1. What is Relative Heat Gain (RHG)?

Definition: RHG measures the amount of heat gain per unit area, expressed in Watts per square meter (W/m²).

Purpose: It helps engineers and architects evaluate thermal performance of building materials and systems.

2. How Does the RHG Calculator Work?

The calculator uses the formula:

Where:

• \( RHG \) — Relative heat gain (W/m²)
• \( Q \) — Total heat gain (Watts)
• \( A \) — Surface area (square meters)

Explanation: The total heat gain is divided by the surface area to determine the heat gain per unit area.

3. Importance of RHG Calculation

Details: RHG calculations are crucial for designing energy-efficient buildings, selecting appropriate insulation materials, and optimizing HVAC systems.

4. Using the Calculator

Tips: Enter the total heat gain in Watts and surface area in square meters. Both values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical RHG value for windows?
A: Standard double-pane windows typically have RHG values between 200-400 W/m², while low-emissivity coatings can reduce this to 100-200 W/m².

Q2: How does RHG differ from U-factor?
A: U-factor measures heat transfer rate, while RHG measures actual heat gain per unit area, accounting for both conduction and solar radiation.

Q3: When would I need to calculate RHG?
A: RHG calculations are essential for building envelope design, energy modeling, and compliance with energy codes.

Q4: What factors affect RHG?
A: Solar radiation, material properties, surface color, orientation, and shading all influence RHG.

Q5: How can I reduce RHG in a building?
A: Use reflective surfaces, shading devices, high-performance glazing, and proper insulation to reduce RHG.