You can literally watch the heat leaving a house with a substandard envelope.
“When I’m doing an energy audit, I’ll take my thermal imaging camera and one of the things that you’ll notice is every framing member stands out like a sore thumb,” says Randy Williams, an energy auditor in Grand Rapids, Minn.
Yes, heat can still seep out through the framing members even with cavity insulation. That’s money out the window — or the wall, in this case.
Enter continuous insulation (CI).
CI provides a consistent thermal barrier with a high R-value to minimize where heat escapes through structural elements like studs. Unlike cavity insulation, CI is wrapped around the exterior of the sheathing. Think of it like a jacket for the house.
More and more jurisdictions are requiring CI in their building codes. But you don’t have to wait for your city or county building departments to follow suit. Williams says proactive builders are incorporating the material to achieve significant energy savings and advanced durability ahead of impending code changes.
A performance path to code compliance
As Williams explains, there are two paths to meeting energy requirements: a performance path and prescriptive path.
The prescriptive path follows the code’s written language to a T. The performance path achieves the same objectives but allows more flexibility in how builders meet energy requirements. This can involve trade-offs, such as using higher insulation levels in some areas to compensate for larger windows so long as the total energy efficiency meets the required standards. This approach can be more cost effective.
That’s the beauty of CI, Williams says. It provides another way for builders to be more strategic.
“For instance, you could increase air tightness and wall R-values to decrease R-values in ceilings,” Williams says. “Adding CI can help with those trades.”
Passing the blower door test
Blower door tests are being used to qualify new and existing homes for energy efficiency tax credits for both builders and homeowners. These incentive programs have specific requirements, relative to climate, concerning air entering or leaving a building through leaks and gaps.
Blower door tests measure air leakage through the number of air changes per hour at a specified pressure, usually 50 Pascal or ACH50. (That’s equal to a 20 mile-per-hour wind blowing on the house from all sides.) Up to seven air changes per hour (an ACH50 of 7) is considered “very loose.” An ACH50 of 1 or less is “very tight.”
A good target for most buildings is an ACH50 of 3.
Williams aims for better. In his building projects, he routinely scores an ACH50 of 1, and that’s due, in part, to his use of CI. With the material, “it’s very simple for me to get to that ACH50 of 1,” he says.
Henry’s Blueskin VPTech makes a more airtight building, helping achieve ACH50 values far below the maximum allowed by ASTM E779 or ASTM E1827 testing.
A 2-for-1 solution
Builders no longer need to fuss with two layers of protection: one for the thermal barrier and another for the water-resistive barrier (WRB). With Henry R-Tech and Blueskin VPTech, you’re getting a material that pulls double-duty: It’s both a CI and a WRB. That means less labor and faster installation.
“One trip around the home and you’ve both insulated and installed the water-resistive barrier,” Williams says.
Blueskin VPTech represents a first-of-its-kind innovation in building envelope solutions combining a water-resistive barrier (WRB), continuous insulation (CI), and seam sealing in a single, integrated panel, significantly improving energy efficiency, and reducing installation time and associated labor costs by up to 30%. Click here to learn more.