Thermal comfort is hard to define; it isn't measured by temperature but is understood by an individual's perception of whether they are too hot or cold. When designing a comfortable and effective space, this subjectivity must be taken into consideration to achieve optimum thermal comfort levels for inhabitants.
Thermal comfort can be judged by two main factors: environmental and personal.
Environmental factors include:
· Air temperature
· Radiant temperature
· Air velocity
Personal factors focus on:
· Clothing insulation
· Metabolic heat
· Psychological factors
The purpose of a space can influence the temperature and therefore our perceptions of what is an appropriate temperature is often already predetermined. For example, a foundry is meant to be hot and a supermarket is designed to be cold, so we take steps to accommodate this by removing or adding extra layers of clothing when we enter these spaces.
The subjectivity of individual thermal comfort levels can create challenges in the workplace where a variety of perceptions, needs, and environments are at play. If the thermal comfort level of a workplace is not attuned to the staff’s comfort levels, and the types of tasks being undertaken, this may affect the health, morale, and productivity of employees. The UK has an Approved Code of Practice for workplace temperature which should normally be at least 16°C but if the work involves rigorous physical effort, it should be at least 13°C.
Biology has an impact on thermal responses. Women suffer from disordered thermal comfort during their menopause, however, personal factors may play a role in the difference in thermal comfort levels between sexes. During warm weather, for example, women tend to wear less, or lighter clothing than men, which might play a part in a heightened thermal awareness.
Schools are another environment that needs to be carefully thermally attuned so as to foster learning and productivity, otherwise, children’s health and learning may be negatively affected. Children are more sensitive to heat than adults as they have a higher core body temperature and less developed thermoregulation capabilities meaning they prefer and require a lower ambient temperature.
Thoughtful school design can significantly increase a child’s educational performance but unfortunately, many schools have not been designed to encourage passive heating and cooling, or fitted with effective heating and cooling systems, be that due to poor design choices, old buildings being used as schools, overcrowding and funding cuts across public services.
Many classrooms across the UK are installed in temporary portable cabins, which can become stifling during the summer months due to poor ventilation and being constructed from inadequate materials that absorb and retains solar energy. Higher temperatures, poor air circulation, and higher humidity in classrooms can also lead to health problems, inclusive of respiratory complaints, dehydration, and sick building syndrome.
In a survey conducted by the World Green Building Council for Better Places for People, entitled Thermal Comfort in Schools, they identified how much thermal comfort impacts on children’s learning and productivity.
A study of 75,000 New York City students revealed that for every 1 degrees increase in temperate, students suffered a 0.2% decrease in test scores, and in a study of more than 3,000 US students, it was established that for each 1 degrees decrease in classroom temperature, a 12-13 point increase in math scores was achieved, whilst a survey of over 4000 Finnish students revealed that those who felt their classroom’s thermal levels were ‘comfortable’ achieved 4 percent more correct answers in a maths test than those who were hot.
A best in class example of a thermally efficient school design is Bartholomew Barn, a new addition to King Hawford’s School in Worcester. Designed to Passivehaus standards by Associated Architects and manufacturers Saint-Gobain, the project is the first Multi Comfort building in the UK and brings together the latest innovations in passive design, building materials and construction techniques to deliver a low energy building that is attuned to provide full sensory comfort and increase wellbeing.
Every winter, there is a spike in deaths, particularly amongst the elderly, due to cold weather and surge heating prices. According to data collected by the National Office of Statistics (England and Wales), from 2016- 2017 there were a reported 34,300 excess winter deaths (EWD), representing an excess winter mortality index of 20.9% -- the second highest of the last five winters.
The most commonly affected are women and the elderly. While particular volatile strains of influenza has been cited as a leading reason for these statistics, respiratory disease is also common, which is exacerbated by cold weather and damp interiors, and those who are affected are often of low income, which suggests that an inability to heat the home due to financial reasons could be a factor in such a high mortality rate. Older individuals are more vulnerable to the effects of cold weather due to biological reasons. Their skin and blood are thinner, immune systems weaker, and restricted mobility means that their lifestyle is more sedentary than those of a younger age, meaning they are more prone to feeling the cold.