Table 1: Characteristics of the 78 dwellings where study participants lived between November 2011 and November 2012
CharacteristicMean ± SD*
Years since dwelling was built19.3 ± 8.2
Heating method, no. (%)
Forced air70 (90)
Radiator8 (10)
Dwelling occupancy
No. of occupants6.1 ± 3.0
No. of people per room†1.1 ± 0.5
Overcrowded,‡ no. (%)39 (50)
Ventilation
Air changes per hour
    With heating off
        Living area0.67 ± 0.28
        Bedrooms0.31 ± 0.28
    With heating on
        Living area1.69 ± 0.26
        Bedrooms1.29 ± 0.29
Volume of room, m3
    Living area67.9 ± 9.4
    Bedrooms27.7 ± 4.4

Note: SD = standard deviation.

*Except where noted otherwise.

†Calculated by dividing the number of occupants by the total number of rooms in the dwelling.

‡Occupancy exceeding 1 person per room.22