Heat Gain on Walls (\( Q_w = A \cdot R_t \cdot (T_o - T_i) \)):

Where:

• \( Q_w \) is the heat gain from walls, in watts (W).
• \( A \) is the wall surface area, in square meters (m²).
• \( R_t \) is the thermal transmittance, in watts per square meter per degree Celsius (W/m²-°C).
• \( T_o \) is the wall outside temperature, in degrees Celsius (°C).
• \( T_i \) is the wall inside temperature, in degrees Celsius (°C).