What's the paradox?

Building energy-efficient houses benefits everyone. Still, specific building codes ignore optimal efficiency, limit effective design options, and impose increased costs.

The latest International Energy Conservation Code (IECC) leads to using costly products of lesser quality. In the US, for instance, the National Fenestration Rating Council’s (NFRC) testing process has manufacturers test, rate, and label product lines based on a computer model of one size instead of the actual house sizes and glass types. However, the actual windows and doors perform substantially higher than the NFRC-tested models, whose sizes refer to tract housing products, not custom-built homes.

For example, the test uses sliding-door dimensions of 6.6 x 6.6 ft. (43 sq. ft.), yielding a 0.47 U-value. EPAL’s most purchased sliding doors are 24 x 12 ft. (288 sq. ft.), and testing them yields a 0.32 U-value. So, the NFRC value leads to pointless and expensive upgrades, like installing high-performance glass and thermally broken aluminum.

The case against high-performance glass

In theory, upgrading to high-performance glass seems wise, though costly. In reality, any intended high-end design gets sidetracked as windows look darker, greener, or more reflective, resulting in houses that look more like office buildings than luxury residences.

The case against thermally broken aluminum

Thermally broken aluminum is ideal for extremely cold climates, where compromises are few, considering its significant advantages over wood, steel, and PVC. However, exaggerating U-value significance leads to products that undermine a house’s aesthetic features and create building challenges:

  1. Practical challenges
  • In dry climates, extrusion cavities are heated regardless, so thermal efficiency is less of a factor
  • Radical temperature changes result in bowing (thermal twisting)
  1. Cost challenges
  • Thermally broken aluminum products are more costly to build
  • Custom finishes require considerable additional charges
  1. Durability challenges
  • Added plastic weakens product structure, affecting its operation
  • Product sizes are limited despite high-performance verticals
  • EPAL does not use thermal breaks in its basic product lines to keep them more robust and cost-efficient
  1. Longevity challenges
  • Materials are more volatile due to thermal shrinkage
  • Connection points (aluminum/plastic) are less durable than solid aluminum
  • Maintenance capacity depends on the fragility of plastic parts
  1. Aesthetic challenges
  • Black plastic lines break design uniformity
  • Bulk is added to make up for the weakened structure
  • Products may contain multiple snap-in components

Achieving compliance

  1. Identify the compliance method
  • For tract houses or remodeling projects, EPAL uses the prescriptive method
  • For custom projects, EPAL uses a computer model to identify tradeoffs of building components (performance method) with the required U-value for the prescriptive method as the starting point
  1. Keep costs to desired levels
  • EPAL discloses the NFRC energy test results (SHGC, U-value)
  • EPAL’s energy consultant incorporates the values into the project by identifying standalone parts to be upgraded to maintain energy efficiency levels without messing with the design and raising costs
  • EPAL offsets efficiency by changing smaller windows/doors instead of the larger, more costly sliding and hinged systems
  1. Carefully consider every adjustment

EPAL provides a free custom energy report with every quote:

  • A custom report is the most accurate compliance tool for custom builds that require optimal performance, unique aesthetics, and mitigated costs
  • EPAL uses the NFRC computer modeling software to assess energy efficiency for the project’s actual sizes
  • EPAL’s authorized dealers provide the custom energy report upon request