<p><strong>Everyone is affected by the built environment, with indoor environment quality (IEQ) linked to comfort, productivity, health, and wellbeing. Autistic people are widely reported to have differences in how they process sensory information compared to neurotypical people, regardless of age or IQ. However, there is limited systematic research linking these two areas, and what does exist is primarily focused on children in educational environments. An earlier study for the author’s Master of Building Science thesis looked at the effect of IEQ on autistic adults across the built environment. While electric lighting factors were rated negatively by autistic adults in this key resource, it could not provide specific information about the types of lighting systems, layouts, etc. that caused issues. It was also not possible to attribute issues with electric lighting to specific building types.</strong></p><p>This research is an in-depth exploration of autistic people’s perceptions of indoor electric lighting systems in their everyday built environment, using a mixed methods participatory photo diary research design. Autistic participants (n=13) were asked to take photographs of indoor lighting over the course of two weeks and send them in using an online return form. A subsequent direct follow up questionnaire was used to clarify and expand on the initial data analysis. Data collected were a detailed and descriptive mixture of visual photographs, rating scales and text-based comments.</p><p>Participants were able to self-select what they felt was important to them to submit as photographs. As a result, rich data has been gathered. Participants submitted photographs across a wide range of locations, with a wide range of examples of different lighting systems. In general, there were more negative issues than positive effects that came out of the themes of the data analysis, with over half of the photographs submitted of lighting that participants disliked, a quarter neutral, and a quarter liked.</p><p>Four themes were identified: lighting attributes (including location, lighting system layout, lamp shapes, types and number), technical factors (including flicker, noise, colour, glare, brightness, shadows/patterns, reflections and control), reactions to lighting (physical and emotional) and descriptive language. The use of a participatory photography method was successful also in collecting data in a way that was novel and adapted to be accessible to autistic participants. Limitations of the research include the requirement of digital access, and use of questionnaire-based follow-up. This research was also performed in the context of the COVID-19 pandemic, with data collection occurring in late 2019 and follow-up in early 2020 as lockdowns were beginning in New Zealand.</p><p>This research provides many avenues for future research to create more accessible indoor environments. These include the design of electric lighting for comfort in specific environments such as medical waiting rooms and community spaces, preferences of colour temperature of lighting, the need for a technical understanding of flicker parameters for autistic people particularly around dimmable LEDs, investigation of the positive effects of lighting, understanding of the problems of linear lighting laid out in an array, and how people describe lighting that they like and dislike.</p>