The Zero Thermal Transference Myth
Filling The Energy Gap
Why R-Value Alone Isn’t Enough
If half of the money you spend on utilities is going out through porous exterior walls, all the correctly installed fiberglass and cellulose insulation in the world won’t make the tiniest bit of difference. These products don’t stop convection.
Even worse, they harbor and contribute particulates into the envelope, creating unnecessary health risks.
R Value Limitations
in Exterior Framing Assemblies
The R value measures an insulation’s ability to limit conductive heat flow (heat transferred through it). Keep in mind though, the primary method of heat transfer is not conductive heat flow — it’s air leakage (convection).
On average, air-infiltration accounts for 40% or more of a building’s energy loss.
Thermal transference takes place through the walls, ceilings and roof of a building, mainly via the structural members. This is because of the higher thermal conductivity of the materials used for the building’s frame; typically steel or wood. However, the amount of money you pour into the epidermal layer of your building to reduce thermal transference to “zero” begins approaching astronomical proportions.
Beyond a certain point it’s hardly worth the cost, because air convection takes over as the principal energy loss factor. At some point it’s easier and less expensive to make your own energy to fill the Energy Gap.
Zero Myths, Actually
It should be no surprise that the Zero Factor in energy efficiency, and energy generating NetZERO and NetPLUS buildings is not a constant. While it may be theoretically possible to achieve and maintain zero convective air infiltration, a zero thermal transference of energy between the inside and outside environments, and a perfect balance between energy generation and consumption, the actual incidence of maintaining these equilibration is statistically zero. Perfection is, after all, fleeting.
However you want to say it; in the final analysis, at the end of the day, a choice has to be made regarding the “balance of the power.” The way we see it at Abide Systems, creating a diaphragm that performs to a higher standard, thereby reducing operating energy needs to the bone-minimum, means you’ll need to invest less in energy generation to achieve a NetZERO balance.
That in-turn makes it easier to go just a little further and become NetPLUS: Energy Independent. As renegades in the building industry there’s one “law” we certainly do believe in…
The Law of Diminishing Returns
Insulation only does so much to prevent conductive heat flow. Beyond a certain point, increasing insulation R value makes very little difference, if any. In fact, the cost of increasing R value alone can actually far outweigh the energy savings that result, meaning it will take much longer to break even.
The Best Way to Increase Efficiency?
Combine R value with a contiguous and effective air barrier. Merely increasing the exterior walls R values in between all those tiny holes won’t help. While spray and injected foam insulation provides both in a single step, we use it as a primary means of insulating and even more important – it’s a secondary means of creating and maintaining an effective air infiltration barrier.
Why is this “more important?” Because the exterior air barrier is usually compromised to some degree by the time the construction phase is complete, and often during the life of the building more holes are made. The next reason is because during the life of the building it’s going to move – and settle. When it settles, cracks are created and the building’s assembled parts separate from each other to some degree. This would normally create air-seal issues, but properly applied foam insulation prevents these unseen penetrations and uncontrolled air infiltration.
Abide Systems carefully considers which insulation type to use in each location in the structure. 2.0pcf foams might be too rigid to use for air sealing purposes in new construction, because when the building settles this more-brittle foam may crack. Different formulations by various manufacturers may combine characteristics of .5pcf open cell and 2.0+ closed cell to achieve a higher degree of flexibility and increase R values at the same time.
Depending on the system that’s appropriate for the project, we may strategically use flexible .5pcf and rigid 2.0pcf foams to achieve optimum R-values and maximize air sealing capabilities.
All of our approved foam product manufacturers offer lifetime warranties on the insulation products we install. For as long as the building stands, the manufacturers stand behind their products. The warranties stay with the building – not the occupants or owners – regardless of how many times it may be transferred. Abide Systems maintains accessible records, so if previous owners forget to transfer the warranty with the building, the new owners can easily get updated. They’ll receive the same access to service and maintenance programs that the initial owners had enjoyed before the title was transferred.
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The Bottom Line?
We exclusively use spray and injected foams for insulation in our building component systems.
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To find out what ASHRAE says your R-value should be – and for more on how, where and why we use certain types of foam, click here: Insulation Applications