A very frequently asked question is:  how many hours does the stove work on one gas cylinder  most common in Poland, i.e. 11 kg? If you are not curious, then immediately look at the table below the article.

The calculation is very simple. Because the descriptions are different and there are a lot of editors who when creating websites, it is not known why they do not enter SI units, but still enter kcal / h or MJ as the power unit. Most people are not careful in school lessons and do not really distinguish what work is from what it is power, and here they give different units, and how to figure it out, not to mention their conversion. And the editors also had it in elementary school.

I would like to explain that the SI system of measurement units has been functioning in Poland for some time. 1 kW is a unit of power and 1 kW * h is a unit of work performed. Therefore, we will stick to kW * h? An additional reason is that when we get a bill from an energy company, we have a given price for 1 kW * h. It seems easy to compare the price of different energy sources and that is why the EU forced all countries to include the price for the transmission on all bills, and at the end we do not know how much 1 kW * h of energy sent to us costs. We will stick to that, which is kW * h. In addition, we will use kilograms when it comes to LPG. After burning 1 kg of butane, we will get 13.64 kWh of energy, and after burning propane, we will get 13.99 kWh of energy. The most common LPG mixture sold in cylinders is mixture B. According to the Polish standard, it contains from 18 to 55% of propane.So how do we know what gas we buy from the seller? I can assure you that we do not know. Who knows? A gentleman who, pretending to be a professional, says that he has gas from a reliable source and that the mixture is 70% butane and 30% propane. I can assure you that he doesn’t know either. For the sake of simplicity, so as not to circle the reader any longer, we will assume that the calorific value of propane-butane is average, i.e. the mixture is 50/50. And it is 13.81 kWh / kg.

Now, calculating how much work there is in this cylinder that we buy at a distribution point or gas station. We multiply 13.81 * 11 = 151.91 kWh of energy.

Gas convector power (kW)Number of hours of work on 1 11 kg cylinder

In order for gas convectors with a capacity of 7.5 kW and above to function correctly on an 11 kg gas cylinder, it is recommended to use a second cylinder and connect them in a cascade. This is because as the gas in the cylinder runs out, the amount of gas evaporated decreases and this can cause the gas heater to turn off. According to the regulations, no more than two 11 kg cylinders should be used in one room. You can connect more than 2 11 kg cylinders in the battery or 33 kg cylinders and place them outside.