The Effect of Opening Windows on Air Change Rates in Two Homes

Howard-Reed, Cynthia; Wallace, Lance A.; Ott, Wayne R.

doi:10.1080/10473289.2002.10470775

Cited by 185 publications

(113 citation statements)

References 2 publications

Supporting

Mentioning

101

Contrasting

Unclassified

Order By: Relevance

“…A simple regression on wind speed while keeping the indoor -outdoor temperature difference < 28C ( with attic fan off and windows closed ) resulted in a very small coefficient of 0.03 h À 1 / m /s with only marginal significance ( P= 0.06). The finding of little or no effect of wind was also recently reported (Howard -Reed et al, 2002 ) for both this Virginia house and also a house in California. It may be that the generally tighter construction of homes and the use of vapor barriers have reduced the effect of wind speed and direction on residential air change rates compared to earlier studies.…”

Section: Effect Of Temperature and Windsupporting

confidence: 81%

“…However, based on an earlier study (Howard -Reed et al, 2002 ) that concluded that opening a single window as little as 10 -15 cm produced an air change rate of > 0.5 h À 1 , and the finding from this study that meteorological conditions alone could not account for air change rates >0.8 h À 1 , it is possible to attribute air change values > 0.8 h À 1 either to open windows or use of exhaust fans. Also, since a record of the attic fan use was kept, it is possible to differentiate between high air change rates caused by the attic fan and those caused by open windows.…”

Section: Effect Of Opening the Windowsmentioning

confidence: 54%

“…The normal practice was to open windows wide. An earlier study of the effect of window opening in this house had determined that opening windows wide (>30 cm ) led to an increase in the air change rate on the order of 0.5 h À 1 ( Howard -Reed et al, 2002 ).…”

Section: Methodsmentioning

confidence: 92%

“…An early study of 28 homes in England (Dick, 1950) developed some relationships with wind speed and temperature, and also included some qualitative effects of window -opening behavior based on questionnaires of residents. One recent study has provided quantitative information on the effect in two homes of opening windows to measured widths (Howard -Reed et al, 2002), but may have lacked sufficient measurements to derive a robust relationship with temperature and wind.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Continuous measurements of air change rates in an occupied house for 1 year: The effect of temperature, wind, fans, and windows

Wallace

Emmerich

Howard-Reed

2002

J Expo Sci Environ Epidemiol

228

139

View full text Add to dashboard Cite

A year -long investigation of air change rates in an occupied house was undertaken to establish the effects of temperature, wind velocity, use of exhaust fans, and window -opening behavior. Air change rates were calculated by periodically injecting a tracer gas ( SF 6 ) into the return air duct and measuring the concentration in 10 indoor locations sequentially every minute by a gas chromatograph equipped with an electron capture detector. Temperatures were also measured outdoors and in the 10 indoor locations. Relative humidity ( RH ) was measured outdoors and in five indoor locations every 5 min. Wind speed and direction in the horizontal plane were measured using a portable meteorological station mounted on the rooftop. Use of the thermostat -controlled attic fan was recorded automatically. Indoor temperatures increased from 218C in winter to 278C in summer. Indoor RH increased from 20% to 70% in the same time period. Windows were open only a few percent of the time in winter but more than half the time in summer. About 4600 hour -long average air change rates were calculated from the measured tracer gas decay rates. The mean ( SD ) rate was 0.65 ( 0.56 ) h À 1 . Tracer gas decay rates in different rooms were very similar, ranging only from 0.62 to 0.67 h À 1 , suggesting that conditions were well mixed throughout the year. The strongest influence on air change rates was opening windows, which could increase the rate to as much as 2 h À 1 for extended periods, and up to 3 h À 1 for short periods of a few hours. The use of the attic fan also increased air change rates by amounts up to 1 h À 1 . Use of the furnace fan had no effect on air change rates. Although a clear effect of indoor -outdoor temperature difference could be discerned, its magnitude was relatively small, with a very large temperature difference of 308C (548F ) accounting for an increase in the air change rate of about 0.6 h À 1 . Wind speed and direction were found to have very little influence on air change rates at this house.

show abstract

Section: Effect Of Temperature and Windsupporting

confidence: 81%

Section: Effect Of Opening the Windowsmentioning

confidence: 54%

Section: Methodsmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Continuous measurements of air change rates in an occupied house for 1 year: The effect of temperature, wind, fans, and windows

Wallace

Emmerich

Howard-Reed

2002

J Expo Sci Environ Epidemiol

228

139

View full text Add to dashboard Cite

show abstract

“…In most cases, the available data represent buildings with closed windows or buildings for which the window status is unknown. Howard-Reed et al (2002) supplement Wallace and Ott (1996) by comparing findings from the California home to a similarly instrumented East Coast home in Reston, VA. They conclude that maximal AER typically occurs during mild weather conditions with low winds and small indoor/ outdoor temperature gradients and not the reverse as is often assumed.…”

Section: Air-exchange Ratementioning

confidence: 99%

A pilot study using scripted ventilation conditions to identify key factors affecting indoor pollutant concentration and air exchange rate in a residence

Johnson¹,

Myers

Kelly

et al. 2004

J Expo Sci Environ Epidemiol

View full text Add to dashboard Cite

A pilot study was conducted using an occupied, single-family test house in Columbus, OH, to determine whether a script-based protocol could be used to obtain data useful in identifying the key factors affecting air-exchange rate (AER) and the relationship between indoor and outdoor concentrations of selected traffic-related air pollutants. The test script called for hourly changes to elements of the test house considered likely to influence air flow and AER, including the position (open or closed) of each window and door and the operation (on/off) of the furnace, air conditioner, and ceiling fans. The script was implemented over a 3-day period (January 30-February 1, 2002) during which technicians collected hourly-average data for AER, indoor, and outdoor air concentrations for six pollutants (benzene, formaldehyde (HCHO), polycyclic aromatic hydrocarbons (PAH), carbon monoxide (CO), nitric oxide (NO), and nitrogen oxides (NO x )), and selected meteorological variables. Consistent with expectations, AER tended to increase with the number of open exterior windows and doors. The 39 AER values measured during the study when all exterior doors and windows were closed varied from 0.36 to 2.29 h À1 with a geometric mean (GM) of 0.77 h À1 and a geometric standard deviation (GSD) of 1.435. The 27 AER values measured when at least one exterior door or window was opened varied from 0.50 to 15.8 h À1 with a GM of 1.98 h À1 and a GSD of 1.902. AER was also affected by temperature and wind speed, most noticeably when exterior windows and doors were closed. Results of a series of stepwise linear regression analyses suggest that (1) outdoor pollutant concentration and (2) indoor pollutant concentration during the preceding hour were the ''variables of choice'' for predicting indoor pollutant concentration in the test house under the conditions of this study. Depending on the pollutant and ventilation conditions, one or more of the following variables produced a small, but significant increase in the explained variance (R 2 -value) of the regression equations: AER, number and location of apertures, wind speed, air-conditioning operation, indoor temperature, outdoor temperature, and relative humidity. The indoor concentrations of CO, PAH, NO, and NO x were highly correlated with the corresponding outdoor concentrations. The indoor benzene concentrations showed only moderate correlation with outdoor benzene levels, possibly due to a weak indoor source. Indoor formaldehyde concentrations always exceeded outdoor levels, and the correlation between indoor and outdoor concentrations was not statistically significant, indicating the presence of a strong indoor source.

show abstract