Last Word – Feb 2020
It would seem two identical homes or buildings constructed at the same time, in the same area, with the same design criteria should achieve about the same energy consumption, indoor air quality, and comfort levels. The reality is they can be vastly different based on a myriad of factors. You could say that each building has a distinct “DNA.”
The most obvious factors affecting a structure’s DNA include the building orientation, natural shading, terrain, etc. Less obvious differences include a laundry list of significant variations and changes that may have occurred both during construction and after the building is occupied.
Let’s take a look at other factors that contribute to each building’s uniqueness.
While the same building components may be used on two identical structures, each building’s characteristics can be changed by how the materials were installed. Was the insulation in walls and unconditioned spaces installed properly? Are there gaps in the insulation and sheathing? Was it over-compressed in some cavities? Was blown-in insulation applied at a consistent height? Were all penetrations sealed properly?
“What better way to differentiate your contracting business than to uncover and offer to solve these issues that exist in more than 80% of homes in North America?”
Next add variables such as skill differences between crews, how late in the day certain work was completed, and temperatures at the time of construction. The structure’s DNA continues to morph before it’s even finished.
As a building is occupied, its DNA continues to mutate and evolve. For example, other work may be performed that can affect envelope penetration and insulation values. Maybe the cable or alarm contractor messed up the insulation integrity in the attic. Maybe new fans installed in kitchens and baths changed building pressures, and so forth.
Then there are changes made by occupants and how they use different spaces. Some block off registers in unused areas; rooms are remodeled or added; fireplaces and freestanding “comfort” appliances are brought into the equation, etc. The DNA continues to mutate and devolve.
HVAC System DNA
Starting at birth -- i.e. construction -- an HVAC system’s genetics are greatly impacted by its own set of variables. These include different installation crews with different skill levels, low-bid pressures to reduce labor and quality of materials, a hot attic during installation, and more.
The air distribution system also has many unique variables including how well joints were sealed, and how tight the flex was stretched. Was there enough radius and support on turns? Was it compressed? Was a flex duct running horizontally connected to a straight boot over a ceiling register without an elbow?
Then you add in things like little or no air balancing (if dampers are even installed), poor sealing around boots and registers, improper refrigerant charge on short or long line sets, and the DNA devolves some more.
Once a building is occupied, we see similar problems to the envelope issues. Maybe the cable or alarm guy crushed a return or smashed or even disconnected a supply run. Some cut into returns and use them as chases for their wires.
Can you see how every building has its own distinctive DNA? The question is, do you continue to treat each unique home or building the same way based on rules of thumb, or design-oriented sizing? Isn’t that a disservice to your customers?
There truly is only one proper way to identify these mutations and defects so they can be corrected. Just like a doctor who uses tests to diagnose diabetes, cancer, heart disease, and so forth, an HVAC professional must learn how to test every aspect of an HVAC system.
You must also consider the impact of the building as it stands. You need to know when to apply which testing as you delve into the causes of these defects so you can offer true solutions.
What better way to differentiate your contracting business than to uncover, and offer to solve these issues that exist in more than 80% of homes in North America? Today you have access to the best instruments and training available to take the “High-Performance” approach and improve the homes and buildings you work on every day.
Why not be that contractor who helps their customers live and work in the safest, healthiest, most comfortable, and energy-efficient indoor environments. After all, If You Don’t Measure, You’re Just Guessing!
Dominick Guarino is CEO of National Comfort Institute (NCI), (www.nationalcomfortinstitute.com), one of the nation’s premier Performance-BasedTM training, certification, and membership organization focused on helping contractors grow and become more profitable. His e-mail is [email protected]. For more info on Performance-Based ContractingTM go to WhyPBC.com or call NCI at 800/633-7058.