Scenarios › Power station for partial-home backup (essentials circuit)
What size power station for partial-home backup?
The essentials circuit: fridge, sump pump, furnace blower, lights, and internet — the loads a transfer switch usually feeds. The furnace blower’s startup surge dominates the inverter requirement. Here is the size that carries an essentials panel through a multi-hour outage, with expandable picks for longer.
6,516 Whcapacity needed
1,870 Wrunning watts
3,420 Wsurge to clear
8.0 hruntime horizon
This load: Refrigerator (modern) · Sump Pump (1/3 HP) · Gas Furnace Blower (1/2 HP) · LED Lights (10 bulbs) · WiFi Router + Modem. Want to tweak it? Open the full sizing tool and adjust the appliances and hours.
What size you need
This is a big load — about 6,516 Wh over 8.0 h. No single portable battery holds that much, but the expandable systems below meet the power draw (1,870 W running, 3,420 W surge) — add a battery module to reach the full watt-hours. This is the expandable-system territory most partial- and whole-home backup lives in.
The math
Running watts (everything on at once) = 1,870 W
Surge watts (worst single startup + the rest running) = 3,420 W
Average draw (cyclic loads counted by their duty cycle) = 733 W
Watt-hours = 733 W × 8.0 h ÷ 90% usable reserve = 6,516 Wh
1
Zendure SuperBase V6400best expandable match
6,438 Wh 3,800 W cont · 5,000 W surge expandable ~7.9 h on this load $$$
First Zendure entry — a 6.4 kWh, 3,800 W whole-home-class unit on semi-solid-state cells (3,000+ cycles), expandable to 64 kWh with satellite battery packs.
Semi-solid-state LiFePO4 · ~2 h to full at 3,600 W AC input; up to 3,000 W solar · 130 lb
2
EcoFlow DELTA Pro Ultra
6,144 Wh 7,200 W cont · 10,800 W surge expandable ~7.5 h on this load $$$
EcoFlow's flagship whole-home system above the DELTA Pro and DELTA Pro 3 — base unit is inverter (70 lb) + battery (111.8 lb), expandable to 30 kWh with one inverter stack and 90 kWh with three.
LiFePO4 · 8,800 W combined AC+solar fast charge (two batteries full in ~2 h); 5.6 kW max solar input · 182 lb
3
Jackery Explorer 5000 Plus
5,040 Wh 7,200 W cont · 14,400 W surge expandable ~6.2 h on this load $$$
The largest single Jackery unit — 120/240V split-phase output makes it a real panel-level whole-home contender, not just a big portable.
LiFePO4 · True 120V/240V split-phase output; expandable to 60 kWh with additional battery packs and units · 135 lb
4
EcoFlow DELTA Pro 3
4,096 Wh 4,000 W cont · 8,000 W surge expandable ~5.0 h on this load $$$
A 4 kWh, 4,000 W (120/240 V) system built specifically for whole-home backup.
LiFePO4 · AC/solar/EV; expandable to 48 kWh · 113 lb
5
Goal Zero Yeti PRO 4000
3,993 Wh 3,600 W cont · 7,200 W surge expandable ~4.9 h on this load $$$
Goal Zero’s LiFePO4 flagship — 4 kWh, 3,600 W, whole-home with the transfer switch and tanks.
LiFePO4 · Fast AC; expandable to ~27 kWh · 104 lb
6
Anker SOLIX F3800
3,840 Wh 6,000 W cont · 9,000 W surge expandable ~4.7 h on this load $$$
A 6,000 W, 240 V system for whole-home backup including a well pump and electric range, expandable to ~27 kWh.
LiFePO4 · 120/240 V; expandable to 26.9 kWh · 132 lb
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Disclosure.
The load, appliance by appliance
| Appliance | Running | Surge | Duty | |
|---|
| Refrigerator (modern) | 150 W | 1,200 W | 35% | size on its own → |
| Sump Pump (1/3 HP) | 800 W | 1,500 W | 20% | size on its own → |
| Gas Furnace Blower (1/2 HP) | 800 W | 2,350 W | 50% | size on its own → |
| LED Lights (10 bulbs) | 100 W | — | 100% | |
| WiFi Router + Modem | 20 W | — | 100% | |
⚡ Informational only — a computed sizing estimate from published appliance-wattage charts and manufacturer station specs. It is not an electrical guarantee. For hardwired or whole-home backup, transfer switches, or any permanent install, consult a licensed electrician. Appliance wattages are representative chart values and vary by model; check your nameplates. Duty cycle (how much of the time a load actually draws) is how we keep the watt-hour estimate from overselling capacity.
Common questions
What size power station for partial-home backup?
For Refrigerator (modern), Sump Pump (1/3 HP), Gas Furnace Blower (1/2 HP), LED Lights (10 bulbs), WiFi Router + Modem over 8.0 h you need about 6,516 Wh — more than a single portable battery holds. Use an expandable system that meets the 3,420 W surge (like the Zendure SuperBase V6400) and add a battery module to reach the full capacity.
How many watt-hours does this load need?
About 6,516 Wh for 8.0 h — we take the duty-weighted average draw (733 W, since cyclic loads like fridges and pumps don't run constantly), multiply by the hours, and divide by a usable-capacity reserve. Running watts are 1,870 W; surge is 3,420 W.
Other scenarios
Sources: appliance wattages — standard appliance/generator sizing charts; station specs — manufacturer published specifications (compiled 2026-10-05; approximate). Informational only — a computed sizing estimate from published appliance-wattage charts and manufacturer station specs. It is not an electrical guarantee. For hardwired or whole-home backup, transfer switches, or any permanent install, consult a licensed electrician.