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Being responsible for a significant proportion of total heat loss in façade dominated buildings, the design and specification of the envelope, particularly the building's glazing system, is a key factor in determining overall energy consumption.To address this, an innovative double glazed façade system comprising parallel transparent / translucent plastic slats sandwiched between the glass panes to form a Parallel Slat Transparent Insulation Material (PS-TIM) system is proposed as a potential solution. This PS-TIM system reduces heat transfer between the glazing panes whilst maintaining access to solar radiation and daylight.The presence of the PS-TIM structure significantly affects the thermal and optical performance of the window system in which it is employed. This presents a further significant challenge when trying to predict its performance using dynamic building simulation approaches. Using a typical small office as a case study subject to varying climatic conditions, we investigate the thermal and optical behaviour of a range of PS-TIMs with respect to their daylight and energy performance. We find that when 2 compared to a conventional double glazed system, the application of PS-TIMs can result in a more visually comfortable and uniformly lit environment, which might be desired in an office space, and, in the specific case of the small office under test, can result in a reduction in energy consumption of up to 35.8%. Furthermore, having explored the performance of the system in response to varying climatic conditions, we also present some advice as to how architects and engineers might apply PS-TIMs to window systems or glazed façades.

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Thermochromic (TC) windows have the ability to regulate daylight and control the solar heat gains that shape a building's internal environment. They therfore offer the potential to improve indoor comfort and reduce building energy demand when used in place of traditional clear glazing systems. However, the quality of the luminous environment is affected due to their chromatic appearance (e.g. common TC coatings impart a bronze or blue hue), resulting in changes to correlated colour temperatures (CCT). Previous studies show that experiments performed under daylight conditions are difficult to be control, while those conducted under artificial lighting conditions cannot faithfully reproduce window properties. In order to investigate the influence of TC windows on visual performance and comfort of subjects in an efficient and economical way, an innovative test room cubicle was designed. It is a mock-up office lit by an artificial window, simulating luminous conditions filtered through two types of TC window (one blue tinted and one bronze tinted). Clear glazing was used as a reference.Objective visual tasks involving Landolt charts and subjective assessments made using questionnaires were used to determine subjects' response to the three different luminous conditions. Results show that the experimental method is effective at determining human response to chromatic glazing. Additionally, the method is flexible due to its small scale and its ability to artificially represent different window types.

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