How Long Will It Run

How long will a Goal Zero Yeti PRO 4000 run a gas combi boiler?

About 1.8 days — 42 h 4 min typically, from 39 h 35 min in the worst case to 44 h 32 min at best. That assumes a gas combi boiler pulling 85 W for 60% of the time (average 51 W), plus the station's 18 W AC mains socket overhead — 69 W in total out of 2,902 usable watt-hours.

The gas makes the heat, so a battery only has to run the fan, pump and controls. Most boilers are wired into a fused spur rather than a plug, and some will not light on a station’s ungrounded output — read the boiler guide before relying on it.

Before you rely on it

The battery is the easy part. Most boilers are wired into a fused spur with no plug, and some will not light on a station's floating output because they sense the flame through earth. The boiler guide explains both problems and who can fix them.

The numbers

Goal Zero Yeti PRO 4000 · 3,993 Wh · new pack at 20 °C, 10% reserve
SetupAverage drawCautiousTypicalBest case
1 × gas combi boiler, UK 230 V69 W39 h 35 min42 h 4 min44 h 32 min
2 × gas combi boiler, UK 230 V120 W22 h 46 min24 h 11 min25 h 37 min
1 × gas combi boiler, US 120 V69 W39 h 35 min42 h 4 min44 h 32 min
  • 5.3 nights of eight hours, or 1.75 days of continuous running.
  • Usable energy: 2,902 Wh of the 3,993 Wh on the box, after chemistry, inverter losses and the reserve.
  • To keep it going for a full 24 hours you would need about 2,279 Wh of rated capacity — which this station has.
  • Start-up: the gas combi boiler asks for 85 W at switch-on against this station's 7,200 W peak — comfortable.

Buy the Goal Zero Yeti PRO 4000

Where to buy

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If this is for a power cut

Heating is what a battery does worst. In a power cut, warming people rather than rooms goes much further, and none of this needs a socket.

Without a power station: a 20,000 mAh power bank runs a USB heated throw for about 7 h 24 min. See the power bank numbers.

Hot water bottle and a vacuum flask. Boil water while you still can, keep it hot in a flask, and refill the bottle through the night.

Look for: A bottle made to BS 1970 in the UK, and a flask of a litre or more.

Hand warmers. Air-activated packs give hours of heat with no power at all, and a pocketful helps children and older relatives.

Look for: Long-duration packs, and the expiry date on bulk boxes.

Battery carbon monoxide alarm. Anything burning fuel indoors, a boiler relit after an outage included, can produce carbon monoxide you cannot see or smell.

Look for: A sealed long-life battery and EN 50291 certification in the UK (UL 2034 in the US).

Amazon links are affiliate searches for a type of product, not endorsements of a model; the site may earn a commission at no extra cost to you.

More: How to keep warm in a power cut, and the power cut essentials list (US edition).

What changes the answer

If instead…Typical runtimeChange
The pack is two years old38 h 41 min-8%
The pack is five years old33 h 39 min-20%
It is −10 °C outside35 h 45 min-15%
You run it flat, no reserve46 h 44 min+11%
You keep 20% back37 h 23 min-11%

If you need it to run longer

Nothing in this catalogue runs a gas combi boiler for twice as long as the Goal Zero Yeti PRO 4000. Either it is already near the top of the range, or this appliance is beyond what portable batteries do well — see the gas combi boiler page for the full ranking.

Smaller options that still work

StationWhTypicalWeightIndicative price
Anker SOLIX F38003,84040 h 27 min60 kg£2,999 / $3,499
EcoFlow DELTA Pro3,60037 h 55 min45 kg£2,499 / $2,699
Anker SOLIX F30003,07233 h 19 min41.5 kg£1,899 / $1,999
Pecron E3600LFP3,07233 h 19 min36 kg— / $999