Outage planning guide
What size power station will run a freezer overnight?
A freezer’s average load depends on size, insulation, ambient temperature and how often it is opened. Enter measured average watts for the most useful result.
Backup power runtime
Estimate steady-load runtime after inverter losses and a safety reserve.
Runtime = capacity × efficiency × usable battery share ÷ average load. Motor surge, temperature, battery age and device cycling can change real-world runtime.
What changes the answer?
Use energy over time, not only running watts
A plug-in meter can show watt-hours used over 24 hours. Divide by 24 to estimate average watts for the calculator while still checking the separate startup surge.
A full, closed freezer holds temperature longer
Thermal mass and limited door openings can reduce compressor runtime and preserve temperature, but electrical runtime alone does not determine food safety.
Plan for recharge, not just one discharge
For multi-day outages, include a realistic solar, vehicle or generator recharge plan and the charging time supported by the power station.
Use this result as a planning range
Use official guidance to decide whether frozen food is safe after an outage; this tool only estimates battery runtime.
Review the formulas and public sources in our methodology.
Official references
- Analyzing household electricity loadsU.S. Department of Energy
- Food safety during a power outageFoodSafety.gov
- Generator and carbon-monoxide safetyU.S. Consumer Product Safety Commission