How do glass exterior walls compare in lifecycle cost versus traditional façade systems?

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Accepted Answer

Lifecycle cost comparison requires accounting for initial capital cost, operating energy, maintenance, replacement intervals, and residual value. Glass exterior walls typically have higher upfront costs—especially for high-performance IGUs, laminated safety glass, thermally broken frames, and unitized manufacturing—compared with conventional opaque façades (e.g., masonry, insulated metal panels). However, advanced glazing can reduce HVAC energy through improved U-values, SHGC control, and daylighting benefits, which lowers operational expense over decades. Maintenance costs can be higher because glass cleaning (especially at height), sealant replacement, and occasional glass replacement are required; but modern coatings (self-cleaning, low dirt adhesion) and durable framing materials reduce frequency. Durability and lifespan depend on quality of installation and design details; a well-specified glass façade can last 30+ years with periodic maintenance, comparable to masonry when considering retrofit costs. Additionally, transparent façades can increase usable interior daylight, reducing lighting energy and improving occupant productivity—an economic benefit often quantified in lifecycle assessments. For lifecycle cost analysis, use Whole Life Cost (WLC) models to compare net present value (NPV) of alternatives, including energy modeling, maintenance schedules, and expected replacement cycles. The optimal decision balances owner priorities: lower capital cost now versus lower operational cost and higher asset value over time.