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Propane or butane BBQ

Updated: 23 October 2026

You are choosing a bottle for a gas barbecue that lives outside in a UK garden, including evenings near freezing. Propane or butane is the decision, and the regulator has to match the gas. This page does not rank the nine trolleys. The [black gas BBQ comparison](/hub/grills-and-barbecues/black-gas-bbq) does that. The clip is on [gas BBQ hose and regulator](/hub/grills-and-barbecues/black-gas-bbq/sub/black-gas-bbq-hose-and-regulator). Peter F. used the GOV.UK cylinder pressures and Calor’s boiling points on 20 October 2026. This is not a timed cook. A qualifying purchase can earn a commission at no extra cost to you.

You are choosing a bottle for a gas barbecue that lives outside in a UK garden, including evenings near freezing. Propane or butane is the decision, and the regulator has to match the gas.

Our top picks

CosmoGrill CosmoGrill Pro Deluxe 6+1 with cover

Best overall

CosmoGrill CosmoGrill Pro Deluxe 6+1 with cover
9.0/10about £299.99
View offer
CosmoGrill CosmoGrill Original 4+1

Best value

CosmoGrill CosmoGrill Original 4+1
8.8/10about £199.99
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CosmoGrill CosmoGrill Emberr 6+1

Alternative

CosmoGrill CosmoGrill Emberr 6+1
8.0/10about £279.99
View offer
On this page
  1. 1.Why outdoor barbecues are sold on propane
  2. 2.37 mbar and 29 mbar
  3. 3.What the black gas BBQs in this set ask for
  4. 4.How big a bottle, as a rule of thumb

Why outdoor barbecues are sold on propane

Propane vaporises at about −42°C. Butane vaporises at about −2°C. Below that, a butane bottle can feel heavy while the burners starve, which is why Calor points outdoor cooking at propane. A UK garden in April can sit around that butane threshold. Butane is not illegal: on a warm afternoon it will run a barbecue whose jets are meant for butane. Do not warm a butane bottle with a flame. A refillable cylinder feeds the appliance through a regulator. That is the point of regulation 14(3) of the Gas Safety (Installation and Use) Regulations 1998. The choice here is which gas you are buying.

37 mbar and 29 mbar

GOV.UK puts nominal propane for a cylinder appliance at 37 mbar, Group P, and nominal butane at 29 mbar, Group B. Millibar is the pressure the regulator delivers, not a heat setting. A 37 mbar propane regulator on butane, or a butane regulator on propane, is the wrong pair. Some CosmoGrill bullets still print 28 mbar for butane beside 37 mbar for propane. That 28 is what the product page says. Quote both, and do not silently correct the listing to 29. If the data plate says 28 mbar butane, the regulator has to match the plate. If it says 37 mbar propane, a butane regulator is the wrong part. A regulator with no gas name and no millibar mark is an unlabelled joint. One Pro Deluxe review found an old lower-pressure set was the wrong input.
CosmoGrill CosmoGrill Pro Deluxe 6+1 with cover

Testsieger

CosmoGrill CosmoGrill Pro Deluxe 6+1 with cover
9.0/10about £299.99
View offer

What the black gas BBQs in this set ask for

These nine pages do not ask for one bottle. The Emberr included line is a propane hose and a clip-on regulator. The Platinum bullet says a clip-on propane hose at 37 mbar. Both Pro Deluxe bullets say the hose is not included and name 37 mbar propane or 28 mbar butane. You buy the regulator for one gas, not a single regulator for whichever bottle is in the garage. The Campfire and the Original 4+1 leave the hose as a separate purchase. The Weber Q included line does not name a gas. One of four UK reviews says canisters lasted about three hours. That is one cook, not a reason to copy a Pro Deluxe millibar onto a Weber.

How big a bottle, as a rule of thumb

BBC Gardeners’ World suggests about 5 kg for one to three burners, and at least 10 kg, often 13 kg, for five or more, plus a rough “about ten cooks” from a 5 kg bottle. That is a buying-article rule of thumb, not a weigh-in of these trolleys. Calor’s green patio gas is propane in 5 kg and 13 kg bottles with a 27 mm clip-on. Red screw-in propane is a different fitting. Butane bottles, including Campingaz-style cylinders, are another column. A 37 mbar propane regulator is the outdoor default when the plate says propane, and the wrong default when the plate says butane. Lighting and shutdown are on how to use a gas BBQ.

Common questions

Is propane or butane better for a UK garden?
Propane, if the barbecue will be used when the air can fall to around freezing. Calor puts propane’s vaporisation at about −42°C and butane’s at about −2°C. Butane still runs on a warm day if the regulator and the jets are the butane set. It is a poor winter bottle. The regulator has to match whichever gas you pick.
What is patio gas?
In Calor’s range it is propane in a green bottle, sold for appliances such as barbecues, in 5 kg and 13 kg sizes, with a 27 mm clip-on. It is not the same fitting as a red screw-in propane cylinder. A patio-gas regulator does not belong on that red valve.
Will butane work on a cold evening?
It gets unreliable as you approach about −2°C, because that is the vaporisation temperature Calor quotes. The bottle can still feel heavy while the burners starve. Propane is the gas Calor recommends for outdoor use for that reason. Do not heat a butane bottle to force it.
Why does the listing say 28 mbar if the official table says 29?
Because that is what the CosmoGrill Pro Deluxe bullets print for butane, beside 37 mbar for propane. GOV.UK’s nominal butane figure is 29 mbar. Keep both. Match the regulator to the plate and the gas you connect, and do not rewrite the product page so the numbers look tidy.
Can one regulator feed both gases?
No. Propane at 37 mbar and butane at the butane pressure are different regulators in Calor’s own split, and a clip that fits a green patio bottle does not fit every other cylinder. Buy the regulator for the gas on the data plate.
Does the Weber Q use the same bottle as a trolley?
The Q listing does not name a bottle. One UK review mentions canisters lasting about three hours, which is not a specification. A Pro Deluxe bullet that offers 37 mbar propane or 28 mbar butane is that listing’s sentence, not the Q’s. Read the Q manual or data plate before you share a regulator with a six-burner trolley.

Related pages

Gas regulator

Black gas BBQ

Best black gas BBQ: the listing that fits your patio

Gas BBQ buying guide: burner count and patio width

Gas BBQ hose and regulator: which boxes include it

How to use a gas BBQ: light, leak check, shut down

Sources

Public UK sources used for this comparison. Listing prices, stars and review counts are the amazon.co.uk figures for these ASINs. Retrieved 20 October 2026.

  1. GOV.UK: gas types and supply pressures (retrieved 20 October 2026)
  2. GOV.UK: fire safety outdoors (retrieved 20 October 2026)
  3. London Fire Brigade: barbecue safety leaflet, April 2024 (retrieved 20 October 2026)
  4. BSI: BS EN 498:2012 outdoor LPG barbecues (retrieved 20 October 2026)
  5. Calor: gas bottles for a barbecue (retrieved 20 October 2026)
  6. Calor: which hose and regulator (retrieved 20 October 2026)
  7. Gas Safe Register: barbecue safety (retrieved 20 October 2026)
  8. Weber UK: barbecue safety (retrieved 20 October 2026)