This study provides novel observations and insight into the chemical composition of indoor air. Utilizing state-of-the-art semi-volatile thermal-desorption aerosol gas chromatography (SV-TAG) we present, for the first time, hourly concentrations and partitioning of semivolatile organic compounds (SVOC) measured in a single-family house in California during normal occupancy. Time series of indoor SVOCs were characterized by temperature-dependent elevated background levels for a broad suite of chemicals, underlining the importance of continuous emissions from static indoor sources, i.e. building materials and interior contents. However, the highest SVOC concentrations were observed during episodic enhancements associated with occupant activities.