Anyone rationing gas while camping or wondering whether the propane cylinder will last through a garden party faces a simple question: how many hours will this cylinder deliver energy? The gas consumption calculator answers this for propane, butane, and natural gas — taking calorific value, appliance output, and fill quantity into account. It also estimates heating costs when the annual consumption and current gas price are known.
Step by Step: How to Use the Gas Consumption Calculator
- Select the gas type: Propane (calorific value 25.9 kWh/kg), butane (28.7 kWh/kg), or natural gas (10 kWh/Nm³). Camping cartridges typically contain a butane-propane blend.
- Enter the appliance output: Found on the rating plate. Gas grill 3–5 kW, camping stove 1.5–2.5 kW, gas heating 8–24 kW, water heater 18–24 kW.
- Enter the fill quantity or usage time: Either the available gas quantity (kg for LPG, Nm³ for natural gas) for a runtime calculation — or the daily operating hours for an annual consumption figure.
- Enter the gas price (optional): Current propane bottle price approx. €1.20–1.60/kg; natural gas tariffs approx. €0.08–0.12/kWh depending on supplier and contract.
- Read the result: Consumption in kg/h or Nm³/h, cylinder runtime in hours, and estimated annual costs in euros.
Practical Examples
Example 1 – Garden party with gas grill: 4 kW grill, 11 kg propane cylinder (energy content: 11 × 25.9 = 284.9 kWh). Runtime = 284.9 ÷ 4 = 71 hours at constant full load — realistically 40–50 h, since the grill modulates and is used with the lid closed.
Example 2 – Camping weekend: Camping stove 2 kW, 230 g butane cartridge (6.6 kWh). Runtime = 6.6 ÷ 2 = 3.3 h of actual cooking time — enough for a weekend with economical use of about 20 minutes per meal.
Example 3 – Single-family home heating costs: Gas heating 15 kW, 1,800 full-load hours per year. Consumption: 15 × 1,800 = 27,000 kWh → 2,700 Nm³. At €0.10/kWh = €2,700/year in pure energy costs.
Gas Consumption and Cylinder Runtime
Propane cylinder 11 kg: 11 kg / 1.97 kg/m³ ≈ 5.6 Nm³. Grill 4 kW: 4 kW / (25.9 kWh/m³) = 0.154 m³/h → cylinder lasts approx. 36 hours of grilling. A 230 g camping cartridge lasts approx. 2–3 hours of cooking.
Frequently Asked Questions (FAQ)
Why does actual consumption differ from the calculation?
Appliances rarely run at continuous full load. A grill with the lid on, a thermostatically controlled stove, or a modulating boiler all consume significantly less than the rated output suggests. The calculator gives the theoretical maximum consumption.
How do I check the remaining content of a propane cylinder?
Propane cylinders can be weighed — the empty weight (tare) is stamped on the cylinder. Current weight minus tare = remaining content in kg. Another method: pour warm water down the outside; the gas-liquid boundary feels cooler to the touch.
Why does propane deliver more energy per litre than butane?
Actually, the reverse is true: butane has a slightly higher calorific value per kg (28.7 vs. 25.9 kWh/kg) and also per litre of liquid. Propane is nonetheless preferred for outdoor use because it remains liquid and vapourises down to −42 °C — butane fails near 0 °C.
