lämmönarvo

Lämmönarvo, also known as "heat value" or "caloric value," refers to the amount of heat energy released when a substance, typically fuel or food, undergoes complete combustion or metabolic processing. In the context of fuels, it quantifies the energy content per unit mass or volume, usually measured in kilojoules per kilogram (kJ/kg) or megajoules per cubic meter (MJ/m³). For food, it indicates the energy available for biological processes, commonly expressed in kilocalories (kcal) or kilojoules (kJ) per gram.

The term originates from Finnish, where "lämmö" means heat and "arvo" means value. In Finland, lämmönarvo is a widely used concept in discussions about energy efficiency, particularly in relation to wood fuels, bioenergy, and household heating. The measurement helps consumers and industries compare different energy sources based on their efficiency and cost-effectiveness.

For solid fuels like wood or peat, lämmönarvo is influenced by factors such as moisture content, density, and chemical composition. Higher moisture levels reduce the effective heat value because energy is used to evaporate water rather than generate heat. Similarly, food lämmönarvo varies depending on macronutrient content—proteins, fats, and carbohydrates each contribute differently to the total energy yield.

Accurate determination of lämmönarvo requires precise laboratory testing, often using a calorimeter, which measures the heat released during combustion. Standards and regulations ensure consistency in reporting values, enabling fair comparisons across products. In Finland, organizations like the Finnish Energy Agency (Energiavirasto) provide guidelines and data on lämmönarvo for various fuels to support informed decision-making in energy use.