Vehicle-to-home (V2H) backup uses the big battery in an electric vehicle to run your house when the grid goes down. To do it safely you need three things that work together: an EV that supports bidirectional power, a charger or inverter approved to send power back out of the car, and equipment that disconnects your home from the utility before the car starts feeding it.
As of October 2026, the feature is real but not universal. GM says its V2H Bundle can deliver up to 9.6 kW to a properly equipped home, and Tesla lists up to 11.5 kW for Cybertruck Powershare. Most EVs on the road still cannot do it, and every working setup involves a licensed electrician, not a plug-in adapter.
Key takeaways
- V2H turns a parked EV into a whole-home or partial-home backup battery during an outage.
- It only works with a supported vehicle plus automaker-approved bidirectional equipment; ordinary chargers only send power one way.
- Your home must be isolated from the grid while the car powers it, which is the job of a transfer switch or built-in isolation device.
- V2L (outlets on the car) is simpler and cheaper but powers only what you plug in with extension cords.
- Expect professional installation, a permit in most places, and a reserve setting so you can still drive away.
What is vehicle-to-home backup?
Vehicle-to-home is one form of bidirectional charging: power flows into the car to charge it, and back out of the car when you need it. An EV battery stores direct current (DC), while your house runs on alternating current (AC), so an inverter has to convert the power somewhere along the way.
That inverter can live in one of two places. In some systems it sits inside the vehicle, and the car exports AC power to the home equipment. In others the car exports DC and the inverter is built into the wall-mounted charger. UL, the safety-testing organization, lists both designs under its category for EV charging equipment with bidirectional capability, evaluated against an outline called UL 9741.
Either way, during an outage the car behaves like a large home battery. The hub article on the home network and smart home is a good companion to this one, because many V2H setups are managed through the same apps and Wi-Fi network as the rest of your gear.
V2L vs V2H vs V2G: what is the difference?
Three acronyms get used interchangeably in marketing, but they describe very different setups. The key differences are what gets powered, what hardware is involved, and whether the car ever interacts with the utility grid.
| V2L (vehicle-to-load) | V2H (vehicle-to-home) | V2G (vehicle-to-grid) | |
|---|---|---|---|
| What it powers | Individual devices plugged into outlets on the car or an adapter | Your home wiring: selected circuits or the whole house | Your home and the wider utility grid |
| Hardware needed | Usually nothing beyond the car (sometimes an adapter) and extension cords | Bidirectional charger or inverter, isolation or transfer equipment, often a monitoring gateway | Bidirectional equipment approved by the utility, plus an interconnection agreement |
| Grid interaction | None | Home is disconnected from the grid while the car supplies it | Runs in parallel with the grid and can export power to it |
| Installation | None | Licensed electrician, permit in most areas | Electrician plus utility approval and program enrollment |
| Typical use | Camping, job sites, running a fridge or lamp by cord | Backup power during outages | Utility programs that pay or credit owners for grid support |
Comparison of bidirectional EV power modes. Capabilities vary by vehicle, equipment and utility; check your automaker and utility before buying hardware.
For a household, the practical choice is between V2L for occasional, cord-based backup and V2H for backup that runs through your normal outlets and lights.
How does V2H work when the power goes out?
The details differ by brand, but the sequence in automaker documentation follows a common pattern. Using GM and Tesla as examples, because both publish how their systems behave:
- Outage detected. The home equipment senses that grid power has stopped. GM says its V2H product disconnects the home from the grid and begins supplying power from the vehicle once an outage is detected, if automatic backup is turned on in the app.
- Brief blink. Tesla notes that the home may lose power briefly while the vehicle prepares to take over, so clocks and some electronics may reset.
- Car powers the house. The vehicle discharges through the bidirectional equipment. Output is capped by both the car and the charger, so large loads running at once can overload the system.
- Reserve limit. You set a minimum battery level in the app. Tesla calls it the Powershare discharge limit; when the battery reaches it, the car stops supplying the house so you keep enough range to drive.
- Grid returns. The equipment reconnects the home to the utility. Tesla warns the house may lose power for several seconds during this handover.
One practical detail from Tesla's manual: while Powershare is running, the truck's own cabin and bed outlets are disabled, and a cold high-voltage battery can interrupt backup, which is more likely in low temperatures or if the vehicle has not been driven recently.
Why is a transfer switch non-negotiable?
Any backup source that connects to your home wiring, whether a gas generator or an EV, has to be separated from the utility lines first. Otherwise power can flow backward out of your house, a hazard called backfeed. The Missouri Public Service Commission explains that a pole transformer can step backfeed up to thousands of volts, enough to kill a line worker repairing the outage some distance away. Its guidance is that the only safe way to connect a generator to existing wiring is a transfer switch installed by a licensed electrical contractor.
V2H equipment handles this with a transfer switch, a backup gateway or an isolation device built into the system. The National Electrical Code (NFPA 70), which most US jurisdictions adopt in some edition, covers EV charging equipment in Article 625; according to UL, inverters that export power from an EV to a house are intended to be installed under the code's interactive-system requirements in section 625.48. Local adoption and amendments vary, which is one reason the permit and inspection step matters.
The takeaway for homeowners is simple: never use a "suicide cord" or any adapter that feeds a house outlet from a car or generator. If a product promises whole-home backup without an electrician, treat that as a red flag.
What hardware do you need for vehicle-to-home backup?
- A V2H-capable vehicle. Support depends on the model, model year, software version and sometimes the trim. The owner's manual or the automaker's energy page is the authority, not a dealer's sales sheet.
- Automaker-approved bidirectional equipment. V2H systems are usually sold as matched sets: GM sells a V2H Bundle and a V2H Enablement Kit through GM Energy, and Tesla pairs Cybertruck with a Powershare Gateway or Powerwall depending on the home's configuration.
- Grid isolation. A transfer switch, gateway or isolation relay that disconnects the house from the utility during backup.
- A plan for loads. Many installs back up a subpanel of essential circuits rather than the whole house, which keeps big loads like an electric range or dryer from overwhelming the system.
- Monitoring. An app that shows battery level, estimated backup time and the reserve limit. GM says its tools can estimate backup time from the monitored parts of your home.
If you already have solar or a stationary battery, the EV setup has to be designed around it, because the inverters, gateway and transfer equipment need to agree on who is in charge during an outage.
- Confirm your vehicle supports V2H. Check the owner's manual and the automaker's energy or charging page for your exact model year, and note the required software version.
- Pick the equipment the automaker approves. Bidirectional charging needs the car and charger to speak the same protocol; mixing brands without official support can leave you with a one-way charger.
- Decide what you want backed up. List the essentials (refrigerator, lights, internet router, furnace fan, well pump, medical devices) and ask the installer whether a critical-loads panel makes more sense than whole-home backup.
- Hire a licensed electrician and pull a permit. The installer sizes the circuit, installs the isolation or transfer equipment and arranges inspection. Ask whether your utility needs to be notified.
- Set the reserve limit in the app. Choose a minimum battery level that leaves enough range to reach a shelter, a pharmacy or a fast charger if the outage drags on.
- Run a drill. With the installer or on a mild day, flip the main breaker or follow the manufacturer's test procedure, check which circuits stay on and note how quickly the battery drops.
- Keep a backup plan for the car. Decide what happens if the vehicle is away when the power fails, and keep a flashlight, a battery bank for phones and a paper list of important numbers.
How long can an EV run a house?
There is no single answer, because runtime depends on three numbers: how much battery energy is available above your reserve limit, how much power the house draws on average, and how efficiently the equipment converts DC to AC. The arithmetic is simple: usable kilowatt-hours divided by average kilowatts of load gives hours of backup, minus conversion losses.
As an illustration only, a car with 50 kWh available above its reserve supplying a home that averages 2 kW would last roughly 25 hours before losses. Cut the load to essentials averaging 1 kW and that roughly doubles. Air conditioning, electric heat and electric cooking push the average up quickly. Automaker figures are best-case estimates: GM, for example, says a 2026 Chevrolet Silverado EV Max Range can help power a properly equipped home for up to five days, a claim that assumes careful load management.
The power cap matters too: a system rated near 10 kW cannot run everything at once, and motors draw a surge when they start. Keep the router on an essential circuit, and remember that a power backup is not a data backup; the site's complete guide to backups covers protecting files separately.
Does vehicle-to-home damage the EV battery?
Powering a house adds charge cycles, and every lithium-ion battery slowly loses capacity with use, but occasional outage backup adds relatively few. Research is more nuanced than the common fear: NREL and Leiden University researchers found that well-managed grid participation could even help battery life, because batteries degrade faster when parked at a high state of charge and bidirectional use can lower that average.
The practical safeguard is the warranty. Read what your automaker says about bidirectional use, use only approved equipment, and keep the vehicle software up to date, since V2H behavior is often controlled by firmware.
When V2H is not the right move
- Your car is not supported. Many EVs cannot export power to a house at all, and a software update rarely adds the hardware capability.
- You rent or share a panel. V2H requires changes to the electrical service that landlords and condo boards must approve.
- The car is often away. If the vehicle is at work during the day, it cannot back up the house when an afternoon outage hits.
- You need guaranteed power for medical equipment. Talk to your doctor and utility about a dedicated backup with no dependence on the car being home and charged.
- Outages are rare and short where you live. A V2L setup with a few heavy-duty cords, or a small portable power station, may cover a two-hour outage for far less money.
- You may need to evacuate. In wildfire or hurricane zones, draining the car to keep the lights on can leave you with less range when you most need to leave.
For homes that want independence from the grid more broadly, V2H is one piece of a larger energy system that may include solar, a stationary battery or, in the right location, small wind; the older post on a mini wind turbine for home power shows how long people have been chasing that goal.
What to watch next
Policy is pushing in this direction. In September 2024 California enacted Senate Bill 59, which authorizes the California Energy Commission to require bidirectional capability in battery electric vehicles if it finds a compelling use case for owners and the grid. At the federal level, the Department of Energy launched a Vehicle-to-Everything (V2X) memorandum of understanding in April 2022 with national labs, utilities, states and private companies to study the technical and economic feasibility of bidirectional charging, with cybersecurity as a core focus.
For buyers, watch which new models ship with bidirectional support and whether your utility starts offering credits for grid support. Until then, stick with automaker-approved equipment and a licensed installer.
Frequently asked questions
Can any EV power my house?
No. The vehicle must be designed for bidirectional power export and paired with equipment the automaker supports. Check your owner's manual and the automaker's energy page for your exact model year; if V2H is not listed, assume it is not supported.
Does vehicle-to-home damage the EV battery?
Occasional outage backup adds some charge cycles but is not considered a major source of wear. NREL research suggests well-managed bidirectional use can even reduce time spent at a high state of charge. Check your warranty terms and use approved equipment.
Do I need an electrician for V2H?
Yes. Connecting any backup source to home wiring requires grid isolation, normally a transfer switch or gateway, installed by a licensed electrician, and most areas require a permit and inspection. Never backfeed a house through an outlet.
Is V2L enough for a power outage?
For short outages it can be. V2L runs devices plugged into outlets on the car, so it suits a refrigerator, lamps and phone chargers on extension cords, but it cannot power hard-wired loads like a furnace or well pump.
Will my EV keep enough charge to drive?
Most systems let you set a reserve or discharge limit in the app. When the battery reaches that level the car stops powering the house, so pick a limit that covers the trips you might need to make during a long outage.
Sources
- U.S. Department of Energy: Vehicle to Everything (V2X) Memorandum of Understanding announcement (accessed October 2026)
- NREL: Electric vehicles play a surprising role in supporting grid resiliency (accessed October 2026)
- NFPA 70, National Electrical Code (accessed October 2026)
- IAEI Magazine, UL Question Corner: bidirectional EV chargers that back-feed a house (UL 9741, NEC 625.48) (accessed October 2026)
- Missouri Public Service Commission: Generator safety tips (accessed October 2026)
- GM Energy: Vehicle-to-Home (V2H) (accessed October 2026)
- Tesla Cybertruck Owner's Manual: Powershare Home Backup (accessed October 2026)
- American Public Power Association: California Governor signs EV bidirectional charging bill into law (accessed October 2026)
Top image: "BMW i3 home charging L2 CRI 04 2021 9753" by Mariordo (Mario Roberto Durán Ortiz), CC BY-SA 4.0, via Wikimedia Commons (resized). Charts and tables by Thank You Robot.
0 Comments