CHAARM: A model to predict uncertainties in indoor pollutant concentrations, ventilation and infiltration rates, and associated energy demand in Chilean houses

Abstract

The housing stock of Chile is responsible for 15% of its total final energy consumption and so its Government is regulating the construction of dwellings. However, there is a need to establish models to help governments determine sensible guidance. This paper presents the Chilean Housing Archetypes AiR quality Model (CHAARM) and a stochastic framework for predicting uncertainties in indoor pollutant concentrations, ventilation and infiltration rates, and associated energy demand during the heating season. Pollutant sources are PM2.5 emitted by cooking and unflued heaters present in 80% of houses.CHAARM predicts that 66% of dwellings have a daily mean PM2.5 concentration below the WHO 24-hour guideline value of 25 μg/m3, even if their windows are always closed. Houses are not found to be airtight and 60% have Q50>10 m3 h−1 m-2. Dwelling ventilation and infiltration heat loss is estimated to be 0.25–42.3 MWh with 90% confidence, and to account for at least 15% of the estimated total energy demand of the stock. Therefore, many houses require remediation measures to improve their airtightness and to reduce their annual space heating demand. However, to avoid negative health effects from exposure to PM2.5, kitchen ventilation, such as a cooker hood, should be installed and unflued heaters should be replaced.