The building energy performance gap: Up close and personal

Measurements of completed projects confirm significant gaps between the predicted and actual energy performance of buildings. This is due to: actual occupant behaviour; weather conditions; workmanship/installation errors; systems’ control settings and modelling issues. Recent developments in automated meter reading (AMR) and monitoring and targeting (M&T) make the performance gap visible to owners/operators. Bridging the gap becomes even more important if the industry intends to ‘occupant/climate change proof’ buildings. This paper reviews energy performance gap literature, the findings of a workshop on the subject, and presents ongoing work in this area. It concludes that the energy performance gap can only be bridged through better definition and joint efforts across all actors involved in the design, construction and operation of buildings/building (sub) systems

Measured indoor temperatures, thermal comfort and overheating risk: Post-occupancy evaluation of low energy houses in the UK

There is growing concern in Western Europe that higher insulation and air tightness of residential buildings leads to increased overheating risk. This paper discusses temperature monitoring from identical houses in the Southwest of the UK that were built to low energy standards (Code for Sustainable Homes Level 5). The temperature data were analysed using both established static overheating criteria (CIBSE Guide A) and an adaptive thermal comfort standard (BSEN15251). The houses can be considered uncomfortably warm during summer and are at risk of overheating. The study suggests that occupant behaviour plays an important role in reducing or increasing internal temperatures

The gap between simulated and measured energy performance: A case study across six identical new-build flats in the UK

Monitoring of completed buildings often identifies significant gaps between the predicted and actual energy use of buildings. This is referred to as the ‘energy performance gap’. To date, most research on the energy performance gap has focussed on non-domestic buildings; this paper presents a case study from the UK domestic sector. Monitoring equipment was installed in six identical flats located in a new-build apartment building. The actual energy used during the first year of occupation is compared with the design stage normative Standard Assessment Procedure calculations as well as seven transient DesignBuilder models produced by a cohort of seven MSc Architecture students. As six identical flats were investigated, the paper provides a unique opportunity to develop an energy use distribution on the monitoring side of the energy performance gap. The work demonstrates that the energy performance gap is evident in the domestic sector

Energy saving behaviours among social housing tenants: Exploring the relationship with dwelling characteristics, monetary concerns, and psychological motivations

Increasing our understanding of the factors that influence energy saving behaviour could help in the development of more effective energy saving interventions. This paper describes the first phase of the EnerGAware project which aims to develop a serious game for social housing tenants in the UK. A survey was conducted to inform the design of the game, which investigated the relationship between psychological factors, context-specific factors (i.e. dwelling characteristics and monetary concerns), and energy saving behaviours. In total, 537 households completed a postal survey, with a response rate of 19.4%. The results showed that experiencing difficulty in keeping the home comfortably warm in winter related to behaviour. In particular, concerns about the affordability of heating seemed to be related to more frequent heating-related energy saving behaviours. Experiencing issues with overheating, damp, mould or condensation – and general concerns about energy bills, did not relate to energy saving behaviours. Overall, the psychological factors measured in the study related more strongly to energy saving behaviours; especially the ability to imagine energy use and strong social norms had a positive relationship with energy saving behaviour. The implications of the findings for the design of the serious game are discussed. Thus, the study uses a combined approach examining psychological and contextual factors to illustrate how important behavioural motivators relevant to a specific group of householders can be included in the design of an intervention

Controlling Flexural Waves in Semi-Infinite Platonic Crystals with Resonator-Type Scatterers

We address the scattering and transmission of a plane flexural wave through a semi-infinite array of point scatterers/resonators, which take a variety of physically interesting forms. The mathematical model accounts for several classes of point defects, including mass-spring resonators attached to the top surface of the flexural plate and their limiting case of concentrated point masses. We also analyse the special case of resonators attached to opposite faces of the plate. The problem is reduced to a functional equation of the Wiener–Hopf type, whose kernel varies with the type of scatterer considered. A novel approach, which stems from the direct connection between the kernel function of the semi-infinite system and the quasi-periodic Green's functions for corresponding infinite systems, is used to identify special frequency regimes. We thereby demonstrate dynamically anisotropic wave effects in semi-infinite platonic crystals, with particular attention paid to designing systems that exhibit dynamic neutrality (perfect transmission) and localisation close to the structured interface

Simple non-mydriatic retinal photography is feasible and demonstrates retinal microvascular dilation in Chronic Obstructive Pulmonary Disease (COPD).

BACKGROUND: Chronic Obstructive Pulmonary Disease (COPD) is associated with an increased risk of myocardial infarction and stroke but it remains unclear how to identify microvascular changes in this population. OBJECTIVES: We hypothesized that simple non-mydriatic retinal photography is feasible and can be used to assess microvascular damage in COPD. METHODS: Novel Vascular Manifestations of COPD was a prospective study comparing smokers with and without COPD, matched for age. Non-mydriatic, retinal fundus photographs were assessed using semi-automated software. RESULTS: Retinal images from 24 COPD and 22 control participants were compared. Cases were of similar age to controls (65.2 vs. 63.1 years, p = 0.38), had significantly lower Forced Expiratory Volume in one second (FEV1) (53.4 vs 100.1% predicted; p < 0.001) and smoked more than controls (41.7 vs. 29.6 pack years; p = 0.04). COPD participants had wider mean arteriolar (155.6 ±15 uM vs. controls [142.2 ± 12 uM]; p = 0.002) and venular diameters (216.8 ±20.7 uM vs. [201.3± 19.1 uM]; p = 0.012). Differences in retinal vessel caliber were independent of confounders, odds ratios (OR) = 1.08 (95% confidence intervals [CI] = 1.02, 1.13; p = 0.007) and OR = 1.05 (CI = 1.01, 1.09; p = 0.011) per uM increase in arteriolar and venular diameter respectively. FEV1 remained significantly associated with retinal vessel dilatation r = -0.39 (p = 0.02). CONCLUSIONS: Non-mydriatic retinal imaging is easily facilitated. We found significant arteriole and venous dilation in COPD compared to age-matched smokers without COPD associated with lung function independent of standard cardiovascular risk factors. Retinal microvascular changes are known to be strongly associated with future vascular events and retinal photography offers potential to identify this risk. TRIAL REGISTRATION: clinicaltrials.gov NCT02060292

The growing price gap between more and less healthy foods: analysis of a novel longitudinal UK dataset.

OBJECTIVES: The UK government has noted the public health importance of food prices and the affordability of a healthy diet. Yet, methods for tracking change over time have not been established. We aimed to investigate the prices of more and less healthy foods over time using existing government data on national food prices and nutrition content. METHODS: We linked economic data for 94 foods and beverages in the UK Consumer Price Index to food and nutrient data from the UK Department of Health's National Diet and Nutrition Survey, producing a novel dataset across the period 2002-2012. Each item was assigned to a food group and also categorised as either "more healthy" or "less healthy" using a nutrient profiling model developed by the Food Standards Agency. We tested statistical significance using a t-test and repeated measures ANOVA. RESULTS: The mean (standard deviation) 2012 price/1000 kcal was £2.50 (0.29) for less healthy items and £7.49 (1.27) for more healthy items. The ANOVA results confirmed that all prices had risen over the period 2002-2012, but more healthy items rose faster than less healthy ones in absolute terms:£0.17 compared to £0.07/1000 kcal per year on average for more and less healthy items, respectively (p<0.001). CONCLUSIONS: Since 2002, more healthy foods and beverages have been consistently more expensive than less healthy ones, with a growing gap between them. This trend is likely to make healthier diets less affordable over time, which may have implications for individual food security and population health, and it may exacerbate social inequalities in health. The novel data linkage employed here could be used as the basis for routine food price monitoring to inform public health policy.The present study was undertaken by the Centre for Diet and Activity Research (CEDAR), a UKCRC Public Health Research Centre of Excellence. The authors gratefully acknowledge the funding from the British Heart Foundation, Cancer Research UK, Economic and Social Research Council, Medical Research Council, the National Institute for Health Research, and the Wellcome Trust, under the auspices of the UK Clinical Research Collaboration. AIC was fully supported by the Gates Cambridge Trust. The funding sources had no role in the design and conduct of the study or in the collection, management, analysis, and interpretation of the data.This is the final published version. It first appeared at http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0109343

Accordance to the Dietary Approaches to Stop Hypertension diet pattern and cardiovascular disease in a British, population-based cohort.

The dietary approaches to stop hypertension (DASH) diet could be an important population-level strategy to reduce cardiovascular disease (CVD) in the UK, but there is little UK-based evidence on this diet pattern in relation to CVD risk. We tested whether dietary accordance with DASH was associated with risk of CVD in a population-based sample of 23,655 UK adults. This prospective analysis of the EPIC-Norfolk cohort study analysed dietary intake (assessed using a validated food frequency questionnaire) to measure accordance with DASH, based on intakes of eight food groups and nutrients, ranking the sample into quintiles. Cox proportional hazards regression models tested for association between DASH accordance and incident stroke, ischemic heart disease (IHD) and total incident CVD (stroke and IHD only), as well as CVD mortality, non-CVD mortality and total mortality. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated adjusting for age, sex, behavioral and clinical risk factors and socioeconomic status. Over an average of 12.4 years follow-up, we ascertained 4129 incident CVD events, of which stroke accounted for 1011. Compared to participants with the least DASH-accordant diets, those with the most DASH-accordant diets had 20% lower risk of incident stroke (HR, 95% CI 0.80, 0.65-0.99) and 13% lower risk of total incident CVD (0.88, 0.79-0.99) but no lower risk of CHD (0.90, 0.79-1.02). CVD-related mortality also showed strong inverse associations with DASH accordance (0.72, 0.60-0.85). This study provides evidence for the cardioprotective effects of DASH diet in a UK context

Operations on windows and external doors in UK primary schools and their effects on indoor environmental quality

This study provides a comprehensive analysis of the predictors influencing operations on windows and external doors as well as their impact on IEQ, comfort and energy. The study was carried out in 31 naturally ventilated classrooms in eight primary schools in the UK during non-heating and heating seasons. The state of the windows and external doors was collected by time-lapse cameras and visual observations. Environmental variables impacting window operations were recorded at 10-min intervals. Correlational tests and predictive regression models were used to identify how windows open area (m2) were affected by environmental predictors. Results show that operative and outdoor temperature during the non-heating season and indoor and outdoor humidity during the heating season were the main predictors of windows open area (m2). The main driver for the operation of external doors was occupancy patterns, however, the period that they stayed open was dependent on temperature. The impact of windows and external doors' open area (m2) on operative temperature decreased after 40 min, however, its impact on CO2 level was only noticeable up to 30 min. Through opening more available windows, operative temperature (34% of the time) and CO2 levels (28% of the time) could be reduced during the non-heating season. Furthermore, energy waste could be avoided 67% of the time during the heating season by reducing the set-point temperature and training school occupants on when to operate windows. This study suggests several avenues to improve the impact of controls’ operation on IEQ, comfort and energy