Sizing solar for backup means matching your daily watt-hours to peak sun hours where you live — not whole-home offset. I start with essentials: fridge, lights, phones, and medical gear. That's what keeps a family functional when the grid drops.
Written by Mike, a union electrical lineman with 21+ years on the job and mutual aid deployments after Sandy, California wildfires, Texas winter storms, and Gulf Coast hurricanes.
The average U.S. home uses about 29 kWh per day. — U.S. Energy Information Administration (EIA), 2023
For a 1,000Wh battery bank, plan on 200–400W of solar to recharge in 4–6 hours of peak sun. A single 200W panel in a good sun location (5+ peak hours) can deliver around 1,000Wh per day. Add more panels if you're in a low-sun region or need faster recharge.
Most RV setups need 400–800W of solar to run basic loads: lighting, phone charging, a fan, and a 12V fridge. If you're running a full-size compressor fridge and AC, budget 1,200W or more. Start by calculating your daily watt-hour usage, then size panels to cover it in your region's average peak sun hours.
Yes — a 12V compressor fridge uses roughly 30–60Wh per hour and runs 24/7 (about 400–800Wh per day). A 200W panel in a good location produces about 800–1,000Wh daily, which can cover a single fridge when paired with a power station as overnight buffer.
The average U.S. home uses about 29 kWh per day (EIA, 2023). At 4–5 peak sun hours, you'd need roughly 20–25 standard 400W panels for full household usage. For emergency backup covering essentials only — fridge, lights, phone, medical devices — 2–4 panels with a large power station is realistic.