Chan, Wing-San

Gauthier, Stephanie

Huebner, Gesche M

Shipworth, David

Witzel, Christoph

English

UCL Discovery

“Seeing red, feeling hot? –The impact of illumination on thermal comfort” Gesche M. HuebnerStephanie Gauthier, Christoph Witzel, Wing-San Chan, David ShipworthICAP14-ABS2706July, 13th, 2014The Hue-Heat-Hypothesis –“You feel what you see”• Light with wavelengths at the red end of spectrum / of a low colour temperature make people feel warmer• Light with wavelengths at the blue end of spectrum / of high colour temperature coolerTITLE STYLESUB STYLEImportance of studying the HHH• 20 hours per day spent indoors - often under artificial illumination• Non-domestic buildings1 (commercial offices, hotels, shops, schools, hospitals, etc): 18% of total CO2emissions– 46% for space heating– 11% for cooling & ventilation• Domestic buildings2:  26% of total CO2 emissions– 60% for space heating1 http://www.carbontrust.com/media/77252/ctc765_building_the_future__today.pdf2 https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/201167/uk_housing_fact_file_2012.pdfTool for energy savings!? The HHH – Previous researchSupport No supportItten (1961): individuals in a blue-green painted room started feeling cold at 15 C, in the red one only at 11.1 – 12.2 C. Mogensen (1926): participants rated shapes as colder when they were covered with red or purple materialClarke (1975): employees felt too hot in a cafeteria with orange walls at about 24 C but not with light-blue painted walls. Greene & Bell (1980): no effect of differentially coloured walls on perceived temperature. Fanger et al. (1977): subjects adjusted ambient temperatures to be 0.4°C higher under extreme blue fluorescent light than in extreme red light.Bennet & Ray (1972): thermal comfort judgements did not differ when participants wore blue, red, or clear googles.Candas and Dufour (2005): 48 subjects preferred a colour temperature of 5000 K tothat of 2700 when spending two hours in “slightly warm environments” (~5 points on a scale from 0 to 100). Pedersen, Johnson, & West (1978): Temperature estimates were not affected by a room being painted and decorated in red-orange-yellow hues versus blue-green hues. … …• Aim: To test the HHH under conditions that allow control of – Light– Temperature– Relative humidity– Air velocity– Clothing level– (Metabolic rate)Our approachExperimental Design• Vary in systematic fashion between conditions (and measure correctly)• Impact factors on thermal comfort (in addition to air temperature)• Keep constant between conditions and subjectsSubjects• N = 32• Recruited via the subject pool of the Psychology department• Mean age = 24.18 years (SD = 4.01)• Instructed to wear one specific level of clothing• Background survey: age, gender, weight, heightProcedure• Participants arrive– Sedentary period– Aim: create similar adaptation to temperature / similar metabolic rate• In climate chamber (60 minutes)– Every 10 minutes fill in thermal comfort survey(=dependent variable)– Temperatures (within-subject)• Cooling cycle:  decrease gradually from 24 to 20 °C  • Warming cycle: increase gradually from 20 to 24 °C– Between-subject independent variable: Colour temperature of 2700 K versus 6500 KAnalysis• Repeated-measures ANOVA– with within-subject factor “survey no”– between-subject factor “lighting” and “gender”– Light x survey_no interaction – Covariates: BMI, average temperature over session• For Q4: logistic regression for repeated measuresHypothesis:Comfort higher under warm light than cold light (at the lower temperatures).  1 2 3 4 5 6 7comfortableslightly uncomforuncomfortvery uncomfortextremely uncomforSurvey number(~24 to 20 °C)Do you find the current thermal condition..? - Cooling cycle  2700K6500K1 2 3 4 5 6 7comfortableslightly uncomforuncomfortvery uncomfortextremely uncomforSurvey number (~ 20 to 24 °C)Do you find the current thermal condition...? - Warming cycle  2700K6500KQ2Light: p = .025Light x survey no: p = .047p = .023    p = .003    p = .065n.s.ResultsQuestion Cooling cycle Warming cycleHow are you feeling in this moment? Main effect of light:Warmer under warm lightInteraction effect:At low temperatures colder under cold light. Do you find the current thermal condition [comfortable – extremely uncomfortable]?n.s. Main effect of lightInteraction effect:At low temperatures, less comfortable under cold lightHow would you prefer to feel?n.s. Main effect of lightWould you accept thermal environment?Main effect of light Interaction effect: At low temperatures less acceptable  under cold lightMain effect of lightDo you find this environment [easy –difficult] to bear? Interaction effect:At low temperatures less bearable under cold lightMain effect of lightLukewarm results• Statistical significance?– Only for certain questions– Not consistent for warming and cooling cycle– Only for specific temperature “corridors”• Bad measurement instrument?– Number of people  who do not show any modulation of comfort or “jump around” – Surveys not designed for dynamic conditionsNew study: Observation• Same procedure as above– Cooling cycle only– N = 32 participants (16 under each light)– No comfort surveys– Participants instructed to bring a long-sleeve T-Shirt and a jumper to session, plus blanket provided• Observation study: Changes in clothing• Hypotheses:– More item of clothing put on under cold light than warm light.– Items of clothing put on earlier under cold light than warm light. Observation: ResultsPeople put significantly more clothing on under cold light than warm light.No significant temporal difference (only trend).Outlook• Evidence for some effect of light on thermal comfort• But: needs more testing– In ‘real world’– Better operationalization of ‘thermal comfort’Thanks!Questions?

Seeing red, feeling hot? – The impact of illumination on thermal comfort

https://discovery.ucl.ac.uk/10159121/1/icap_huebner_etal_2014.pdf

Seeing red, feeling hot? – The impact of illumination on thermal comfort

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