Quick answer: Florida Building Code Energy Conservation chapter (based on IECC) sets U-factor and SHGC limits for commercial fenestration. Climate Zone 1 (South Florida) requires U-factor ≤ 0.50 and SHGC ≤ 0.25 for most vertical glazing. Climate Zone 2 (rest of Florida) is slightly less strict. Compliance paths include prescriptive (component-by-component limits), performance (whole-building modeling), and trade-off (area-weighted average).
Climate Zone 1 (South Florida, including Miami-Dade, Broward, Palm Beach, Collier, Lee, Hendry, Monroe, Glades): strictest energy code. Climate Zone 2 (rest of Florida): slightly less strict. Boundaries follow county lines.
Climate Zone 1: U-factor ≤ 0.50. Climate Zone 2: U-factor ≤ 0.55. Most commercial low-E insulated glass easily achieves U-factor 0.30-0.45, providing significant margin to the code minimum.
Climate Zone 1: SHGC ≤ 0.25 for most projects (slightly higher for north-facing only). Climate Zone 2: SHGC ≤ 0.27. SHGC compliance is the binding constraint in South Florida — it drives low-E specification.
Florida energy code doesn't require minimum VLT, but most architects target VLT 35-70% for daylight quality. High-performance low-E products (Solarban 70XL, SunGuard SN 68, VRE-46) deliver this VLT while meeting SHGC ≤ 0.25.
Prescriptive: each component must meet the table limits. Performance: whole-building energy modeling demonstrates equivalent or better performance. Trade-off: area-weighted average across all fenestration meets the limit. Most commercial projects use prescriptive.
1) Specifying clear vision glass without low-E coating (SHGC 0.55-0.70, fails Zone 1). 2) Single-pane glass (U-factor 1.10, fails everywhere). 3) Glass at building corners (higher wind load) sometimes incorrectly specced from interior wall sections. 4) Skylights treated as vertical fenestration (different limits apply).
AHJs verify energy compliance via REScheck (residential) or COMcheck (commercial) reports submitted with the permit application. Glaziers don't directly produce these reports, but they provide the U-factor and SHGC values that the energy consultant inputs.
FBC Energy Conservation chapter requires Climate Zone 1 (South Florida) commercial vertical fenestration to meet U-factor ≤ 0.50 and SHGC ≤ 0.25. Climate Zone 2 is slightly less strict.
Typical high-performance low-E commercial glass has SHGC 0.20-0.27 — well within Florida Climate Zone 1 requirement of ≤ 0.25. Products like Solarban 70XL, SunGuard SN 68, and Viracon VRE-46 are commonly specified.
No — single-pane clear glass has U-factor around 1.10, far above the 0.50 limit. Commercial buildings require insulated (double-pane minimum) glass to comply.
Energy code compliance is verified via COMcheck reports submitted with the permit application. An energy consultant or design professional prepares these. The glazier provides the U-factor and SHGC values.
Not automatically — impact glass can be specified with or without low-E coating. Most modern impact assemblies include low-E to meet energy code, but verify the specific product specification.
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