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Sensing and Perceiving
Comfort vs Energy Efficiency - Sensation
vs Perception: Some people believe you can build an
energy efficient building and/or put in an energy
efficient furnace/air conditioner and then declare to
your client, "this will make you comfortable." That's
not how it works. As designers all we can do is try to
estimate what the occupants might be doing and wearing
at any given moment in time and place. Then for them,
create the right combination of eight environmental
factors that when integrated by the sensory systems,
statistically result in a subjective perception of being
comfortable. Full stop.
Physiological comfort doesn't start with
perception it starts with sensation.
Just ask the visually impaired person -
they know! |
Why are we swimming upstream? Promote comfort
and energy efficiency will follow.
Copyright 2015 © Robert Bean, R.E.T.,
P.L.(Eng.), All world rights reserved. Originally for
Better
Buildings: Better Business
In 2004, I started www.healthyheating.com with a whopping start
up budget of $5,000 to experiment with the internet as an
educational tool. The purpose - to serve as an interpreter
between the health and building sciences with a focus on thermal
comfort, indoor air quality and the energy required to condition
people and spaces. The key strategy - enable discerning
consumers and building owners to make better decisions regarding
their choice in architecture, interior design and HVAC systems
without having to become academics. With an annual operating
budget of another “bank breaking” $1,000/year we have maintained
a steady course in disseminating the work of scientists from all
over the world. So what are the two key principles we have
concluded to date?
1. Design for people and good buildings will follow.
2. For resilience and sustainability, improvements in 1st law
energy efficiency should not be done in isolation without
increasing 2nd law exergy efficiency.
Now I only have space in this piece to address item #1 so let’s
begin by stating the obvious. Since 2004 it is likely hundreds
of millions of dollars have been spent in North America
promoting energy efficiency rather than focusing on the five
senses that humans use to judge the built environment. So hold
that thought and consider this…the highly acclaimed Rocky
Mountain Institute (RMI) recently provided, “70% of whole home
performance customers cited comfort as a reason for their
upgrade”. Stay with me on this. Comfort is a broad topic but as
it pertains to the thermal part, as an example; only three
percent (3%) of industry can define it, only one and one half
(1.5%) own the thermal comfort Standards and less than one
percent (1.0%) can list the ten key metrics. How do I know? I’ve
asked. In fact I’ve been asking audiences since 2004. If you
want witnesses just ask the thousands of people who have sat in
my classes.
Consumers are telling industry they want comfort and we keep
responding with energy efficiency as if the two were synonymous.
Now I’m not a Ph.D., just a lowly technologist just trying to
scratch out a living but even I can figure out that if millions
of people are looking for comfort from an industry purported to
be in the comfort business, better than 3% ought to be able to
define it, own the Standards and be able to describe the
metrics.
So what are the consequences of investing heavily in the
promotion of energy efficiency rather than comfort? Let me
explain. When asked how to design a comfortable home, energy
focused professionals will say design with simple geometries,
orient the home and select aspect ratios for energy
conservation, tighten up the enclosure, increase the levels of
insulation, reduce the window to wall ratios and improve
fenestration performance. Whilst all of this is true, and this
will come as a shock to most, none (that would be zero) are
prerequisites found within thermal comfort standards such as
globally recognized and universally referenced ASHRAE Standard
55 or ISO 7730. Likewise when asked what instruments do energy
professionals use to asses a home for comfort, the default
answer is blower doors and thermographic cameras and yet neither
of these devices are used in thermal comfort assessments. Energy
efficiency and comfort are not the same, different standards –
different instruments.
So I’m going to share with you three key point that students
from my
Integrated Design course would like industry to know:
1. Where an energy efficiency approach says adding insulation
reduces energy consumption, the indoor climate approach says
adding insulation results in higher mean radiant temperatures (MRT’S)
in winter and lower MRT’s in summer. No occupant ever
interviewed ever said they wanted to live in a meat locker or
oven and if preventing that with insulation conserves energy all
the better. The broader populace gets comfort – they generally
don’t get u values, conduction, kilowatts and therms and thermal
bridging even though the results are the same from an energy
perspective.
2. With regards to leakage, the energy efficiency approach says
lower your operating costs by tightening up the building to
prevent heated or cooled air from leaving and hot and cold air
from entering. Whilst this is true, the comfort approach says
houses that leak enable undesirable drafts, sounds, odours (odors)
and untreated air into the home contributing to poor thermal
quality, bad acoustics and low air quality. Again, the broader
populace gets the benefits of a quiet, thermal comfortably home
with air of good quality, they don’t generally understand
Pascals, stack effect and infiltration. The results are the same
from an energy perspective but only comfort speaks to consumers
in everyday language.
3. When it comes to windows, energy efficiency says conserve
cooling and heating energy by reducing window to wall ratios and
upgrading from double pane to triple pane glass with low
emissivity films and argon fills. Whilst true, the comfort
approach says improving window performance prevents windows from
behaving like radiators in summer and freezers in winter,
mitigates glare and solar radiation which breaks down interior
finishes contributing to poor air quality and destruction of
property. Once again, home owners get glare, preservation of
finishes and thermal discomfort – they don’t get emissivity,
solar heat gain coefficients or visible transmittance.
Now if you made it this far you likely “get it” or are arguing
that this is semantics. But it isn’t. Only the comfort approach
starts with the occupants senses in mind and in case you have
forgotten, comfort is the DNA for designing and constructing
buildings not energy efficiency. So here’s the thing…when you
focus on comfort the light comes on in an eureka moment and
people get twitter crazy. In fact you can see the power of
focusing on comfort in the messaging from Delos and the Well
Being Standard® and you can see it in statics from RMI and from
the Center for the Built Environment. Global Institutes such as
Harvard University, the Danish Technical University, and Seoul
National University and many others are advocating the benefits
of comfort on wellness, learning, productivity and health. These
items resonate with the general public.
This logic of putting human needs at the center of the design
process is the ethos of world famous IDEO and can be applied to
benefit most every aspect of energy efficiency in building
design. It has been my experience over the past three decades
that there are less people who start from a position of energy
efficiency and more who start from a position of avoiding indoor
environmental discomforts. Why are we swimming upstream when we
could go with the flow? Promote comfort and energy efficiency
will follow.
I’m going to be talking more about this at the
Better
Buildings: Better Business Conference; and will be addressing
the energy and exergy efficiency aspects during our workshop
with industry colleague John Siegenthaler, P.E, hope to see you
there! |
