At a time when the UK government has its sights on zero-carbon housing, in part achieved by tightly sealed envelopes and mechanical heat recovery ventilation (MHRV), the issue of indoor air quality (IAQ) and its implications for health has moved up the agenda; this in parallel with anxiety about the rising energy consumed by appliances, which is offsetting savings on space heating, water heating and lighting. In this context, this paper reports particular findings of a 2008-2011 EPSRC-funded research project: Environmental Assessment of Domestic Laundering, which relate to passive indoor drying (PID). To assess PID impacts, the study draws on monitored data from 22 case studies out of a wider survey of 100 dwellings in Glasgow, including laboratory analysis of air samples, and enhanced parametric dynamic moisture modelling. The evidence indicates that PID is a serious concern in terms of IAQ – firstly, apparent association of PID with high concentrations of mould spores, taking due account of confounding variables; secondly, moisture levels likely to boost dust mite populations; thirdly, potentially harmful chemicals in fabric conditioners, in particular PID linked to the concentration of acetaldehyde, a water-soluble volatile organic compound (VOC). The implication of PID for increased energy consumption is also addressed briefly, a broad-brush comparison being made with tumble-drying in this regard. A further moisture addition associated with domestic laundering is steam ironing, which, like PID, occurs in a context of other moisture sources and typically poor ventilation regimes (air too moist and CO2 too high). The paper concludes with outline recommendations for reformative building standards and design guidance, the aim to prevent PID moisture diffusion within habitable rooms by linking ‘quarantined’ drying spaces to dependable ventilation supply and exhaust systems

Previous narrative:

This paper is the result of a 3 year ESPRC funded project (£520759, EP/G00028X/1) undertaken in collaboration with Energy System Research Unit, University of Strathclyde, and Centre for Research into Indoor Climate and Health, Glasgow Caledonian.

The overall research aim of the study – ‘Environmental Assessment of Domestic Laundering’ (EADL) – was to investigate the energy (how significant a proportion of consumption) and other potentially detrimental environmental impacts attributable to domestic laundering and develop recommendations to address and improve both aspects. This paper concentrates on the aspects of the first of the project modules listed below that relate passive indoor drying (PID), and to a lesser extent ironing, to both air quality (IAQ) and energy efficiency (EE).
The summarised tripartite research objectives of EADL, informing targeted dissemination, were:
1) Project Module (PM) 1: To evaluate all significant environmental impacts of domestic laundering in varied house types with a view to identifying: a) overall energy use and CO2 emissions resulting from the means used; b) particularly for drying, the balance between energy efficiency and good air quality; c) adverse indoor environmental problems such as condensation risk and associated health impacts; this to be facilitated by means of a two-stage survey of representative dwellings, using an ‘interview-observe-measure’ methodology to devise key scenarios for controlled laboratory experiments and simulation studies (PM 2 and PM 3).
2) Project Module (PM) 2: To measure and improve knowledge of transient, moisture-related properties of relevant materials, surface finishes, furniture, etc. associated with social housing (low-income groups relate to prevalence of certain type of furnishings) and to carry out laboratory experiments based on PM 1 scenarios – to provide high quality data for ESP-r model validation.
3) Project Module (PM) 3: To generate a theoretical framework enhancing the capabilities of ESP-r to dynamically model transient moisture transport; to develop a procedure for undertaking parametric tests to cover the large number of factors that influence health and comfort risks; and to extract the important
performance metrics for the design variables studied, based on scenarios devised in PM 1 and material tests in PM2. This will include heating and ventilating regimes relative to passive indoor drying methods in differently planned and constructed house types.

The projects has been widely published through a series of research outputs (Design Guide: Healthy Low Energy Home Laundering. MEARU, Glasgow. ISBN 978-0-9571595-0-1; Sensing a historic low-co2 future. In: Chemistry, Emission Control, Radioactive Pollution and Indoor Air Quality. InTech, pp. 213-246. ISBN 978-953-307-570-9; Communal Residential Laundry Washing And Drying 13 Can It Provide Demand-Side Electrical Load Flexibility? In: Microgen’II: Second International Conference of Microgeneration and Related Technologies, 4 to 6 April 2011, University of Strathclyde, Glasgow, Scotland; isplacing Electrical Energy for Drying Domestic Laundry by Practical Solar Upgrades - Proposed Glasgow Housing Case Studies. In: EuroSun 2010, Graz, Austria, Septemerb 21st- 1st October 2010, Graz, Austria; Economic and Environmental Impact of Communal Laundry Spaces in High Density Housing in the UK. The International Journal of Environmental, Cultural, Economic and Social Sutainability, 6 (2). pp. 191-202. ISSN 978-1-86335-766-1; The economic and environmental impact of communal laundry spaces in high density housing in the UK. In: The International Journal of Environmental, Cultural, Economic and Social Sustainability (Volume 6, Number 2). Common Ground Publishing LLC, Champaign, Illinois, USA, pp. 191-202. ISBN 978-1-86335-766-1) and dissemination including widespread coverage in the press both UK and internationally (including pieces on the BBC News, BBC World TV, Daily Telegraph, Independent, Daily Mail, Daily Express, Daily Mirror, Huffington Post, European Daily and over 100 International news publications) and dissemination through industry events such as Ecobuild, and events for SFHA and institute for Housing.