How does curtain wall glazing selection affect U-value, solar heat gain, and occupant comfort in offices?

Glazing selection is the single most influential variable for thermal and visual comfort in office curtain walls. U-value quantifies conductive heat transfer; lower U-values reduce heat loss in cool seasons and limit heat gain when conditioned space must remain cool. This is achieved by specifying double or triple glazing with low-emissivity (low-E) coatings, warm edge spacers, and inert gas fills. Solar Heat Gain Coefficient (SHGC) defines the portion of incident solar radiation admitted; high SHGC can increase cooling loads and cause glare while low SHGC reduces cooling demand but may decrease useful daylight. Therefore, designers must balance energy and comfort objectives: for deep-plan offices in hot climates, low-E coatings with low SHGC and higher visible light transmittance (VLT) are beneficial; in temperate climates, selective coatings that permit visible light but block infrared offer good compromises. Glazing type (tempered, laminated) and acoustic layering also impact perceived comfort: laminated units can reduce noise and provide post-breakage safety but may slightly alter VLT. The overall curtain wall assembly, including frame thermal breaks and edge seals, influences the installed U-value; poor frame detailing can produce thermal bridging and cold radiant surfaces that affect occupant comfort and perceived draft. Daylighting strategies using frits, interlayers, or external shading optimize glare control and reduce reliance on artificial lighting, improving occupant well-being. Specify whole-assembly certified performance metrics rather than glass-only ratings, and consider dynamic glazing or integrated shading for façades with high solar exposure to maintain both energy efficiency and occupant comfort.

#タイトル

What are the comparative lifecycle costs of stick, unitized, and structural silicone curtain wall systems?

Lifecycle cost comparison between stick, unitized, and structural silicone (SSW) curtain wall systems requires looking beyond initial material and installation expenses to include maintenance, repair risk, replacement, and energy performance over the asset’s life. Stick systems generally have lower shop fabrication costs and greater on-site labour intensity; they are advantageous for phased construction and irregular façades. However, higher site labour and more field joints increase the probability of installation errors and future maintenance for sealants and gaskets. Unitized systems have higher factory fabrication and logistics costs but greatly reduce on-site labour and weather exposure during installation, improving quality control and reducing long-term leak risk. For tall, repetitive façades, unitized systems often offer the best lifecycle value because of reduced schedule risk and fewer field seals. Structural silicone glazing, used where an uninterrupted glass aesthetic is desired, typically incurs higher material and specialist installer costs and demands rigorous quality control and maintenance of silicone joints; silicone joints can be long-lasting if detailed correctly, but failure modes are visually prominent and expensive to remediate. Lifecycle cost must incorporate energy performance attributes: systems with better thermal breaks and high-performance IGUs reduce HVAC energy and operating costs. Also include the cost of periodic resealing, gasket replacement, glass replacement for damaged units, and scaffold/mast access for maintenance. Factoring in durability, risk, and maintenance, a well-executed unitized system frequently achieves lower total cost of ownership for high-rise, repetitive façades; stick systems can be cost-effective for low-rise or highly bespoke façades; structural silicone is premium and suited to signature architectural demands where lifecycle budgeting accounts for specialist maintenance.