Henry Willem

Formaldehyde and acetaldehyde exposure mitigation in US residences: in-home measurements of ventilation control and source control.

Measurements were taken in new US residences to assess the extent to which ventilation and source control can mitigate formaldehyde exposure. Increasing ventilation consistently lowered indoor formaldehyde concentrations. However, at a reference air exchange rate of 0.35 h(-1), increasing ventilation was up to 60% less effective than would be predicted if the emission rate were constant. This is consistent with formaldehyde emission rates decreasing as air concentrations increase, as observed in chamber studies. In contrast, measurements suggest acetaldehyde emission was independent of ventilation rate. To evaluate the effectiveness of source control, formaldehyde concentrations were measured in Leadership in Energy and Environmental Design (LEED)-certified/Indoor airPLUS homes constructed with materials certified to have low emission rates of volatile organic compounds (VOC). At a reference air exchange rate of 0.35 h(-1), and adjusting for home age, temperature and relative humidity, formaldehyde concentrations in homes built with low-VOC materials were 42% lower on average than in reference new homes with conventional building materials. Without adjustment, concentrations were 27% lower in the low-VOC homes. The mean and standard deviation of formaldehyde concentration was 33 μg/m(3) and 22 μg/m(3) for low-VOC homes and 45 μg/m(3) and 30 μg/m(3) for conventional.

Ventilation Control of Volatile Organic Compounds in New U.S. Homes: Results of a Controlled Field Study in Nine Residential Units

In order to optimize strategies to remove airborne contaminants in residences, it is necessary to determine how contaminant concentrations respond to changes in the air exchange rate. The impact of air exchange rate on the indoor concentrations of 39 target volatile organic compounds (VOCs) was assessed by measuring air exchange rates and VOC concentrations at three ventilation settings in nine residences. Active sampling methods were used for VOC concentration measurements, and passive perfluorocarbon tracer gas emitters with active sampling were used to determine the overall air exchange rate corresponding to the VOC measurements at each ventilation setting. The concentration levels and emission rates of the target VOCs varied by as much as two orders of magnitude across sites. Aldehyde and terpene compounds were typically the chemical classes with highest concentrations, followed by alkanes, aromatics, and siloxanes. For each home, VOC concentrations tended to decrease as the air exchange rate was increased, however, measurement uncertainty was significant. The indoor concentration was inversely proportional to air exchange rate for most compounds. For a subset of compounds including formaldehyde, however, the indoor concentration exhibited a non-linear dependence on the timescale for air exchange

Surveys of Microwave Ovens in U.S. Homes

LBNL-5947E Surveys of Microwave Ovens in U.S. Homes Alison Williams, Hung-Chia (Dominique) Yang, Bereket Beraki, Louis-Benoit Desroches, Scott J. Young, Chun Chun Ni, Henry Willem, Jeffery B. Greenblatt, and Camilla Dunham Whitehead Lawrence Berkeley National Laboratory, Berkeley, California, USA Sally M. Donovan Consultant, Melbourne, Australia Environmental Energy Technologies Division December 2012 This work was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Building Technology, State, and Community Programs, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.

Survey of Hearth Products in U.S. Homes

Author(s): Siap, D; Willem, H; Price, S; Yang, H; Lekov, A | Abstract: There are over 7 million gas-fired fireplaces currently installed in US households. On an annual basis, these use substantial energy. However, the details of the fireplace energy use and the factors that influence it are currently not well understood. Fireplaces are a type of hearth product, which is a product category that primarily consists of fireplaces, stoves, and gas log sets. For the purpose of this study, the fuels used in hearth products are primarily natural gas, propane, or electricity. They may be vented or unvented. This study reports the results of a web survey of 2,100 respondents in the United States performed in February 2016. The responses were cleaned and weighted using the raking method to form a nationally representative population. The reported data include hearth product characteristics, usage information, and repair and maintenance practices. The hearth product characteristics include the hearth product type, fuel type, ignition system type, features, venting, and installation details. The usage information includes seasonal usage of the main burner and standing pilot (if present), daily usage, and the primary utility (whether decorative or for heating). These raw data are further processed and combined with values from the literature to estimate the annual operating hours and energy use and to assess how these are impacted by the hearth product type, features, age, and the main heating appliance, if present. Based on the survey responses, the estimated average annual hours of usage was 234 for the main burner, and 4,593 for the standing pilot. The results presented provide the most comprehensive data regarding hearth products in the United States published to date. These new data allow for an improved understanding of hearth products’ energy use, which in turn may facilitate the development of more informed analyses, and ultimately more efficient hearth products and reduced energy use. These new data also provide insight into topics not previously studied, such as the effect of hearth product features on energy use.

Field-Monitoring of Whole-Home Dehumidifiers: Initial Results of a Pilot Study

Field-Monitoring of Whole-Home Dehumidifiers: Initial Results of a Pilot Study Henry Willem, Camilla Dunham Whitehead, Chun Chun Ni, Venessa Tavares, Thomas Alan Burke, Moya Melody, and Sarah Price Energy Analysis and Environmental Impacts Department Environmental Energy Technologies Division Lawrence Berkeley National Laboratory Berkeley, CA 94720 November 2013 This work was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Building Technology, State, and Community Programs, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 .