Size portable home backup by calculating essential daily energy in watt-hours and checking output compatibility separately. Start with your own loads and outage duration; an arbitrary 1000Wh label or a “whole-home” claim cannot answer those questions.
Editorial correction: Earlier versions included unsupported testing, experience or performance claims. This research guide replaces those claims. Examples below are calculations, not measurements made by Wild Smart Gear.
Make one row per actual load
| Load | Planning input |
|---|---|
| Router, modem and ONT | Measure the complete powered network arrangement |
| Household refrigerator/freezer | Use representative daily Wh and verify compressor startup |
| Lighting and charging | Watts × intended hours, with supported supplies |
| Medical equipment | Manufacturer-supported backup and clinical continuity plan |
| Heating/cooking equipment | Check output limits and the large energy demand separately |
Write model numbers and connection types next to the figures so the same device is not counted twice. Adapter maximum watts may differ from average consumption.
A transparent worked budget
Suppose your measurements were 20W network power for ten hours (200Wh), 10W lighting for five hours (50Wh), and 600Wh of refrigerator energy during the planned period. The total would be 850Wh delivered to loads. These are hypothetical inputs, not household measurements or a recommended system size.
If you assumed 80% of nominal capacity reaches those loads, 850 ÷ 0.80 is about 1063Wh nominal before reserve. Replace that assumption with relevant evidence; do not apply it again if your budget already uses measured delivered Wh.
Check watts and startup independently
Add simultaneous running demand, then confirm appliance startup and station outlet limits. A 1500W resistive heater running for one hour consumes 1500Wh at the load even before conversion losses. Short periods of heating can dominate a small-device budget.
Do not assume boost output modes or a peak marketing figure support every compressor, pump or appliance. Use manuals and a supported pre-outage verification.
Account for recharge
Compare daily consumption with realistic mains, solar or vehicle replenishment under supported arrangements. Charging taper, weather, shade and limited access can reduce what you replace. Budget a missed charging window where continuity is important.
Document the completed plan
Keep the measured load list, usable-energy basis, reserve, supported cables, station operating limits and alternatives together. Follow food safety and medical-device guidance independently of the arithmetic. Home circuit integration requires approved equipment and a qualified electrician.
Sources and verification
- U.S. Department of Energy: estimating appliance energy use
- FDA: preparing for power outages with medical devices
- FoodSafety.gov: food safety during a power outage