RV OWNER’S FIELD GUIDE · APPLIANCES
12V vs. 120V Appliances Explained
Every RV runs both systems side by side. Knowing which is which changes what you can actually run off-grid.
12V DC — Runs Directly Off the Battery
Lighting, water pump, furnace fan/control board, most vent fans, and slide/leveling systems typically run on 12V DC directly from the house battery — no inverter required, and generally lower draw. This is why these keep working even with the inverter off.
120V AC — Needs Shore Power, Generator, or an Inverter
Microwave, residential-style fridge, AC unit, and standard household outlets are 120V AC — off-grid, that means running through an inverter, which draws from the battery bank far faster per watt-hour than an equivalent 12V load. This is the single biggest factor in how long a boondocking battery bank actually lasts.
Why It Matters When Buying or Upgrading
A 12V compressor fridge draws far less off-grid than a residential 120V fridge run through an inverter, even though the 120V fridge may have a larger interior. If off-grid capability matters more to you than looks, choosing 12V-native appliances where the option exists is worth more than extra solar wattage.