Whole-Home Backup or Partial Backup: Choosing Your Powerwall Setup

The core difference in plain terms

A Powerwall does not decide on its own which appliances to run. The wiring does. How your home is connected to the battery determines which circuits stay live when the grid goes down.

Both setups behave the same when the grid is up. The difference only shows during an outage, and in how much installation work is needed.

• Whole-home backup: The battery system and its Tesla gateway sit between the utility and your main panel. When the grid fails, the whole panel is powered from the battery (and solar, if you have it).
• Partial backup: Selected circuits are moved to a separate backup loads subpanel. Only those circuits stay on during an outage. Everything else in the main panel goes dark.

How whole-home backup works

In a whole-home setup, the gateway is typically installed at or near the point where utility power enters the house. When it detects an outage, it disconnects your home from the grid and lets the battery carry the house. You usually do not have to decide which circuits matter ahead of time.

Whole-home does not mean unlimited. It means every circuit is available, and your usage habits and battery count determine how long the stored energy lasts.

• Lights, outlets, kitchen, and bedrooms all keep working, so an outage feels much less disruptive.
• No need to sort circuits into essential and non-essential groups.
• Often simpler for households that work from home, have medical-adjacent equipment needs, or want minimal lifestyle change during outages.
• Heavy loads such as central air conditioning, electric ranges, electric dryers, well pumps, and EV charging can drain a battery quickly if they run unchecked.
• Your system must be sized so that the battery's output can start and run the loads that actually kick on. One Powerwall may not carry everything at the same time.
• Depending on panel layout and service, the gateway placement can require more electrical work.

How partial backup works

In a partial setup, an electrician identifies the circuits you want protected and relocates them to a backup loads subpanel fed through the battery system. The rest of the home stays on the main panel and loses power in an outage.

• Refrigerator and freezer
• Lighting in main living areas
• Internet modem, router, and phone charging outlets
• Garage door opener
• Furnace blower or boiler controls
• Sump pump
• A few outlets for a home office
• Stored energy lasts longer because large discretionary loads are excluded.
• A single battery is often a more realistic fit for essentials.
• Can be a good match when the main panel is crowded or when you want to keep the system focused.
• Circuits not moved to the subpanel will not work in an outage, which can surprise family members.
• Moving circuits takes planning. Changing your mind later means more electrical work.
• Some homes end up with a mix of circuits that are awkward to separate.

Questions that decide the right setup

Work through these before you settle on a design.

Central AC, heat pumps, electric water heaters, electric ranges, pool pumps, and EV chargers are the usual culprits. If you want them running in an outage, you will likely need more battery capacity and a design that can handle their startup demand. If you are fine without them, partial backup is often enough.

Short outages of a few hours are easy for whole-home to cover if you are mindful. Multi-day outages favor a leaner partial setup, extra batteries, or solar that recharges the battery during the day.

Solar paired with a Powerwall can recharge the battery during an outage, which makes broader backup more practical. Without solar, the battery is a fixed supply until the grid returns.

More units add both stored energy and the ability to run more at once. Many homeowners start with whole-home wiring and add capacity later, or choose partial wiring to make one unit go further.

Panel capacity, available space, service size, and the distance between the panel and the battery location all shape the design. This is why a site visit matters more than any online rule of thumb.

Cost depends on the number of batteries, panel condition, wiring distance, permitting, and whether a subpanel is needed. Partial backup is not automatically cheaper, since a subpanel and circuit relocation add labor. We do not quote numbers without seeing your home.

A middle path: whole-home wiring with smart load management

You do not always have to choose a pure extreme. Some homeowners connect the whole panel for convenience, then manage consumption through the Tesla app, backup reserve settings, and habits during an outage, such as avoiding the dryer or oven. Others choose partial backup now and plan their wiring so expansion is easier later.

An experienced installer can talk through these options based on how your household actually lives, rather than a one-size-fits-all package.

Common mistakes to avoid

• Assuming whole-home means unlimited runtime. Capacity and output still apply.
• Underestimating startup demand of AC units and pumps.
• Picking circuits from memory. A walk through the panel with an electrician catches forgotten circuits like the sump pump or garage opener.
• Ignoring permits and utility interconnection. Installations typically involve local permitting and utility requirements, which a licensed installer manages.
• Treating this as a DIY project. Work inside a main panel and service connection is for licensed electricians.

What the installation process looks like

The path is usually: a home assessment, a recommended design (whole-home or partial, number of batteries, location), permitting and utility paperwork, installation and commissioning, and a walkthrough of how backup behaves in your app. For the full step-by-step process, see our Powerwall installation manual at chargehomesolutions.com/tesla-powerwall-installation-manual/.

Charge Home Solutions works through a Tesla-certified network of licensed and insured electricians across the country, so you can be matched with a qualified installer quickly and get a design recommendation based on your actual panel, not a guess.

Get a recommendation for your home

If you are torn between whole-home and partial backup, the fastest way to settle it is a look at your panel and your priorities. Book a free in-home estimate at chargehomesolutions.com/request-service or call 888-995-6044.