1. What is Relative Heat Gain (RHG)?

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

Purpose: It helps evaluate the thermal performance of building materials and design energy-efficient residential structures.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

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

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

3. Importance of RHG Calculation

Details: Understanding RHG helps in selecting appropriate building materials, designing HVAC systems, and improving energy efficiency in residential buildings.

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 residential windows?
A: Standard double-pane windows typically have RHG values between 100-200 W/m², while low-emissivity coatings can reduce this to 50-100 W/m².

Q2: How does RHG affect cooling costs?
A: Higher RHG values mean more heat enters the building, increasing cooling requirements and energy costs.

Q3: What factors contribute to total heat gain?
A: Solar radiation, conduction through materials, air infiltration, and internal heat sources all contribute to total heat gain.

Q4: How can I reduce RHG in my home?
A: Use reflective materials, proper insulation, shading devices, and high-performance glazing to reduce RHG.

Q5: Is RHG the same as U-factor?
A: No, U-factor measures heat transfer rate while RHG measures actual heat gain per unit area.