We made a questionnaire survey with a view to clarifying the residential status quo as regards airtightness and ventilation. To be more specific, the state of ventilation in connection with cooking was mainly researched. In other words, 1) how ventilation was effected, 2) To what extent the residents were conscious of the air flow as well as smell indoors. The ventilation fan with hood for a cooking range was installed in more than 90% of the houses surveyed, and this system was highly frequently used while cooking. In many houses, however, the residue of the cooking smell had stayed after the ventilation fan was stopped, and the residents expressed unpleasantness toward the lingering smell far more than the cooking smell. Apart from the measure to counter the residue smell, there is a need to pay more attention to servicing the ventilation system as the air intake tended to be reduced in many households on account of the poorly serviced fan.