How Long Will It Run

Which power station will run a gas combi boiler?

A gas combi boiler draws about 85 W in the UK, for roughly 60% of the time — an average of 51 W. 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.

Specification

Running watts (UK 230 V)
85 W
Running watts (US 120 V)
85 W
Start-up surge
85 W
Duty cycle
60%
Average draw
51 W
Outlet
AC mains socket
Group
Heating
Energy for 8 hours
488 Wh delivered, needing about 672 Wh of rated capacity
Energy for 24 hours
1,464 Wh delivered, needing about 2,014 Wh of rated capacity

Typical figures for a typical unit, last reviewed 2026-08-29 — not a measurement of your appliance. Modelled on professional.vaillant.co.uk. Vaillant’s ecoTEC plus installation manual lists the 825, 832 and 835 combis at 35 W minimum, 80–90 W maximum and under 2 W on standby; the 838 peaks at 120 W. Worcester Bosch’s Greenstar 4000 ErP data gives 39 W at full load and 13 W at part load. The gas does the heating; this is only the fan, pump and controls. Measure your own.

What size power station do I need?

For 4 hours

Cheapest that does it: Bluetti AC50B — 5 h 26 min, £299 / $399

Lightest that does it: EcoFlow RIVER 2 Max — 6 kg

68 of 80 stations manage it.

For 8 hours

Cheapest that does it: Jackery Explorer 1000 v2 — 12 h 45 min, £419 / $549

Lightest that does it: EcoFlow RIVER Pro — 7.6 kg

60 of 80 stations manage it.

For 12 hours

Cheapest that does it: Jackery Explorer 1000 v2 — 12 h 45 min, £419 / $549

Lightest that does it: Jackery Explorer 1000 v2 — 10.8 kg

51 of 80 stations manage it.

For 24 hours

Cheapest that does it: Dabbsson DBS2300 — 26 h 28 min, £1,499 / $1,599

Lightest that does it: Dabbsson DBS2300 — 25 kg

15 of 80 stations manage it.

Every station ranked

79 of the 80 stations here can run a gas combi boiler at all. The longest is the Zendure SuperBase V6400 at 2 days 13 h; the shortest that manages it is the Bluetti AC2A at 2 h 31 min.

Every station, longest first. UK 230 V, new pack at 20 °C, 10% reserve
StationWhTypical runtimeNights (8 h)Indicative price£/hourkg
Zendure SuperBase V64006,4382 days 13 h7.6£3,699 / $3,999£60.9262
EcoFlow DELTA Pro Ultra6,1442 days 11 h7.3£4,999 / $5,799£85.0982.8
Jackery Explorer 5000 Plus5,0402 days 5 h6.6— / $3,499—61
Zendure SuperBase V46004,60847 h 10 min5.9£2,999 / $4,999£63.5853
Goal Zero Yeti PRO 40003,99342 h 4 min5.3— / $4,000—52.5
EcoFlow DELTA Pro 34,09641 h 56 min5.2£2,799 / $3,199£66.7551.5
Anker SOLIX F38003,84040 h 27 min5.1£2,999 / $3,499£74.1460
EcoFlow DELTA Pro3,60037 h 55 min4.7£2,499 / $2,699£65.945
Pecron E3600LFP3,07233 h 19 min4.2— / $999—36
Anker SOLIX F30003,07233 h 19 min4.2£1,899 / $1,999£56.9941.5
Bluetti AC300 + B3003,07232 h 22 min4£2,499 / $2,699£77.2263
Goal Zero Yeti 3000X3,03231 h 38 min4— / $3,000—31.7
Jackery Explorer 3000 Pro3,02431 h 33 min3.9— / $2,499—29
Bluetti Apex 3002,76429 h 59 min3.7£1,799 / $1,699£60.0137
Dabbsson DBS23002,33026 h 28 min3.3£1,499 / $1,599£56.6525
DJI Power 20002,04823 h 38 min3£1,299 / $1,399£54.9722
Bluetti Elite 200 V22,07323 h 32 min2.9£1,199 / $899£50.9324.5
OUKITEL BP20002,04823 h 16 min2.9£1,099 / $1,199£47.2525
UGREEN PowerRoam 22002,04823 h 16 min2.9£1,199 / $1,299£51.5525
Anker SOLIX C2000 Gen 22,04823 h 16 min2.9——18.9
Anker SOLIX C20002,04823 h 16 min2.9——24.5
EcoFlow DELTA 3 Max2,04823 h 16 min2.9£1,199 / $1,499£51.5520.3
Jackery Explorer 2000 v22,04223 h 11 min2.9£849 / $999£36.6117.5
Anker SOLIX F20002,04822 h 54 min2.9£1,499 / $1,599£65.4630
Bluetti AC200L2,04822 h 54 min2.9£1,299 / $899£56.7227.9
Bluetti AC200MAX2,04822 h 54 min2.9£1,399 / $1,199£61.0928.1
EcoFlow DELTA 2 Max2,04822 h 54 min2.9£1,199 / $1,399£52.3623
Jackery Explorer 2000 Plus2,04222 h 50 min2.9£1,999 / $1,999£87.5627.9
OUKITEL P2001 Ultimate2,00022 h 43 min2.8£999 / $1,099£43.9921.5
Pecron E2000LFP1,92021 h 48 min2.7— / $599—22
VTOMAN Jump 18001,54817 h 52 min2.2— / $999—17.5
VTOMAN FlashSpeed 15001,54817 h 52 min2.2— / $620—17
Pecron E1500LFP1,53617 h 43 min2.2— / $549—17.4
EcoFlow DELTA Max 16001,60217 h 14 min2.2——22
Bluetti AC2401,53617 h 10 min2.1£1,099 / $999£64.0133
Bluetti AC180P1,44016 h 37 min2.1£899 / $649£54.1216
Jackery Explorer 1500 Pro1,51216 h 31 min2.1— / $1,699—17
Goal Zero Yeti 1500X1,51616 h 19 min2— / $1,125—20.7
ALLPOWERS S2000 Pro1,45115 h 37 min2£899 / $549£57.5914.5
Jackery Explorer 1000 Plus1,26414 h 49 min1.9£549 / $999£37.0414.5
ALLPOWERS R15001,15213 h 17 min1.7£699 / $539£52.616.7
Bluetti AC1801,15213 h 17 min1.7£749 / $499£56.3616
Jackery Explorer 1000 v21,07012 h 45 min1.6£419 / $549£32.8610.8
Anker SOLIX C10001,05612 h 23 min1.5£699 / $799£56.4612.9
Dabbsson DBS1000 Pro1,02412 h1.5£599 / $619£49.9213.5
UGREEN PowerRoam 12001,02412 h1.5£649 / $699£54.0811.6
DJI Power 10001,02412 h1.5£749 / $799£62.4213
Anker SOLIX C1000 Gen 21,02412 h1.5——12
Bluetti Elite 100 V21,02412 h1.5£599 / $649£49.9211.3
EcoFlow DELTA 3 Plus1,02412 h1.5£599 / $799£49.9213.6
EcoFlow DELTA 31,02412 h1.5£649 / $649£54.0812.5
EcoFlow DELTA 21,02411 h 49 min1.5£549 / $699£46.4912
Goal Zero Yeti 100099811 h 42 min1.5— / $1,200—16
Anker SOLIX C800 Plus7689 h 9 min1.1——10.7
Bluetti AC707689 h 9 min1.1£449 / $359£49.0710.2
EcoFlow RIVER 2 Pro7689 h 9 min1.1£499 / $549£54.547.8
Bluetti EB70S7168 h 32 min1.1£449 / $429£52.649.7
UGREEN PowerRoam 6006808 h 14 min1£449 / $499£54.498.4
Goal Zero Yeti 7006778 h 12 min1— / $700—9.2
EcoFlow RIVER Pro7208 h 8 min1——7.6
Jackery Explorer 600 Plus6327 h 47 min1——7.3
DJI Power 5005126 h 12 min0.8£399 / $449£64.357.3
EcoFlow RIVER 3 Max5126 h 12 min0.8——6.6
EcoFlow RIVER 2 Max5126 h 12 min0.8£449 / $349£72.426
Goal Zero Yeti 5004996 h 2 min0.8— / $500—7.3
Jackery Explorer 5005186 h 2 min0.8— / $359—6
Bluetti AC50B4485 h 26 min0.7£299 / $399£55.066.5
Bluetti AC604034 h 53 min0.6£449 / $599£92.019.1
Bluetti Elite 30 V22883 h 46 min0.5£229 / $449£60.744.3
Goal Zero Yeti 3002973 h 40 min0.5— / $350—6.2
ALLPOWERS R6002993 h 37 min0.5£199 / $219£54.975.6
Jackery Explorer 300 Plus2883 h 37 min0.5£319 / $300£88.373.8
Anker SOLIX C3002883 h 33 min0.4£229 / $249£64.514.4
EcoFlow RIVER 3 Plus2863 h 28 min0.4£219 / $269£63.294.7
Bluetti EB3A2683 h 15 min0.4£199 / $219£61.234.6
Jackery Explorer 240 v22563 h 13 min0.4£209 / $249£65.113.6
EcoFlow RIVER 22563 h 9 min0.4£209 / $199£66.353.5
EcoFlow RIVER 32453 h 1 min0.4£169 / $179£55.963.6
Bluetti AC2A2042 h 31 min0.3£149 / $149£59.363.6
Anker SOLIX C300 DC288Too big———2.8

From the mains: what a gas combi boiler costs to run per hour, night and month.

Gear

Shop for a gas combi boiler

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Measure your own draw

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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).