Consumers are upgrading HVAC systems to higher
efficiency equipment and controls without understanding that often such
equipment when operated the old way, does not provide energy
For example, a 98% efficient boiler only achieves
such high performance when it operates at low temperatures
typically below 80 deg F (27 deg C).
Regardless of the use of programmable
thermostats, when a 98% efficient boiler is run at 180 deg F
(82 deg C) it still only achieves a nominal 85%.
Likewise if people are relying on programmable
thermostats for savings it’s important to know that a thermostat
only tells the boiler that it "could" run but not at what
temperature it "should" run at. This is not a trivial matter.
If you are upgrading to reduce your energy
consumption, you have to
look at the entire system – it’s not enough
just to replace the equipment.
99% of all retail type thermostats only measure
the air temperature - consider that in light of these two
statements made 150 years apart...
"the Commissioners of the General Board of Health
advocated as one of the requirements for comfort that the walls
of a room be at least as high in temperature as the general
temperature of the room, while they included cold walls or
floors amongst the conditions which make for discomfort.”
National Building Code of Canada v2010: Section A-220.127.116.11.(1)
Use of Thermal Insulation or Mechanical Systems for
Environmental Control states, “In addition to controlling
condensation, interior surface temperatures must be warm enough
to avoid occupant discomfort due to excessive heat loss by
Thermostats are supposed to be your ambassador to
your HVAC system but they do a miserable job because they
don't sense what we sense.
...and this from the UK's Health and Safety
most commonly used indicator of thermal comfort is air
temperature – it is easy to use and most people can relate to
it. But although it is an important indicator to take into
account, air temperature alone is neither a valid nor an
accurate indicator of thermal comfort or thermal stress.”
Still the worlds most perfect thermostat
The thermostatic radiator valve was invented over
70 years ago and its simplistic design is just as reliable today
as it was back in the day.
A few features:
*It has no power
*Batteries not required
*Was the first wireless stat
*Is fully modulating
*Senses operative temp.
*One (1) page IOM manual
*Works like a door knob
*Turn right for less heat
*Turn left for more heat
*Anyone can work it
*Perfect for reduced:
- manual dexterity
- visual acuity
- cognitive abilities
Perfect for grumpy designers and their clients who are sick and
tired of technology stealing away valuable fishing time!
"The importance of individual temperature control
in offices was established in the 1980s and 1990s.
Unfortunately, the advantages of individual temperature control
have not been realized well in practice, largely because of
problems in the usability of thermostats."
Sami Karjalainena, VTT Technical Research Centre of Finland
Here's the result of consumers not satisfied with
"energy saving" claims from the NEST Learning Thermostat...
Plaintiff Justin Darisse ("Plaintiff') brings
this action on behalf of himself and all others similarly
situated against Nest Labs, Inc. Plaintiff makes the following
allegations based upon information and belief, except as to the
allegations specifically pertaining to himself, which are on
NATURE OF THE ACTION
1. This a class action against Defendant Nest Labs, Inc.
("Defendant") for using false misleading advertising, in
website, print, and point-of sale promotional materials, as well
as product packaging, to promote and sell the Nest Learning
2. Nest is a wireless thermostat that can be remotely controlled
from smartphones and tablets. In 2011, Defendant launched Nest,
a sleek "new generation" thermostat that was supposed
revolutionize thermostats, not unlike the iPod revolutionized
music playing devices.1 But Defendant released a fancy,
overpriced gadget (pictured below), which, while aesthetically
"cool" like the iPod, fails at even the most basic function of a
thermostat: accurately gauging and controlling temperature.
3. Defendant promises that Nest will provide energy and cost
savings that Nest does provide. In fact, Nest increases energy
use and costs because, contrary to Defendant's representation
that Nest uses "multiple temperature sensors to determine the
ambient temperature with a high degree of accuracy," customer
reports and Defendant's own admissions show that Nest is so
defective that it cannot correctly gauge ambient temperature.
4. Nest's base and faceplate heat up, which causes Nest's
temperature reading to be from two to ten degrees higher than
the actual ambient temperature in the surrounding room. This
defect prevents the thermostat from working properly. As a
result, Nest users do not experience the advertised energy
Thermostats - Part I
Copyright (c) 2012,
Robert Bean, R.E.T., P.L.(Eng.),
and content contributors
"Only one out of four consumers program their
set back thermostats"
source: Energy Information
Administration; 1978, 1987, & 1997 Residential Energy
Consumption Surveys, Ref. Decision Analysts, American
Comfort Survey, 2000
"It has been a constant observation during
our research that all common temperature controllers to date
are quite impossible to use and understand correctly."
source: R. Vastamaki, I. Sinkkonen,
and C. Leinonen, “A behavioural model of temperature
controller usage and energy saving,” Personal and Ubiquitous
Computing, vol. 9, no. 4, pp. 250–259, 2005
"...thermostat usage was found to be
weather dependent based on behavioral data from
participants" source: Bernardoni, S.,
Curtis, M., Koliner, J., (2015). Engaging with a
Thermostat: Using Seasonal and Connectivity-Based
Differences in Residential Thermostat Use to Maximize
Savings. WECC, Madison, Wisconsin
Suffice to say there is no shortage of debates about setback
thermostats. We remain neutral since valid research supports their use
in some applications. Our main issue with most thermostats
research shows users manually operating
the devices regardless of their technological features.
Anyways, rather than perpetuate the debate amongst the real research and
plethora of anecdotal energy savings claims, we thought we
would present a different side that says, “just
because a control could potentially reduce energy use,
doesn't mean that it is operated in such a way that energy
reductions are achieved.”
Figure 1. A collage of
programmable thermostats - it doesn't help users to have so
many choice with so many options, it just creates "paralysis
through analysis" - also most of them fail to completely
sense what occupants sense.
The following is a list of scientific papers
many which have studied how people actually use these
devices with success and shockingly how they often end up using more
energy than what they were intended to save.
Why? Because many people find them too complicated to operate so
they are operated incorrectly.
and Sensory Resources A note on broken link:
as much as we try to maintain links to third party sites, in the event of a
broken link it will be necessary to search for the title using your browser.
case you haven't seen it all...Direct Energy presents "Energy Zombies:
Thermostat Wars". This is one way to make light of the discomfort in peoples
homes...evidently it's a big enough deal that it was worthy of a video from a
distributor of energy services with over 6,000,000 customers.
me it reaffirms just how barbaric some consumers must become as a result of the
building industry ignoring the fundamentals of IEQ and standing upon
to code buildings and
programmable thermostats as an acceptable benchmark in construction and
Sweaters, cuddling and everyone agreeing on a single temperature from a single
thermostat that doesn't represent what everyone is feeling...what marketing
person from utopia wrote this video?
We love this...so representative of families
across the continent...what does it say about thermal comfort and control
The use of "dummy" stats is universal which we
would argue has ethical implications...we would love to hear your thoughts in
our discussion group.
The Big Bang Theory - Sheldon & Leonard argument
over the thermostat. A classic and to think the thermostat was part of the
These women sharing their fights
over the thermostat...wait for the part where a husband deliberately locked out
the adjustment features...
If you Google search, "Thermostat Wars + youtube" you'll get about 11,500
results. If you Google search the phrase "Thermostat Wars" you get about 506,000
One would think that such a prolific problem would tell industry and consumers
that thermostats make a poor proxy for comfort no matter how sophisticated the
device. It should also tell you much society has been programmed to think that
72F (22C) air temperature is the exclusive proxy for comfort when it is only one
of ten (1 of 10) metrics that must be considered when designing spaces. It
should also tell you how the architectural industry has disconnected comfort
from building performance when in fact they are intimately connected.
As we have noted for over 15 years, less than 3%
of industry is aware of what thermal comfort is and of those that do, only 1.5%
actually own ASHRAE Standard 55 Thermal Environmental Conditions for Human
If you really want to understand thermal comfort and the role of
architecture and building codes and budgets for HVAC system invest your time
with the related reading materials below. It will open your eyes and give you a
better feel for how you should approach your next project.