Indoor air quality is a key aspect of people staying inside buildings. Combustion processes have been identified as one of the most important sources of pollutants in the indoor environment. Proper HVAC design must account for all sources and variations in their intensity, such as also the burning of candles, which produce not only increased amounts of carbon dioxide as a result of the combustion of the organic matrix, but also often dangerous organic substances. On the other hand, the candle burning represents an energy source as well. This article deals with the study of thermal decomposition of selected candle material using methods of thermal analysis - thermal gravimetric analysis (TG) and differential scanning calorimetry (DSC). The wax material analyzed was identified as a mixture of palm stearin and paraffin. During the candle wax material heating, the energy up to 772.6 J per 1 g of material can be released in dependence on the heating rate.

In construction, the emphasis is currently on high energy efficiency of buildings. A ventilation system ensuring the indoor air quality has a significant share of energy consumption in buildings. Open fire sources, such as gas stoves and candles result in the air pollution in the indoor environment that causes more intensively operation of ventilation systems. The aim of this research is to quantify the pollutants arising from the burning of a randomly selected wax candle that commonly is used in households. Experimental measurements were performed with a special regard to carbon dioxide (CO2) production. The weight loss of the wax during the burning of the candle was has been measured and subsequently the production of CO2 was estimated using a chemical formula. Based on the amount of CO2 produced, the intensity of air exchange using ventilation system has been calculated to achieve the required quality of the indoor environment. The calculated air volume flow rate required to remove the pollutants generated during the burning of the candle is in this case approximately 54% of the air volume flow required per one person.