Hi everyone, any ideas please. I drive a van conversion that can only carry 2 * 4.5 kg butane, or 2* 3.9kg Propane, both bottle dimensions are the same, but missus informs me that butane weighs more, " ex chemist". I have always tended to just use the propane as it is better in colder weather, but my questions are;. Should I switch over to butane for the summer months, or just stay with the propane. I'm assuming the actual volume of gas is the same in each cylinder, just the weight difference being attributable to butane being heavier. I think I have just answered the question, but is it an item that anyone has looked at previously. The more modern van conversions now carry 2* 6kg propane, most of them located under the sink space which I currently have as cupboards only. Many thanks for your thoughts opinions.