Search LiteSpec
Premium Tool

Glass Selection Wizard

Answer four questions about your project and get a realistic, code-compliant glass specification with performance values.

1: Application 2: Location 3: Requirements 4: Results

What is the glass for?

Select the primary application. This determines code requirements, required heat treatment, and glazing type.

Commercial exterior window / curtainwall
Storefronts, curtainwall systems, office windows, commercial facades
Residential exterior window / door
Single-family or multi-family home windows, patio doors, sliders
Overhead / skylight / sloped glazing
Skylights, sloped roofs, canopies, any installation >15° from vertical
Entrance door / sidelite / transom
Swinging glass doors, adjacent sidelites, glass within 24" of a door
Interior partition / office glass
Conference room walls, interior partitions, glass railings, balustrades
Shower enclosure / wet area
Frameless shower doors, bath enclosures, pool barriers, wet area glazing

Where is the building located?

Select your ASHRAE/IECC climate zone. This drives energy code requirements, use IECC 2021 for US projects and NECB 2020 (or your provincial code) for Canadian projects. City examples are provided for both countries.

1–2
Zones 1–2: Very Hot / Hot
US: Southern Florida, Hawaii, Puerto Rico, Phoenix AZ, Houston TX, Tampa FL, New Orleans LA
Canada: No major Canadian cities fall in these zones.
IECC 2021 code: U ≤ 0.40 · SHGC ≤ 0.25 (commercial vertical fenestration)
3
Zone 3: Warm
US: Atlanta GA, Dallas TX, Los Angeles CA, Las Vegas NV, Charlotte NC, Memphis TN
Canada: No major Canadian cities, Canada begins at Zone 4 and colder.
IECC 2021 code: U ≤ 0.35 · SHGC ≤ 0.25 (commercial)
4
Zone 4: Mixed
US: Baltimore MD, Seattle WA, Raleigh NC, Washington DC, Albuquerque NM, Nashville TN
Canada: Vancouver BC, Victoria BC, Kelowna BC (southern BC coastal and inland)
IECC 2021: U ≤ 0.35 · SHGC ≤ 0.40 (commercial) · NECB 2020: verify HDD zone per NECB Appendix C
5–6
Zones 5–6: Cool / Cold
US: Chicago IL, Denver CO, Boston MA, Minneapolis MN, Cleveland OH, Portland OR
Canada: Toronto ON, London ON, Windsor ON (Zone 5) · Ottawa ON, Montreal QC, Calgary AB, Halifax NS, Fredericton NB (Zone 6)
IECC 2021: U ≤ 0.32 · SHGC: no maximum (commercial) · NECB 2020: HDD 3000–5000, verify with NECB Appendix C
7–8
Zones 7–8: Very Cold / Subarctic
US: International Falls MN, Duluth MN, Fairbanks AK, northern Alaska
Canada: Edmonton AB, Winnipeg MB, Quebec City QC, Saskatoon SK, Regina SK, Thunder Bay ON, Sudbury ON (Zone 7) · Whitehorse YT, Yellowknife NWT, Iqaluit NU (Zone 8)
IECC 2021: U ≤ 0.28 (zone 7) / U ≤ 0.25 (zone 8) · SHGC: no maximum · NECB 2020: HDD >5000, most stringent thermal requirements

Any special requirements?

Select all that apply. These affect the glass type, heat treatment, and interlayer recommendations.

Primary performance priority
Energy efficiency
Lowest U-factor, SHGC compliance, energy code first
Maximum daylight
Highest VLT, best LSG ratio
Balanced
Good energy performance and daylighting
Is this in a windborne debris / hurricane zone?
Is sound attenuation a requirement?
Is a fire rating required for this opening?
Recommended specification
,
Specification details
Energy code compliance, 2021 IECC
Applicable standards
Important: These values are representative center-of-glass (COG) performance estimates for the glass configuration described. Whole-window NFRC values, required for energy code compliance, will differ based on your specific frame system and must be verified with the fenestration manufacturer's NFRC-certified product data. Always confirm specifications with a licensed engineer or glass supplier before procurement.
US projects: Verify all specifications against the adopted energy code in your jurisdiction (IECC 2021 or state amendment). Canadian projects: This wizard references ASHRAE climate zones, which align with NECB 2020 (National Energy Code of Canada for Buildings) climate classifications. Canadian projects must be verified against NECB 2020 or the applicable provincial code, Ontario Building Code (OBC), BC Building Code (BCBC), Alberta Building Code (ABC), or equivalent. NECB 2020 fenestration requirements differ from IECC in their structure (HDD-based zones, different U-factor limits in SI units). Consult a local code consultant or the Authority Having Jurisdiction (AHJ). LiteSpec wizard outputs are for educational and preliminary planning purposes only. They do not constitute engineering advice or guarantee code compliance. Performance values are representative of current industry products and will vary by specific manufacturer and product line.
Also try
Energy Savings EstimatorGlass Weight CalculatorBrand & Product Database