a few hundred dollars for small units to five figures for whole-home systems.

Medical equipment and special needs

If anyone in your home relies on oxygen concentrators, CPAP machines, refrigerated medication or powered mobility devices, plan power for them first. Check each device's wattage on its label or manual, and consider a battery backup so the device keeps running while you start the generator. Many Florida counties run a special needs shelter registry for residents who depend on electricity for medical reasons; registering ahead of hurricane season is free and gives emergency managers a way to plan for you. Florida Power & Light, Duke Energy and other utilities also suggest that medically dependent customers have a backup plan, because no utility can guarantee priority restoration after a major storm.

Frequently asked questions

What size generator do I need to run a refrigerator, lights and fans?

For most homes, a generator in roughly the 3,000 to 5,000 watt range covers a refrigerator, lights, fans, a router and phone charging, with surge capacity to restart the fridge. Add a window AC and you are often looking at 5,000 to 7,500 watts.

Can a portable generator run central air?

Some large portables can run a smaller central AC system, especially with a soft-start kit installed on the AC, but many cannot. A licensed HVAC tech or electrician can measure your unit's starting current.

Do I need a permit?

Plugging appliances into a portable generator with cords does not usually need a permit. Installing an inlet, transfer switch, interlock, or standby generator does.

Getting ready for hurricane season? Price hurricane shutters and review the RV hurricane checklist if you own an RV.