Energy Savings From Window Film Calculator

Energy Savings Equation:

\[ \text{Savings (kWh)} = \frac{\text{Area} \times (\text{SHGC}_{\text{without}} - \text{SHGC}_{\text{with}}) \times \text{Cooling Load} \times \text{Hours}}{\text{Efficiency}} \]

Area:

square meters

SHGC Without Film:

SHGC With Film:

Cooling Load:

Watts/m²

Hours:

hours

Efficiency:

Energy Savings:

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1. What is Energy Savings From Window Film?

This calculator estimates the energy savings (in kWh) achieved by applying window film, based on the reduction in solar heat gain coefficient (SHGC) and your cooling system parameters.

2. How Does the Calculator Work?

The calculator uses the energy savings equation:

\[ \text{Savings} = \frac{\text{Area} \times (\text{SHGC}_{\text{without}} - \text{SHGC}_{\text{with}}) \times \text{Cooling Load} \times \text{Hours}}{\text{Efficiency}} \]

Where:

\( \text{Area} \) — Window area in square meters
\( \text{SHGC}_{\text{without}} \) — Solar heat gain coefficient without film (0-1)
\( \text{SHGC}_{\text{with}} \) — Solar heat gain coefficient with film (0-1)
\( \text{Cooling Load} \) — Cooling load in Watts per square meter
\( \text{Hours} \) — Operating hours
\( \text{Efficiency} \) — Cooling system efficiency (0-1)

Explanation: The equation calculates the reduced cooling energy needed due to the window film's improved solar heat rejection.

3. Importance of Energy Savings Calculation

Details: Calculating potential energy savings helps justify window film investments and predict payback periods for energy efficiency upgrades.

4. Using the Calculator

Tips: Enter all values in the specified units. SHGC values typically range from 0.3 to 0.8 for untreated glass. Efficiency is often between 0.7-0.9 for modern systems.

5. Frequently Asked Questions (FAQ)

Q1: What is SHGC?
A: Solar Heat Gain Coefficient measures how much solar heat passes through a window. Lower SHGC means better heat rejection.

Q2: Where can I find SHGC values?
A: For untreated glass, check manufacturer specs. For films, consult the film manufacturer's performance data.

Q3: How accurate is this calculation?
A: It provides a reasonable estimate but actual savings depend on climate, orientation, shading, and usage patterns.

Q4: Can this be used for heating season?
A: No, this only calculates cooling energy savings. Films may reduce winter heat gain, which could increase heating costs.

Q5: What's a typical payback period?
A: Payback varies but often ranges from 3-7 years in hot climates with high cooling costs.