Whole-House or Partial Standby Generator for a Florida Home?

The decision starts with summer comfort, not square footage

After living through a prolonged outage, most homeowners are not asking for an abstract amount of backup power. They want the refrigerator cold, the lights and internet working, the garage door usable and, critically, the central air conditioner running during hot weather.

That requirement connects three decisions: which loads receive backup power, how much starting and running capacity those loads require, and whether natural gas or propane can supply the chosen generator. A partial-home system can meet the goal, but only when central air is deliberately included and its starting surge is addressed.

“Whole-house” also does not mean every electric appliance can run simultaneously without limits. The more useful distinction is between a selected-circuit system and a whole-service system that uses load management to decide when high-demand equipment can operate.

Key takeaways

For central air and refrigeration during a hurricane outage, a whole-service transfer switch with managed loads is often the more practical design. It preserves broader household access without requiring a generator large enough for every appliance to start at once.
Square footage does not determine generator size. Central AC starting current, a well pump, electric cooking, water heating, laundry equipment and EV charging can move two similar homes into different generator classes.
Partial backup works when the limits are intentional. It is a strong option for refrigeration, lighting, communications and selected outlets, or when one properly assessed AC system is included.
Natural gas is usually lower friction when adequate service already reaches the property. Propane is more practical when natural gas is unavailable, but tank placement, usable fuel capacity and storm-time refueling need to be planned.
Sizing and installed price are project-specific. The final specification requires equipment nameplates, electrical-panel conditions, fuel capacity, generator placement and the local permit path.

Generac’s sizing method accounts for both continuous demand and motor-starting requirements, while American Electrical Contracting begins with the circuits and systems the homeowner wants available during an outage. Generac generator sizing guidance explains why two equally sized homes can need different systems.

Whole-house and partial-home standby power compared

Decision point	Whole-house or whole-service design	Partial-home or selected-circuit design
Electrical architecture	An automatic transfer switch connects the generator to the home’s service, with load controls limiting selected high-demand equipment.	A transfer panel or configured switch supplies only designated circuits and appliances.
Central air conditioning	Usually easier to include, provided the AC starting current is measured and managed.	Must be explicitly included. A basic essentials package may omit central AC entirely.
Simultaneous loads	Provides broad access, but the range, dryer, water heater, EV charger or additional AC systems may be paused when demand rises.	Capacity is protected by limiting which circuits are connected from the outset.
Outage experience	Closer to normal household operation, especially when load priorities are configured correctly.	Requires more awareness of what is backed up and which appliances can be used together.
Generator capacity	Often larger, although load management can reduce the capacity required for whole-service coverage.	Often smaller because nonessential and high-demand circuits remain outside the backup system.
Installation tradeoff	A service-rated transfer switch can reduce circuit-by-circuit selection while adding load-management design.	Can reduce generator and fuel requirements, but selected circuits must be mapped accurately.
Stronger choice when	The homeowner wants central AC, household convenience and flexibility during a multi-day outage.	The goal is a defined essentials package, available installation space is limited, or the homeowner accepts firm operating boundaries.

Sources: American Electrical Contracting installation considerations and Generac automatic transfer switch specifications.

Worked example: a 2,000 square foot Northeast Florida home

Consider a hypothetical 2,000 square foot home with one 3-ton central AC system, a refrigerator, a well pump, a microwave, selected lighting and receptacles, home networking and a garage door opener. The figures below are planning assumptions, not a final load calculation. Actual equipment nameplates and measured starting current control the specification.

Backup load	Illustrative running demand	Starting or usage consideration
3-ton central AC	4.5 kW	Assume up to 16 kW total starting demand. The actual compressor LRA and any soft-start equipment must be checked.
Refrigerator and freezer	0.7 kW	Allow approximately 2.2 kW of additional starting demand.
One-third horsepower well pump	1.0 kW	Allow approximately 2.2 kW of additional starting demand. Remove this load for a city-water property.
Microwave or one countertop cooking load	1.0 kW	This does not represent an electric range or oven.
Selected lighting, receptacles and network	0.8 kW	An illustrative allowance that must be replaced with the project’s calculated load.
Garage door opener	0.75 kW	Intermittent use, preferably kept away from a major motor-starting event.

The running stack is approximately 8.75 kW. If the AC starts while the other loads are already running, the momentary requirement approaches 20.25 kW. If the well pump also attempts to start at that moment, the combined event can rise further.

This is where load management changes the purchase. A control system can delay the well pump, cooking load or another lower-priority appliance while the AC compressor starts. A verified soft-start solution can also reduce the AC starting burden. The homeowner may then receive broad household coverage from a smaller unit than an unmanaged calculation suggests.

Generac’s August 2026 planning guidance places many 2,000 square foot homes in an 18 to 22 kW range, while allowing smaller systems where starting current is reduced and large loads are actively managed. Electric ranges, electric water heaters, clothes dryers, pool equipment and EV chargers must be added to the analysis or assigned a lower priority. Generac’s home standby buyer guide provides the refrigerator and well-pump reference values.

What the example actually tells the homeowner

An essentials-only system without central AC does not satisfy a central-AC backup requirement.
An unmanaged system must absorb the worst credible motor-starting event. That can push the specification toward a larger generator.
A managed whole-service system can energize more of the house without promising unlimited simultaneous use.
A home without a well pump has materially more available capacity.
A second AC system, large heat pump or electric water heater can change the recommendation.

What disappoints homeowners about partial backup

The first failure is often a mismatch between the homeowner’s idea of “essentials” and the circuits included in the project. Refrigeration and lighting may work exactly as designed, but the house still becomes difficult to occupy because central AC was left outside the backup panel.

The next problem is starting surge. An AC system can draw several times its running demand while the compressor starts. A generator that appears adequate after adding steady-state wattages can overload when the AC, refrigerator or well pump cycles at the wrong moment.

Partial backup remains the stronger choice when those limits match the homeowner’s real priorities. It becomes a false economy when central AC is added informally, without checking compressor data, fuel rating and the other motors likely to start during the same period.

Natural gas or propane in Northeast Florida?

Fuel question	Natural gas	Propane
Availability	Requires active service at the address plus adequate meter, pressure and line capacity.	Can serve properties without utility gas, subject to tank access, placement and permitting.
Multi-day outage logistics	No onsite refilling is required while utility gas remains available.	Fuel is stored onsite, but runtime is finite and replenishment depends on delivery access after the storm.
Generator output	Some dual-fuel models produce less rated power on natural gas. The chosen model’s NG rating must be used for sizing.	Some models retain their higher nameplate output on propane.
Site work	May require a larger meter, regulator or new gas piping sized for the generator and existing appliances.	Requires a suitably sized tank, code-compliant setbacks, a fill route and protection from vehicles or flooding.
Stronger choice when	The property already has adequate gas service and the homeowner wants the least refueling responsibility.	Natural gas is unavailable or inadequate, and the property has space for a tank and a realistic refill plan.

A current Generac 28 kW model, for example, is rated at 28 kW on propane and 25 kW on natural gas. That difference cannot be applied to every model, but it demonstrates why sizing must use the selected fuel rating rather than the largest number in the product name. Generac also requires an appropriately sized gas meter or propane tank and identifies 250 gallons as the minimum propane tank size for its home standby line. Generac 28 kW specifications and Generac installation guidance provide the model and fuel-system details.

Natural gas avoids scheduling a propane delivery during a regional outage, but it is not an independent fuel reserve. Utility gas can be interrupted or intentionally shut down after some disasters. Propane provides onsite inventory, but the tank must contain enough usable fuel for the planned load and operating duration. FEMA utility-loss guidance addresses both utility-gas interruption and onsite fuel planning.

What installation actually involves

Load assessment and equipment selection. The electrician documents the desired circuits, AC starting data, well equipment, major electric appliances, service size and panel arrangement.
Generator and transfer-switch design. The project specifies the generator’s fuel-specific output, automatic transfer switch, service rating and any load managers or AC soft-start equipment.
Placement and site preparation. The location must satisfy equipment clearances, exhaust safety, service access, property constraints and flood requirements. The generator is installed on an approved stable base, commonly a prepared concrete pad or manufacturer-approved pad.
Electrical installation. Conduit and conductors connect the generator, transfer switch and service equipment. The transfer switch isolates the home from utility power before generator power is applied.
Fuel coordination. Natural-gas work can involve meter and pipe-capacity review. Propane work includes tank sizing, siting, regulators and piping. Fuel pressure and leak testing are completed before startup.
Permits, inspection and commissioning. After required electrical, gas and generator approvals, the installer simulates an outage, confirms transfer operation, activates the equipment and explains routine operation to the homeowner.

Generac installations commonly include site preparation, a concrete slab or approved alternative, an automatic transfer switch, electrical wiring and a fuel connection. Generac installation guidance also calls for a simulated outage before handoff.

Permit details differ across American Electrical Contracting’s service area. Jacksonville routes permit submissions through JaxEPICS. St. Johns County requires generator size, transfer-switch information, calculated load and fuel details, with a separate gas or piping permit for a new fuel source. Clay County lists a residential generator permit, and Nassau County maintains a dedicated standby generator application and inspection process. Jacksonville Building Inspection Division, St. Johns County generator worksheet, Clay County residential permit list and Nassau County permit forms document the local processes.

What manufacturer-certified installation changes

American Electrical Contracting is manufacturer-certified for Generac generators and Reliance Controls transfer switches. Certification connects the installation to product-specific training, setup procedures and an established service path after the system is commissioned.

For Generac systems, warranty repairs and related concerns must be handled by an authorized or certified Generac service dealer, and damage caused by improper installation is excluded. Reliance Controls also excludes improperly installed transfer switches from warranty coverage. Certified installation does not replace county permitting or final inspection, and it does not make every future repair a warranty repair.

The practical advantage is continuity. The contractor assessing the loads can specify the transfer equipment, coordinate fuel work, activate the generator and remain available for maintenance and service. American Electrical Contracting provides Generac sales, installation, repairs, load testing and ongoing service in Duval, St. Johns, Clay and Nassau counties. American Electrical Contracting’s Generac services, Generac’s limited warranty and Reliance Controls warranty terms provide the relevant service and warranty details.

When to choose each backup approach

Choose whole-house or whole-service backup when

Central AC is a non-negotiable requirement during a summer outage.
You want broad access to household circuits without building a narrowly selected emergency panel.
You accept that load management may temporarily pause an EV charger, dryer, water heater or other lower-priority equipment.
The house has several motor loads whose starting sequence needs to be controlled.

Choose partial-home backup when

Your defined goal is refrigeration, communications, lighting and a small number of receptacles.
You can comfortably live without electric cooking, laundry, water heating or other large loads during an outage.
Central AC is either outside the project or has been specifically assessed and included.
A smaller fuel requirement and tightly controlled scope matter more than normal household convenience.

American Electrical Contracting is the best fit when

The home is in Duval, St. Johns, Clay or Nassau County.
You want the electrical assessment, transfer-switch design, generator installation and long-term service coordinated through one contractor.
You want a clear explanation of what the generator will support before selecting equipment.
The project may uncover related panel, service-capacity or wiring work that should be evaluated with the generator installation.

American Electrical Contracting is not a fit when

The property is outside Duval, St. Johns, Clay or Nassau County.
You want equipment selected from square footage alone without a site-specific electrical and fuel assessment.

Frequently asked questions

What size standby generator does a 2,000 square foot house need?

An 18 to 22 kW generator is a useful planning range for many 2,000 square foot homes, but it is not a prescription. A home with central AC, a well pump and electric cooking can require more capacity or active load management. A home with city water, gas appliances and a verified AC soft start may require less. The final size must use the AC compressor’s starting data, the chosen fuel rating and the household’s actual backup priorities.

Can a partial-home generator run central AC and a refrigerator?

Yes, a partial-home system can run central AC and refrigeration when both are included in the design and the generator can handle the AC starting event. The refrigerator is rarely the deciding load. Central AC compressor surge, a well pump and other motors usually control the specification. Load management can prevent lower-priority equipment from starting while the air conditioner is placing its highest demand on the generator.

Should I choose natural gas or propane for a Northeast Florida generator?

Natural gas is usually the lower-friction choice when adequate utility service already reaches the home. It avoids onsite refilling, although the meter and piping still need capacity for the generator. Propane is often more practical where natural gas is unavailable, but the project needs a compliant tank location and enough usable fuel for the expected outage. The generator must be sized using its rating on the selected fuel.

How much does a whole-house generator cost installed?

Installed cost is project-specific because the generator is only one part of the system. The transfer switch, load managers, concrete or approved base, conduit distance, panel modifications, gas meter or propane tank, fuel piping, permits and site restoration all affect the quote. A credible price follows a property assessment and load specification rather than square footage alone.

Does whole-house backup let me run every appliance at once?

No, whole-house backup often means the whole electrical service is connected, not that every high-demand appliance can operate simultaneously. Load management temporarily pauses lower-priority equipment when generator demand approaches its limit. This arrangement can keep central AC, refrigeration, lighting and normal receptacles available while delaying an electric dryer, water heater, range or EV charger.

Why use American Electrical Contracting for a standby generator?

American Electrical Contracting can assess the home’s loads, install the generator and transfer equipment, coordinate the fuel connection and provide ongoing Generac service. Its Generac and Reliance Controls certifications are particularly relevant when the homeowner wants one local contractor responsible for installation and the later service path. Service is limited to Duval, St. Johns, Clay and Nassau counties.