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Table 1 Experiment 1: Ventilation estimated using different methods in two identical houses

From: Measuring ventilation in different typologies of rural Gambian houses: a pilot experimental study

Method Day Time of recordings n House t p
House 1 Mean ACH m3/h (95% CI) House 2 Mean ACH m3/h (95% CI)
Method A: Fan pressurization (blower door test) 1 02.00 h, 06.00 h, 10.00 h, 14.00 h, 18.00 h and 22.00 h 5 71.6 (69.0, 74.3) 85.2 (80.6, 89.9) − 15.2 <0.001
Method B: Artificial CO2 elevation and decay 1 04.00 h, 08.00 h, 12.00 h, 16.00 h, 20.00 h and 00.00 h 5 − 33.2 (− 51.6, − 14.8) − 29.9 (− 47.2, − 12.7) − 0.421 0.695
Method C: Natural CO2 elevation and decay* 2–7 09.00–17.00 h 6 − 28.0 (− 46.6, − 9.5) − 20.5 (34.1, − 6.9) − 1.040 0.346
Method D: Natural CO2 rise 2–7 21.00–06.00 h 6 14.8 (12.1, 17.5) 13.2 (12.1, 14.4) 1.465 0.203
Method E: Hot wire thermo-anemometer 2–7 21.00–06.00 h 6 n/a n/a
  1. ACH air exchange per hour, CI confidence intervals
  2. * First 15 min after human subjects have entered the house