Science advances within disciplines. Plant
physiologists study transpiration rates
and stomatal conductance. Materials
engineers study thermal mass, specific
heat capacity, and thermal conductivity.
HVAC engineers follow ASHRAE Standard 55
(2023), which defines six thermal comfort
factors: metabolic rate, clothing
insulation, air temperature, radiant
temperature, air speed, and humidity.
[7]IAQ researchers track formaldehyde,
benzene, and toluene concentrations,
governed by WHO guidelines (2010) setting
exposure limits.
[4]Each discipline publishes in its own
journals, attends its own conferences, and
speaks its own vocabulary. This is the
blindspot.
NASA's Clean Air Study (Wolverton,
Johnson, and Bounds, 1989) demonstrated
that interior landscape plants removed
benzene, formaldehyde, and
trichloroethylene from sealed plexiglass
chambers, achieving up to 90 percent
reduction in 24 hours.
[4] The study was
groundbreaking, but it was designed for
space stations: sealed environments with
no natural ventilation.
Cummings and Waring (2020) systematically
reviewed 196 experiments from 12 published
studies in the Journal of Exposure Science
and Environmental Epidemiology. Their
conclusion: potted plants do not improve
indoor air quality at practical densities.
Natural building ventilation already
removes VOCs at rates that would require
10 to 1,000 plants per square metre to
match.
[5] The NASA findings, real in
sealed chambers, do not transfer to
ventilated offices. Plant science studied
air purification. Building science studied
ventilation. Neither designed a system
combining both.
ASHRAE Standard 55 addresses thermal
comfort through air temperature, radiant
temperature, and air speed. Its adaptive
model, adopted since 2004, recognises that
occupants interact with their environment,
adapting behaviourally and
physiologically.
[7] But the standard was
written for mechanical systems. Plants are
absent from the framework. No ASHRAE
committee has evaluated managed plant
clusters as personal comfort devices.
He, Yu, Ozaki, Dong, and Zheng (2020)
reviewed bio-inspired cooling technologies
for buildings in Energy and Buildings.
They documented heat transfer mechanisms
used by animals and plants, noting the
potential for creating harmony between
buildings and nature while enhancing
indoor environmental quality and energy
efficiency. Yet their review found these
mechanisms remain academic.
[16]A 2024 systematic review in Intelligent
Buildings International examined 74
peer-reviewed papers on biophilic design
in workplaces. The findings: significant
psychological, physiological, and
cognitive benefits with varying effect
sizes.
[14] Plants improve wellbeing. But
no study in the review integrated thermal
cooling, humidity correction, air quality
improvement, and cognitive benefit into a
single deployable system.
Four disciplines. Four evidence bases. One
blindspot. Biothermal Microconditioning
occupies the intersection: managed indoor
plant clusters that cool the person
(comfort engineering), buffer heat through
substrate (materials science), transpire
humidity into dry air (plant science), and
filter airborne compounds at the breathing
zone (IAQ). The category was hidden
because no discipline had reason to look
across all four. Easy Retrofit. 1 day.
