Application of a transient hygrothermal population model for house dust mites in beds: assessment of control strategies in UK buildings

Farren²,

Howieson

et al. 2015

IJERPH

The need to reduce carbon emissions and fuel poverty has led to increased building envelope air tightness, intended to reduce uncontrolled ventilation heat losses. Ventilation strategies in dwellings still allow the use of trickle ventilators in window frames for background ventilation. The extent to which this results in “healthy” Indoor Air Quality (IAQ) in recently constructed dwellings was a concern of regulators in Scotland. This paper describes research to explore this. First a review of literature was conducted, then data on occupant interactions with ventilation provisions (windows, doors, trickle vents) gathered through an interview-based survey of 200 recently constructed dwellings, and measurements made on a sample of 40 of these. The main measured parameter discussed here is CO2 concentration. It was concluded after the literature review that 1000 ppm absolute was a reasonable threshold to use for “adequate” ventilation. The occupant survey found that there was very little occupant interaction with the trickle ventilators e.g., in bedrooms 63% were always closed, 28% always open, and in only 9% of cases occupants intervened to make occasional adjustments. In the measured dwellings average bedroom CO2 levels of 1520 ppm during occupied (night time) hours were observed. Where windows were open the average bedroom CO2 levels were 972 ppm. With windows closed, the combination of “trickle ventilators open plus doors open” gave an average of 1021 ppm. “Trickle ventilators open” gave an average of 1571 ppm. All other combinations gave averages of 1550 to 2000 ppm. Ventilation rates and air change rates were estimated from measured CO2 levels, for all dwellings calculated ventilation rate was less than 8 L/s/p, in 42% of cases calculated air change rate was less than 0.5 ach. It was concluded that trickle ventilation as installed and used is ineffective in meeting desired ventilation rates, evidenced by high CO2 levels reported across the sampled dwellings. Potential implications of the results are discussed.

Section: Discussionmentioning

confidence: 99%

Occupant Interactions and Effectiveness of Natural Ventilation Strategies in Contemporary New Housing in Scotland, UK

Farren²,

Howieson

et al. 2015

IJERPH

“…In some instances, heat reduction through ventilation is a low-cost activity (for example, summer ventilation of solar gain, or night-time ventilation under 'free-running' mode (Ucci et al, 2011), however during the heating season, venting of incidental gains from energy sources (space and water heating, electrical items) will likely incur an energy penalty.…”

Section: Discussionmentioning

confidence: 99%

Meta-analysis of indoor temperatures in new-build housing

McGill

Building Research & Information

Robertson

et al. 2016

Despite growing concerns about overheating, there is a lack of evidence regarding the scale of the problem, particularly in contemporary UK housing. This paper presents the results of a meta-analysis of indoor temperatures in selected low-energy housing.Temperature data recorded at 5 minute intervals in 60 dwellings across 19 demonstration projects (2012)(2013)(2014) were collated and analysed to investigate the prevalence of overheating.Findings evidence high summertime temperatures, with 27% of living rooms exceeding 28°C during August. Based on the CIBSE threshold of 5% annual occupied hours >25°C, 57% of bedrooms and 75% of living rooms were classified as having overheated. Overall, 30% of living rooms exceeded the adaptive comfort threshold of >3% occupied hours The Zero Carbon Hub is a non-profit organisation established in 2008, to take day-to-day responsibility for the achievement of the UK government's target of zero carbon homes from 2016.The hub recently undertook a comprehensive study reviewing a considerable body of knowledge relating to overheating in UK dwellings (Zero Carbon Hub, 2015a;2015b;2015c;2015d;2015e;2015f;2015g;2015h). They stress that one of the most significant challenges of addressing overheating has been the lack of evidence regarding the scale of the problem in a domestic context The aim of this paper is to identify the prevalence of overheating in new-build energy efficient dwellings through a meta-analysis of the existing temperature data gathered as part of the Innovate UK (formerly Technology Strategy Board) BPE programme. This will be achieved by; i) Identifying the prevalence of overheating using static (Passivhaus and CIBSE) criteria and the adaptive method, ii)Exploring the relationship between overheating prevalence and building characteristics (including construction, dwelling type and region), iii) Examining seasonal temperature variations, and iv)Comparing indoor temperatures in homes with and without MVHR systems.

“…This approach fits with that of tackling the bedroom in order to improve the environment in a bed. 24,92 It also aligns with a DEFRA briefing that includes ‘an airing cupboard served by MVHR’. 93…”

Section: Discussion: Towards Healthy Energy-efficient Dryingmentioning

confidence: 91%

“…This approach fits with that of tackling the bedroom in order to improve the environment in a bed. 24,92 It also aligns with a DEFRA briefing that includes 'an airing cupboard served by MVHR'. 93 However, the EADL simulations indicate that heating loads for dedicated drying cupboards remain significant.…”

Section: Regulation and Best Practicementioning

confidence: 88%

Domestic laundering: Environmental audit in Glasgow with emphasis on passive indoor drying and air quality

Porteous

Indoor and Built Environment

Menon

et al. 2013

As the UK and Scottish governments aim for zero-carbon housing, with tightly sealed building envelopes becoming paramount, indoor air quality (IAQ) and its implications for health has become a concern. This context relates to the reported findings of a 2008-2011 study, 'Environmental Assessment of Domestic Laundering', concerning the prevalence of passive indoor drying (PID). Assessment of PID impacts, shaped by built and social context including occupants' habits and trends, draws on monitored data from 22 case studies out of a wider survey of 100 dwellings in Glasgow. The smaller group included analysis of air samples, and provided scenarios for enhanced dynamic modelling via laboratory work on moisture buffering.The evidence suggests PID has important implications for energy consumption and IAQ; in the latter case because moisture levels are likely to boost dust mite populations and concentrations of airborne mould spores. Thus findings suggest possible negative impacts on health. Further work concerning VOCs and laundering is also advocated. The paper concludes by recommending amended building standards allied to design guidance for improved practice; these aiming to prevent PID moisture diffusion within habitable rooms by upgrading minimum requirements, and also to require enhanced outdoor drying facilities.