1. What is Relative Heat Gain?

Definition: Relative Heat Gain (RHG) measures the amount of heat energy gained per unit area of a surface.

Purpose: It helps architects, engineers, and building designers evaluate thermal performance of building materials and components.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

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

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

3. Importance of RHG Calculation

Details: RHG helps in designing energy-efficient buildings, selecting appropriate insulation materials, and estimating cooling loads.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: What's a typical RHG value for windows?
A: Standard double-glazed windows typically have RHG values between 200-400 W/m² depending on coatings.

Q2: How does RHG relate to U-values?
A: While U-values measure heat transfer, RHG measures actual heat gain including solar radiation effects.

Q3: When is RHG most important?
A: Particularly crucial in commercial buildings with large glass facades or in hot climates.

Q4: How do I find total heat gain (Q)?
A: Use heat transfer calculations or specialized software that considers conduction, convection, and radiation.

Q5: Does this include internal heat gains?
A: No, RHG typically refers to heat gain through building envelopes from external sources.