Home Backup Power:
A Homeowner’s Guide

Home backup power is not one piece of equipment. It is a system built around what you want to keep running during an outage, how much power those loads need, how long you need them to run, and how the backup source connects to your home safely. For most homeowners, the main choices are a standby generator, a portable generator, a home battery, or a combination of systems.

The useful starting point is not “What size generator or battery should I buy?” It is “What do I need to keep powered, for how long, and how automatic do I want the system to be?” Those answers determine whether you need whole-home or essential-load backup, whether fuel or stored energy makes more sense, what transfer and control equipment is required, and whether your electrical system needs additional work.

For a step-by-step explanation of the outage sequence and how the equipment works together, see how home backup power systems work.

Compare whole-home and essential-load backup to decide which circuits and appliances you want available during an outage.

Start with the loads you actually want during an outage

A backup system should be planned around the home functions that matter to you, not around a generic “whole-house” label. One household may care most about refrigeration, a sump pump, internet, a few lights, and medical equipment. Another may want central air conditioning, a well pump, cooking equipment, and most normal household circuits available.

This creates the first major decision: do you want to back up a defined group of essential loads, or do you want a system designed to support most or all of the home?

• Essential-load backup: focuses available power or stored energy on selected circuits or appliances. It can reduce equipment size, fuel demand, battery capacity, and project scope.
• Whole-home backup: aims to preserve more of the home’s normal operation, but “whole home” does not always mean every large load can run at the same time. Load management may still be part of the design.

Large motors and compressors also matter because their starting demand can be higher than their steady running demand. That is one reason a simple list of appliance wattages can be useful for early planning but should not be treated as a final sizing method.

The main types of home backup power

Standby generators

A standby generator is permanently installed outside the home and is typically paired with automatic transfer equipment. When utility power is lost, the system can detect the outage, start the generator, transfer selected loads to generator power, and later return the home to utility power when service is restored.

A standby generator may fit well when you want automatic operation, expect outages that may last many hours or days, and have a practical fuel source such as natural gas or propane. Its limitations include fuel dependence, engine maintenance, noise, site-placement constraints, and a more involved installation.

Next: read the whole-house generator guide and generator sizing guide.

Portable generators

A portable generator can provide lower-cost backup for selected loads, but it requires more homeowner involvement. Depending on the setup, loads may be powered directly with properly rated cords or through professionally installed transfer equipment and an inlet that allows selected home circuits to be supplied safely.

Portable generators are fuel-burning equipment and require a separate safety plan for placement, exhaust, fueling, weather exposure, and connection. They are not a substitute for transfer equipment when feeding a home’s wiring.

Home battery backup

A home battery stores electrical energy and supplies it later through power electronics when the home needs it. During an outage, a properly designed battery system can separate the backed-up portion of the home from the grid and supply selected loads without a running engine.

A battery may fit well when quiet operation, automatic transfer, low routine maintenance, and short-to-moderate outage support are priorities. The important limitation is that battery duration depends on stored energy and the loads using it. High power output does not automatically mean long runtime.

Batteries can be installed with or without solar, depending on the equipment and local requirements. Solar can extend resilience in some system designs, but this guide treats solar only as one possible charging source rather than as a requirement for battery backup.

Next: read the home battery backup guide or compare generator vs. battery backup.

Portable power stations and smaller backup devices

Portable power stations can be useful for a small group of plug-in loads such as electronics, a modem or router, lighting, or some small appliances. They can be a practical resilience layer, but they should not be confused with a permanently installed home battery or a system designed to supply large hardwired loads.

The power source is only one part of the system

A useful backup-power plan has several layers: the power source, the loads, the transfer or control equipment, the home’s electrical distribution system, and the fuel or stored energy that determines how long the system can operate.

• Power source: Generator, home battery, portable power station, or a coordinated combination.
• Loads: The circuits and equipment you want available during an outage.
• Transfer and control: Equipment that prevents the backed-up home circuits from being connected to the utility source at the same time and, depending on the design, selects or manages loads.
• Electrical distribution: The panel, subpanel or critical-load arrangement, service equipment, breakers, conductors, and available electrical capacity that the installation must work with.
• Fuel or stored energy: Generator fuel supply or battery energy capacity. This is what ultimately governs how long the system can continue supporting a given load.

Transfer equipment deserves special attention. A generator or battery connected to home wiring needs a controlled way to separate backup power from utility power. The exact equipment may be an automatic transfer switch, manual transfer switch, listed interlock arrangement, or battery-specific gateway/control equipment, depending on the system.

Next: learn how generator transfer equipment fits into the system.

kW and kWh answer different questions

Backup-power planning becomes much easier once you separate power from energy:

• kW (kilowatts) is power. It describes how much electrical demand a source can support at a given moment.
• kWh (kilowatt-hours) is energy over time. For batteries, it helps describe how much energy is stored and therefore contributes to runtime.

Generator planning is often dominated by power output, starting demands, and fuel availability. Battery planning must consider both power output and stored energy. A battery can have enough instantaneous power to start a load but still have limited runtime if that load consumes substantial energy over time.

How long should backup power last?

There is no single correct runtime target. Think in terms of the outage you are planning for and which loads must remain available through it.

• Short interruptions: A battery or portable power station may cover communications, refrigeration, lighting, or other selected loads without running an engine.
• Overnight or multi-hour outages: Battery capacity, load reduction, generator fuel availability, or a combined approach become more important.
• Long-duration outages: Fuel logistics, generator maintenance, battery recharge options, and the ability to reduce nonessential loads can matter as much as nameplate system size.

For batteries, runtime is not a fixed specification that applies to every home. It changes with the load, usable battery capacity, reserve settings, system losses, and operating conditions. For generators, runtime depends on fuel supply, load, maintenance limits, and the exact equipment.

Automatic backup vs. manual backup

Your electrical system may change the project

Backup power has to integrate with the electrical system that is already in the home. That does not mean an older panel or a particular amp rating automatically requires an upgrade. It means the installer needs to evaluate the actual configuration, available capacity, breaker space, condition of equipment, backed-up loads, transfer/control method, and any other new loads being added.

A home that is also adding an EV charger, heat pump, electric water heater, induction cooking, or other large electric loads may need a broader electrical-readiness review. In some projects, load management can reduce simultaneous demand and may change whether a larger service or panel project is necessary.

Next: review home electrical upgrades and, if relevant, home EV charging.

Do you need a generator, a battery, or both?

Some homes benefit from combining a battery with a generator. A battery can provide quiet, immediate backup for selected loads while a generator can support longer outages or recharge strategies, depending on the equipment. Compatibility and control logic are system-specific, so a combined design should be verified for the exact equipment rather than assumed from brand names or connector types.

Cost depends on the system around the equipment

The purchase price of a generator or battery is only part of a backup-power project. Installation cost can change substantially based on what has to happen around the equipment.

• Backup capacity and the loads the system is expected to support.
• Automatic vs. manual transfer and the type of control equipment.
• Panel, subpanel, service, breaker, or load-management work.
• Generator fuel work, tank or meter considerations, and site access.
• Battery quantity, power electronics, backup gateway/control equipment, and installation location.
• Trenching, conduit, concrete pads or mounting, wall penetrations, and restoration.
• Permits, inspections, utility coordination, and local labor.
• Maintenance plans, monitoring, accessories, and future expansion.

For a planning budget, compare complete installed scopes rather than equipment prices alone. Separate cost guides should be used for current, sourced dollar ranges.

Permits, codes, and placement vary by project

Backup-power installations can involve electrical, building, fire, fuel-gas, zoning, utility, and manufacturer requirements. The applicable rules depend on the equipment, the property, the utility, and the local authority having jurisdiction. That is why a national guide should not give one universal generator setback, battery location, transfer-switch requirement, or service-upgrade rule for every home.

A qualified installer should confirm the current equipment instructions and local requirements before finalizing placement or installation. For projects that change service equipment or add substantial electrical load, the utility may also have requirements or coordination steps.

Who should evaluate a home backup-power project?

The right professional depends on the system. A licensed electrician is central to work involving panels, transfer equipment, service capacity, hardwired batteries, and home EV charging. A standby-generator project may also involve a generator dealer or installer and a qualified fuel-gas or propane professional. Battery projects may involve a specialized energy-storage installer. Utility or permitting-authority involvement can also be part of the process.

A useful site evaluation should connect the equipment choice to the actual loads, home electrical system, transfer/control method, installation location, fuel or storage plan, permits, and maintenance expectations — not simply recommend a product size from square footage.

Next: use the home power project-planning hub.

A practical way to choose your next step

1. Define the outage goal. List what must keep running and what can remain off.
2. Decide whether you want automatic or manual backup. This quickly narrows the system categories.
3. Separate power from runtime. Estimate peak/running power needs, then consider how long the source must support them.
4. Compare fuel and stored-energy constraints. Think about fuel availability, battery capacity, recharge options, noise, maintenance, and long-outage planning.
5. Check home readiness. Have the electrical system, transfer/control plan, equipment location, and local requirements evaluated.
6. Compare complete installed scopes. Make sure quotes include enabling electrical work, transfer equipment, fuel work or battery controls, permits, commissioning, and restoration as applicable.

Related guides and tools

Explore the related guides and generator calculator below.

• Whole-House Generators: A Homeowner’s Guide
• What Size Generator Do I Need for My House?
• Generator vs. Battery Backup
• Home Battery Backup: A Homeowner’s Guide
• Generator Transfer Switches: A Homeowner’s Guide
• Home Electrical Upgrades: A Planning Guide
• Home EV Charging: A Homeowner’s Guide
• Home Power Project Planning
• Home Generator Size Calculator

The bottom line

The right backup-power system starts with the loads and outage experience you want, then works backward through power, runtime, transfer/control, fuel or stored energy, and home readiness. A standby generator may be the better fit for long automatic backup where fuel is practical; a battery may be attractive for quiet automatic backup and shorter-duration resilience; a portable generator can cover essential needs with more manual involvement; and some homes benefit from a coordinated combination.

Before buying equipment, make sure the plan accounts for the home’s actual loads, starting demands, electrical configuration, installation location, and local requirements. That is the point where a planning estimate should become a site-specific design reviewed by the appropriate qualified professional.

Sources

1. U.S. Consumer Product Safety Commission (CPSC) — Carbon Monoxide Information Center (opens in a new tab) — Current web guidance; accessed September 23, 2026.

2. Federal Emergency Management Agency (FEMA) — Use Generators Safely at Home (opens in a new tab) — Page print dated September 26, 2025; accessed September 23, 2026.

3. U.S. Department of Energy — Home Upgrades (opens in a new tab) — Current web guidance; accessed September 23, 2026.

4. U.S. Department of Energy — Solar and Resilience Basics (opens in a new tab) — Current web guidance; accessed September 23, 2026.

5. U.S. Department of Energy, Alternative Fuels Data Center — Charging Electric Vehicles at Home (opens in a new tab) — Current web guidance; accessed September 23, 2026.