Interior design – and biophilic design in particular – go way beyond aesthetics.
Indeed, the spaces we live and work in have a big influence on our mental and physical wellbeing. Either in a positive or in a negative direction.
In this month’s episode of Biophilic Moodboards, we’re looking at thermal & airflow variability; an invisible yet essential aspect to achieve healthy and comfortable interiors.
The benefits of thermal & airflow variability
In the natural world, air is constantly moving. There are cool breezes, sunny areas and corners shaded by the canopy. And the list could go on.
Indoors it’s a bit different. Air is way more stagnant than outdoors and temperature is often controlled via HVAC systems, which set it to remain stable around a value of choice. But this is not necessarily a good thing.
Actually, studies have proven that natural ventilation and thermal variations improve our mood, concentration, and overall wellbeing. *
The importance of options
The concept of thermal comfort is a very personal one. This means that finding the right temperature for all the occupants of a space is almost impossible. And it gets even more difficult when dealing with offices, restaurants and other communal spaces.
As a response to these concerns, biophilic design highlights the importance of:
Changing air temperature and humidity in interiors, moving air touching the skin and varying surface temperatures.
Ability – for the occupants for a space – to control thermal conditions and adjust them to need.
But how to practically apply all this to interior design?
Windows & window treatments
The first and easiest way to improve natural ventilation and control thermal conditions is… operable windows!
Being able to open a window is extremely powerful in its simplicity. Besides adjusting the temperature and introducing lively (and unexpected) airflows into the space, ventilating indoor spaces is essential to clean the air from indoor air pollutants.
Similarly, window treatments are a precious help to shield interiors from extreme outdoor temperatures. This will improve thermal comfort while helping to save on heating & air conditioning energy and costs.
Even when windows aren’t an option, mechanical ventilation systems should simulate natural variations in airflow, temperature, and humidity.
Outdoor spaces are extremely important in a biophilic design, and for many reasons.
Speaking of thermal variability, outdoor spaces give direct access to fresh air, allowing to get some warmth or freshness – according to the weather conditions.
When designing outdoor spaces, it’s therefore crucial to include some overhead coverage. This will provide both shadow and protection from the elements, stretching the usability of the space.
From a design perspective, it’s also preferable to design outdoor spaces as a continuation of the interior. And indoor-outdoor spaces are the ideal inspiration!
Bringing nature indoors can also help with thermal and humidity regulation.
Plants absorb heat, humidity and moisture. Vertical gardens are particularly effective in these regards, as they cluster many plants in one place.
Another example are fireplaces, that create a warmer corner to enjoy in winter.
The temperature felt when touching a surface is more important than one might think.
The everlasting dilemma between wood and tile flooring is a good example of that. And indeed, the choice between the two will also depend on thermal considerations!
Applying the same idea throughout a design, material variations – hence temperature variations – are key to determine overall thermal comfort.
Last but not least, textiles also play an essential role in thermal control.
Blankets, window treatments, rugs… all contribute to making a space warmer or cooler.
Textiles provide easy adjustment options for people sharing the same space, like using a thick blanket if it’s cold or lowering a shade if sunlight is glaring.
Being easy to swap, textiles also help to transition interiors across seasons and ensure optimal thermal comfort all year round.
The importance of thermal & airflow variability in interiors ties into biophilic design’s sensory approach to interiors.
By caring for how people feel in a space, biophilic interiors are able to improve wellbeing, while reconnecting us with our common roots...nature.
- Heschong L. (1979). Thermal Delight in Architecture. (opened in a new window/tab) Cambridge, MA: MIT Press.
- Tham K.W. & Willem H.C. (2005). Temperature and Ventilation Effects on Performance and Neurobehavioral-Related Symptoms of Tropically Acclimatized Call Center Operators Near Thermal Neutrality. (opened in a new window/tab) ASHRAE Transactions, 687-698.
- Wigö H. (2005). Technique and Human Perception of Intermittent Air Velocity Variation. (opened in a new window/tab) KTH Research School, Centre for Built Environment.
- Hartig T., Evans G.W., Jamner L.D. , Davis D.S. & Gärling T. (2003). Tracking Restoration in Natural and Urban Field Settings. (opened in a new window/tab) Journal of Environmental Psychology, 23, 109–123.
- Hartig T., Mang M. & Evans G. W. (1991). Restorative Effects of Natural Environment Experience. (opened in a new window/tab) Environment and Behavior, 23, 3–26.
- Kaplan R. & Kaplan S. (1989). The Experience of Nature: A Psychological Perspective. (opened in a new window/tab) Cambridge: Cambridge University Press.
- Parkinson T., de Dear R. & Candido C. (2012). Perception of Transient Thermal Environments: Pleasure and Alliesthesia. (opened in a new window/tab) In Proceedings of 7th Windsor Conference, Windsor, UK.
- Zhang H., Arens E., Huizenga C. & Han T. (2010). Thermal Sensation and Comfort Models for Non-Uniform and Transient Environments: Part II: Local Comfort of Individual Body Parts. (opened in a new window/tab) Building and Environment, 45 (2), 389-398.
- Arens E., Zhang H. & Huizenga C. (2006). Partial- and Whole-body Thermal Sensation and Comfort, Part II: Non-uniform Environmental Conditions. (opened in a new window/tab) Journal of Thermal Biology, 31, 60-66.
- Zhang H. (2003). Human Thermal Sensation and Comfort in Transient and Non-Uniform Thermal Environments. (opened in a new window/tab) Ph. D. Thesis, CEDR, University of California at Berkeley.
- de Dear R. & Brager G. (2002). Thermal comfort in naturally ventilated buildings. (opened in a new window/tab) Energy and Buildings, 34, 549-561.