Building Data Collection: Gather detailed information about the building, including:

• Dimensions and construction materials of walls, floors, and ceilings.
• Window and door sizes and types (single-pane, double-pane, etc.).
• Insulation levels.
• Roof type and color.
• Appliance and equipment loads.
• Occupancy patterns.

Heat Gain Calculations: Calculate heat gains from various sources:

• Solar Radiation: Use solar heat gain coefficients (SHGC) to determine heat gain through windows.
• Internal Heat Gains: Estimate heat generated by occupants, lighting, and appliances.
• Infiltration and Ventilation: Calculate air leakage and fresh air requirements.

Heat Loss Calculations: Calculate heat loss through:

• Conduction: Use the following formula to calculate heat loss through building components:

  Q = U × A × ΔT

  Where: * Q = heat load (BTU/hr) * U = U-factor of the material (BTU/hr-ft²-°F) * A = area of the surface (ft²) * ΔT = temperature difference between inside and outside (°F)

• Infiltration and Ventilation: Calculate heat loss due to air leakage and fresh air requirements.

Sizing the HVAC System: Based on the calculated heat gains and losses, determine the appropriate size of the HVAC system to maintain comfortable indoor temperatures.