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It’s All About BS: Building Science

Infrared House

If you ask tradespeople or contractors about how and why they perform a specific task they do regularly in a certain way--like hanging HVAC ducts up high on the rafters in the attic--you usually get one of two responses.

  1. Lots
    of people will fall back on their training or early experience: “I learned to
    do it this way when I worked for _______ (fill in the blank), and I have done
    it like that ever since.”
  2. Others
    justify their methods through preconceived ideas that might sound plausible but
    that may or may not have any basis in fact, such as “the airflow is better when
    ducts are mounted up high because the air shoots down from the duct into the

The truth is, many of the tradespeople we rely on to build
quality homes seldom question the methods they use daily. Installers and
builders continue to do what they have done for years, without much thought
about why they do it or if there might be a better way. Honestly, I can’t judge
them. I think we have all been guilty of this at some point.

But in order to work and be taken seriously, building performance
contracting has to be rooted in science. This means relying on measurable and
repeatable results to verify your conclusions, and adjusting how you do things
accordingly. To be scientifically valid, someone else should be able to look at
what you do, repeat it, and get the same results. A final test is peer review,
in which other experts in the field go over your results and confirm that you
are not fabricating the truth.

This process works. For example, over the years a number of
researchers have claimed to discover methods to perform room temperature or
cold-fusion. In every case, a peer review debunks their findings. Hopefully,
someday the claim will be valid, but in the meantime, we’re lucky to have a
process that keeps us from buying into things that don’t work.

In my experience, contractors usually intend to do the best job
they can, but they don’t always have the right information to support or
justify their methods. I can’t tell you how many contractors I have met who are
intrigued by building science after they learn how many of the things they have
been doing for decades are not the optimal solution. I think this is one of the
reasons this field appeals to an older, more experienced generation.

Building science isn’t very old: it’s easy to forget that the
industry has only been around for 30 or 40 years. In the beginning, building
science was driven by the desire to confirm that the investments that
governments and interested stakeholders were making in energy efficiency had
value by measuring what was happening in the field.

The initial questions were pretty basic: Which is a more
efficient way to heat a home, natural gas or electricity? How much insulation
should be used in an attic for our climate zone? Then the questions evolved and
focused on occupants and indoor air quality. How tight can we make our homes?
And how much ventilation do we need to be safe? It’s a bit ironic that decades
later, there is still debate over these fundamental questions.

It turns out the only way to know if you are saving energy is to
measure the situation before you make changes and then measure it again after
you make improvements. Researchers had to develop new tools to evaluate some of
these underlying assumptions. The most notable is a blower door, a large,
calibrated fan used to pressurize a building to determine how much air enters,
or infiltrates, through cracks and other pathways to the exterior.

Today there are all kinds of sophisticated tools to help
understand how buildings perform in a variety of situations. Technicians use
calibrated fans, moisture and gas sensors, infrared cameras, and monitoring
devices to measure how buildings perform. Testing and relying on measured data
is one of the fundamental principles of building science and the home
performance industry.

In this age of super-powerful computers and advanced materials,
it’s no surprise that these days many people also use computers and
sophisticated software to predict building energy use and post-upgrade energy
savings. The problem is that energy use in buildings is a very complicated
subject.  Multiple interdependent
interactions affect results. I often tell folks that energy models are a bit
like weather forecasts: you can get an excellent idea of what you think will
happen, but sometimes a small change you didn’t anticipate can have a drastic
impact. I used to have a colleague who was previously a “propulsion specialist”
(better known as a rocket scientist). He used to joke that building science was
not rocket science; it was harder. There are many situations where energy
models and software are helpful, such as predicting energy pre-construction,
but nothing beats measurable and repeatable results.

As the industry evolves, we need to make sure that it continues to rely on scientific evidence over assumptions. This is especially true as new concerns like health-related indoor air quality and decarbonization take hold in the industry. Most of the health impacts of buildings are directly related to moisture and ventilation, which affect indoor air quality. The majority of greenhouse gas (GHG) reduction efforts focus on electrification.

I am encouraged by both of these efforts. I think anything that
brings attention to the dramatic impact our buildings have on the occupants and
our environment is a good thing. I am a little concerned, though, that in our haste
to promote these trends, data and the scientific method are sometimes being
left behind. It’s easy to get excited about a new technology or idea and
aggressively promote its adoption, but to make sure we can deliver positive
results, we need to ensure that any information circulating in the industry
relies on facts and measurable data.

Our industry needs to scale and scale fast to meet the demands of our ever-changing world. There are billions of dollars allocated to improving our buildings and reducing their impact on occupants and the environment. There will be winners and losers in this transformation. We are pushing new ideas and supporting practices that will be vehemently opposed by powerful entities. The worst thing we can do is to promote technology or ideas that are not well tested. We need to deliver results, and the best way to do that is to rely on measured results and the scientific method. In the end, we need to let the facts and science do the talking in the push to a clean energy future.

What are your thoughts? Email us at

Charles Cormany
Executive Director
Efficiency First California