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Calcimator

Low-E Coating Calculator

Analyze Low-E coating performance including U-factor reduction, SHGC, daylight factor, and seasonal performance by surface position.

Inputs

Results

U-Factor Reduction

41.26%

SHGC Value

0.44

Light-to-Solar Gain Ratio1.59
Winter Performance90%
Summer Performance48%
How to Use This Calculator
  1. Enter the Coating Emissivity (typical Low-E range: 0.04–0.15), Solar Transmittance, and Visible Transmittance.
  2. Select the Coating Position: Surface 2 (heating climate) or Surface 3 (cooling climate).
  3. Review U-Factor Reduction percentage to quantify the insulation improvement from the Low-E coating.
  4. Check SHGC Value to confirm solar heat control for your climate and orientation.
  5. Use the Light-to-Solar Gain Ratio to balance daylight transmission against solar heat gain.

How the result changes with Coating Emissivity

Coating EmissivityU-Factor ReductionSHGC Value
0.140.97%0.44
0.3122.25%0.44
0.559.92%0.44
0.762.54%0.44

What each input means

Coating Emissivity
Emissivity of the Low-E coating (0.04-0.15 typical; lower = better insulation).
Solar Transmittance
Fraction of solar energy transmitted through the glass (0-1).
Visible Transmittance
Fraction of visible light transmitted (higher = more daylight).
Coating Position
Surface 2 = inner face of outer pane (better for heating). Surface 3 = outer face of inner pane (better for cooling).

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Coating Emissivity = 0.1, Solar Transmittance = 0.4, Visible Transmittance = 0.7, Coating Position = 1 = 4 input(s) provided
  2. Calculate U-Factor Reduction
    U-Factor Reduction
    41.26 = 41.26
  3. Calculate SHGC Value
    SHGC Value
    0.44 = 0.44
  4. Calculate Light-to-Solar Gain Ratio
    Light-to-Solar Gain Ratio
    1.59 = 1.59
  5. Calculate Winter Performance
    Winter Performance
    90 = 90

Engine last updated . Checked against 1 independently-derived test — how we verify calculators.

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