# Propane versus butane



## 97201 (Jan 7, 2006)

Disregarding temps for the moment, I have an Extendastay fitted to my ARV. Without any real evidence, it seems that LPG produces more heat faster than Butane. In as much as, my bottle was running low this morning, so I switched it over to LPG, and within 15mins, I was as warm as toast. Where as in the past it has taken about half an hour min on butane just to be comfortable.

Does propane/LPG produce more BTU than butane *or* is it a temperature thing?

Ian
Three Green


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## Fatalhud (Mar 3, 2006)

I think LPG is a blend of propane and butane which may make a difference
I was always told to use butane (blue) in summer as propane (Red) caused sooting of the jets in appliances
And use propane in winter because it copes with lower temperatures

Must admit got it wrong way round this year and bought a new blue for winter (muppet)

Im sure someone with more knowledge will come along and help with a more technical answer and also confirm or dispel my myths

Alan H


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## DABurleigh (May 9, 2005)

"so I switched it over to LPG, and within 15mins, I was as warm as toast. Where as in the past it has taken about half an hour min on butane just to be comfortable."

As far as the above goes (ie significant difference) this would have been due to the lower vapour pressure of Butane when it is colder. The ambient temperature can be way above the 4degC critical temperature for Butane, but the bottle cools as gas is drawn off. 

Dave


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## 97201 (Jan 7, 2006)

Scuse for being a thicko, but I seem to get more heat (per unit or minute?) from LPG. I know that butane 'aint good below 5c as I wake up with freezing extremities (fingers and toes you lot), but per unit, is propane more efficient? I knew I would ask the right question in the end!

Ian


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## Fatalhud (Mar 3, 2006)

Found this on Calor site

What is the Calorific value of LPG? 
Commercial Propane = 13.83 kWh/kg
Commercial Butane = 13.62 kWh/kg

Not much difference 

Alan H


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## DABurleigh (May 9, 2005)

It depends on the "unit", Ian. Your call 

Dave


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## Fatalhud (Mar 3, 2006)

Not as cold as you think
More from Calor

What is the operating temperature range for each of the gases?
BS 5482 part 1 states: "For Butane cylinders, satisfactory service might not be obtained at a temperature of less than *10*°C; the most suitable temperature range is from 13 to 30°C. For temperatures less than 13°C, the use of propane should be considered."

Link below helpfull

http://www.calor.co.uk/faq/index.htm

Alan H


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## Guest (Jan 29, 2008)

Fatalhud said:


> I was always told to use butane (blue) in summer as propane (Red) caused sooting of the jets in appliances
> And use propane in winter because it copes with lower temperatures
> 
> Alan H


I come from canal boating. Propane is used on boats almost universally summer or winter. I think this because many boats are used in the winter for the odd day/weekend away. Provided you have the correct regulator it will burn very satisfactorily. The jets remain the same for either gas.

Tco


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## pippin (Nov 15, 2007)

LPG = *L*iquified *P*etroleum *G*as

A generic term for a specific family of gasses which are manufactured as one of the by-products of the distillation of black crude oil into a myriad of other products. Notably petrol, diesel & etc.

The most common LPGs are butane and propane. There are others. It is not practicable to separate them all from each other.

In practice it means that your cylinder of "butane" is mostly butane, but does contain other gasses, notably some propane.

Likewise "propane" will contain some butane and other gasses.

It is not correct to distinguish between propane and butane by calling one of them LPG! They both are!

The confusion arises especially at garages which call whatever comes out of their tank "LPG" ("GPL" in French). It is simply because the initials are short and concise.

They can hardly have a notice big enough to describe their product as
"variable proportion of butane and propane (plus traces of other gasses) which depend on the season (because butane doesn't evaporate in the cold) and on how much we paid for the stuff because we got it cheaper due to the lower specification"!!


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## Saxonman (Aug 23, 2007)

Propane does have a higher calorific value than butane which I seem to recall is why, in the same size bottles, Calor supply 6kg propane against 7kg butane and 13kg propane against 15kg butane. However I can't explain why propane is regulated at 37mb against 28mb for butane (except in newer vans). Anyway propane seems to be taking over judging by the blue bottles oversprayed red.

Bob


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## 97201 (Jan 7, 2006)

Final question as it's only 3.2c outside at the mo' and I'm b****y freezing again.

On butane the hot air furnace only runs for about 2/3 mins (at this temp) before shutting down although the blower keeps going. The hob and hot water boiler don't seem to be affected and still run.

Is it because the hot air system draws a lot more gas?

Ian
Three Green


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## DABurleigh (May 9, 2005)

Ian - yes, though you are luck the boiler still does.

Bob "Propane does have a higher calorific value than butane" - not volume-for-volume, hence my asking Ian to expand on his question 

Dave


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## 97201 (Jan 7, 2006)

Thanx all.

Just going outside to swop to the last dribble of LPG (bought in the UK)

Quote: I may be some time........................................................


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## DABurleigh (May 9, 2005)

From what - LPG?


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## 97201 (Jan 7, 2006)

Butane

Ian


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## ianhibs (May 1, 2005)

Hi

This is very interesting. I have one refillable bottle full of Butane purchased in Spain thanks to the MHF database. My other cylinder is Repsol Propane. We're in Salamanca right now where it's warm during the day but "brass monkeys" at night. Having read all this, I think I'll switch to the propane tonight although , to be fair, I've had no problem with the butane.

Ian


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## sergeant (Jun 7, 2006)

Hi Ian & all, The second main advantage to Propane over Butane is what is called "The off take rate". In plain English the amount of gas that can be produced from the liquid at any one time. This is relevant to surface area & anbient temperature. To give you an idea about it a 7kg Butane can produce 7kw per hour at 15 deg C whereas a 6kg Propane produces 11kw in the same conditions. A 15kg Butane is 9.9kw whereas a 13kg Propane produces 15kw..As the anbient temperature drops Butane's ability to produce vapour drops rapidly. This is also the main reason why you should never wrap a bottle as the chemical reaction needs to draw heat from outside the bottle. A furnace in an American van can run anywhere between 4 & 16kw. English vans normally need a max of 4kw. Hope this hasnt confused anyone, Steve


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## ianhibs (May 1, 2005)

No confusion Steve and, having read that, I am glad I switched to Propane last night There were icicles hanginc off the van this morning.

Spain is a cold country with a hot sun. And when the sun's not out-Brrrr.

Ian


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## 97201 (Jan 7, 2006)

I'm glad I asked the question as I have learnt so much from you chaps (and chappesses) with all your excellent input  

Another point springs to mind from last night's experience. I am still on butane until at least Sunday when I hope to pick up a propane bottle at a flea market (thanks C7KEN). But to get to the point. I connected up a full bottle and it ran well, cutting in and out all night as I should. It would appear that the problem starts when the bottle is only about a quarter full.

Why is that?

Ian
Three Green


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## DABurleigh (May 9, 2005)

Because using the gas cools it. The less of it is to cool, the colder it gets. The colder it gets, the less it is willing to provide gas.

I regularly used a Camping Gaz 907 cylinder in cooler weather for BBQs. The less gas in the cylinder the earlier I had to stand it in a bowl of hot water.

Dave


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## wobby (May 1, 2005)

All domestic heating systems that includes Aga, Rayburn, & the Irish made Stanley central heating ranges that use LPG use only Propane summer and winter. However LPG at the garage can be a mixture of the Butane and propane. So beware if you use refillable cylinders in very cold weather you may have problems, in fact Dometic advise against refillable cylinders. 

Wobby


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## 97201 (Jan 7, 2006)

Dave, Thanks

Wobby, these sre replacement bottles.

Ian
Three Green


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