Quick answer: A typical family needs 5–10 kWh to cover essentials (fridge, lights, medical equipment, phone charging) for a 3-day hurricane or ice-storm outage.
Emergency Power Planner
Size your backup power for emergencies — hurricanes, ice storms, and extended outages. Prioritized by what matters most.
How we calculate emergency power needs
The planner totals the watt-hours for each prioritized load across your target outage duration, then adds a safety buffer and recommends a backup solution tier.
Loads are ranked by priority tier — life safety first, then food preservation, then communications — so the most critical needs are always covered.
Frequently Asked Questions
- How much power do I need for a 3-day emergency?
- For a typical family of 3–4, plan on 5–10 kWh for a 3-day outage covering fridge, lights, phone charging, and a CPAP machine.
- What backup power do I need for medical equipment?
- Medical devices like CPAP, oxygen concentrators, and home dialysis require reliable power. A permanent home battery with automatic transfer switch is strongly recommended over a portable solution.
- How do I prepare for a hurricane power outage?
- Start with essentials: refrigerator, medical devices, lighting, and communication. A 5–10 kWh portable power station handles most needs for 2–3 days. For longer outages, a generator or home battery is needed.
Reviewed April 2026
Methodology and source note
PowerSizing calculators use shared formulas, documented assumptions, and current planning inputs that are summarized on the methodology page. Use these tools for first-pass planning, comparison, and sanity checks, then confirm local code, pricing, utility tariff, and installer specifics before you buy equipment.