BUILDING FOR WELLBEING
With thermal comfort an essential element of our wellbeing, Dr David Brunt of David
Brunt Consulting, explores how a building’s occupants can benefit from radiant heating
Dr David Brunt speaking at the
recent launch of radiant climate
control product, Radiana
16 BuildingProducts.co.uk • Building for Wellbeing
heat back into space (radiative cooling). The
earth ‘radiates’ the heat into space which is
very cold. In the same way, we are warmed
by the infra-red radiation from the ceiling,
or when it’s cold, we radiate the heat in our
bodies not into space but to the cold surface
of a panel as part of a radiant heating or
With radiant systems, hot or cold water is
circulated through the system’s panels to heat
or cool the occupants of the room.
What is thermal gradient?
A thermal gradient is the temperature
difference from one area to the other.
It is important to minimise any
differences and radiant cooling
is particularly good at this.
Typically, the temperature
gradient we are most
concerned about is the one
from the floor to the ceiling,
or from foot to head.
With traditional cooling
systems, there are often
complaints about this variation in
temperature but radiant cooling
systems have been shown to
provide much smaller thermal
gradients, increasing occupant
How is temperature stability
affected by radiant cooling?
Published studies have shown that
24hr temperature fluctuations
are much lower with a radiant
cooling system compared to an
all-air system and the satisfaction
of people living or working in a
radiant-cooled building is higher.
Therefore, a radiant system
maintains a more stable
When it comes to heating and cooling,
what are the main issues affecting
occupant wellbeing in buildings?
Thermal comfort can be defined as ‘the
condition of mind that expresses satisfaction
with the thermal environment and is
assessed by subjective evaluation.’
Strongly linked to our health, wellbeing
and productivity, thermal comfort is ranked
as one of the highest contributing factors
influencing overall human satisfaction in
buildings and it can have physical health
effects. For example, temperature change can
trigger asthma in adults and is also thought
to play a role in ‘sick building syndrome’.
Research has shown that productivity can
be reduced by 4-6% if the temperature is
too hot or cold and in the USA, 41% of office
workers have expressed dissatisfaction with
their thermal environment.
How can we solve these problems?
In order to overcome these issues, it
is important to control the thermal
• controlling the absolute temperature
• keeping the temperature stable throughout
• minimising the difference in temperature
across an area vertically and horizontally
• controlling the humidity
• removing draughts
How does radiant heating and
Radiant cooling mimics the very effective
way the earth heats and cools. The
earth gets heated up by the sun’s
radiation (radiant heating).
During the night, the earth
cools down by radiating that
“Studies show a