Ceiling Insulation
- Compliance with the R-value requirement decreased slightly from 90% in Phase I to 88% in Phase III.
- U-Factor compliance improved from 41% in Phase I to 71% in Phase III.
- While ceiling insulation levels were generally adequate, installation quality (IIQ) remains a concern; U-Factor compliance rates were lower than R-value compliance rates.
- Phase II training focused on improving IIQ, leading to notable gains in Phase III; however, installation quality continues to be an area for improvement.
Duct Leakage
- Reducing duct leakage was a key focus of Phase II education and training activities.
- Duct leakage compliance improved in Phase III; increased compliance for ducts outside conditioned space contributed to greater measure-level savings and a higher observed EUI in Phase III.
- Overall compliance increased as more ducts were installed within conditioned spaces; however, compliance for ducts located outside conditioned space decreased.
Envelope Air Leakage
- In Phase I, reducing envelope air leakage rate was identified as an area for improvement; this became a focus of Phase II education and training activities.
- Minimum observed envelope air leakage rate increased from 0.51 ACH50 in Phase I to 1.85 ACH50 in Phase III; the average improved from 5.6 ACH50 to 4.1 ACH50, meeting the state requirement of 7 ACH50.
- Compliance improved from 70% to 97%; this suggests that Phase II activities were successful.
Foundation & Foundation Insulation
- Basements:
- In Phase I, none of the basement walls with continuous insulation met the requirement (12 observations); most walls with cavity or combined insulation did comply (34 observations), indicating insufficient continuous insulation.
- 18% of observations did not meet the U-Factor requirement in Phase I; this was primarily due to R-13 cavity insulation paired with Grade II or III installation quality, highlighting IIQ issues.
- In Phase III, the average basement wall U-Factor worsened, but overall compliance improved significantly; remaining challenges include an increase in uninsulated walls and continued U-Factor failures despite adequate insulation, suggesting installation quality below Grade I standards.
- Floors:
- A majority of observations in both phases had Grade II or III installation quality from an assembly perspective.
- While cavity insulation levels (R-value) were generally achieved in Phase I, overall assembly performance (U-Factor) showed room for improvement and was a focus of Phase II training.
- In Phase III, cavity insulation compliance declined and the average U-Factor increased from 0.05 in Phase I to 0.13 in Phase III; this indicates a deterioration in floor insulation performance.
- Slabs:
- In Phase I, 80% of slab edge insulation observations did not comply; this included several cases with no slab insulation present. Slab insulation was a focus of Phase II education and training.
- By Phase III, average slab insulation levels decreased and the compliance rate was cut in half to 10%, indicating that slab insulation remains a significant challenge.
Lighting
- In Phase I, only 31% of field observations met lighting requirements; despite targeted education and training in Phase II, compliance increased to just 35%.
- Lighting remains a continued opportunity for energy savings.
Wall Insulation
- Around 50% of homes had R-13 cavity insulation, meeting the code requirement; most of the remaining observations exceeded R-13.
- Despite Phase II education and training efforts, installation quality (IIQ) remains a concern; U-Factor compliance improved slightly from 28% in Phase I to 38% in Phase III.
Windows
- Although there is no SHGC requirement in Climate Zone 4, the observed SHGC values in both Phases I and III were similar and nearly met the prescriptive requirement for more stringent climates (Climate Zones 1–3).
- Fenestration products showed a high compliance rate; nearly all observations met or exceeded code requirements, representing one of the study’s most significant findings.
