Indoor comfort depends more on your skin than the air temperature

Feeling comfortable indoors is not guesswork. Your skin constantly sends information about heat and cold to the brain, and that signal aligns with how comfortable you report feeling.

A new review brought together 172 studies published since 2000 and found strong links between skin temperature and thermal sensation.

The big picture is simple: the face and hands track comfort well, local cooling helps more than local heating, and comfort varies by age, gender, and climate background.

Reading the body’s thermostat

This work was led by Professor John Kaiser Calautit at the University of Nottingham’s Faculty of Engineering.

The team shows why mean skin temperature (MST) matters, because it summarizes the whole body in a single number that rises and falls with how warm or cool people say they feel.

“Skin temperature tells us a great deal about whether people feel too hot, too cold, or comfortable indoors,” said Calautit.

“By bringing together research from around the world, we’ve shown how this knowledge can help design safer, healthier, and more sustainable spaces.”

The review ties skin temperature to how we set up buildings and devices. Older models did not use body signals like this.

They focused on room air, radiant heat, humidity, clothing, activity, and airflow, which can miss how two people in the same room feel very differently.

Face and hands matter most

The analysis shows the face and hands are prime spots to monitor. These areas are sensitive, easy to measure, and not usually covered by thick clothing.

Cooling targeted areas – such as the back or chest – improves comfort more than heating a small spot. That pattern makes sense because the skin has more cold receptors near the surface and cooling quickly changes blood flow.

The results also suggest practical steps for designers. If you want to help people feel better in summer, focus cooling on larger trunk areas instead of only blowing cold air at the hands and feet.

Comfort is not universal

Comfort is not one-size-fits-all. The review reports that older adults are typically less sensitive to warmth, which raises their risk of overheating during hot spells.

Gender can also shape comfort responses. Many studies find that women report stronger sensations across conditions, though results vary.

Where you grew up matters as well. People from warmer regions often respond differently than those from cooler regions, so a single comfort formula will not work for every building or city.

Skin temperature can predict comfort

Research teams are building personal comfort models that use wearable sensors to read skin temperature and other signals, then predict how you feel.

In tests, these models reached strong accuracy with signals from the wrist and ankle paired with heart rate.

Cameras and computer vision are entering the mix. A study comparing thermal infrared skin temperature, thermal image features, and wearables found that automated systems can estimate comfort with off-the-shelf sensors.

This points to future building controls that quietly keep you comfortable without surveys or knobs – and without storing unnecessary personal data – if designed carefully.

Your face carries useful information too. Another study using facial skin temperature built a thermal comfort evaluation method that classified how people felt with fewer sensors and less intrusion.

Machine learning methods matter for how these systems work.

Classification trees and related approaches have shown that a small number of body locations, like arm, back, and wrist, can predict personal comfort well, according to this paper.

Moving toward tailored comfort

Many buildings still rely on the predicted mean vote, a traditional index developed decades ago.

Across a large global database, its accuracy in predicting how people actually feel was about one in three, which helps explain why offices often feel too warm to some and too cool to others.

Putting skin temperature into feedback loops can change that. Smarter control can reduce energy use, cut health risks for vulnerable groups, and respect privacy by using minimal, local signals rather than constant surveillance.

The review also points to equity. Children, older adults, and people who cannot always voice their needs should not be left out of comfort decisions. Systems that read simple physiological cues can help close that gap.

The authors argue for tailored models. A building in Singapore should not run the same comfort rules as one in Stockholm, and a care home should not mirror a tech office.

“Looking ahead, we see a future where smarter building technologies use this physiological data to automatically deliver comfortable, energy-efficient environments with minimal input from occupants,” said Calautit.

Skin temperature improves daily life

Wearables already measure skin temperature to support sleep, recovery, and stress tracking.

With clear consent and careful data handling, the same signal can guide your home to pre-cool a bedroom before you arrive or warm your workspace when your hands grow cold.

Building managers can use aggregated, anonymized data to adjust supply air or chilled water setpoints. A small nudge in the right direction, informed by skin signals, can save energy without people noticing a change.

Engineers can design quieter, simpler systems when they know which body areas matter most. A chair back that gently cools could matter more than a powerful vent at the feet.

Care settings can benefit as well. Monitoring skin temperature trends helps staff protect residents who might not recognize heat stress as quickly.

The study is published in Energy and Built Environment.

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