Which of the following fenestration exemption statements is NOT true?

The assertion regarding single-pane glass being acceptable in four-season rooms with southern exposure is not true. Building codes generally have stringent requirements about thermal performance, particularly concerning fenestration products, which include windows and doors. Single-pane glass does not provide adequate insulation compared to modern double or triple-glazed options, which significantly improve energy efficiency by reducing heat loss.

The U-factor is a measure of thermal transmittance, and most jurisdictions, including Minnesota, place restrictions on single-pane installations to meet energy efficiency standards. While specific areas of a home may have different allowances based on exposure and usage, single-pane glass is unlikely to meet the energy code requirements for four-season rooms, which are designed for year-round use and comfort.

In contrast, the other statements provide valid exemptions or allowances as per typical building codes. For example, allowing a certain amount of glazed fenestration per dwelling unit for exemption acknowledges practical applications in design while ensuring energy conservation goals are met. Similarly, provisions for area-weighted averages help manufacturers and builders combine various fenestration types while complying with energy codes, thus boosting overall performance. The exemption for one opaque door assembly reflects a reasonable consideration in balancing design choices and regulatory requirements.