Hvac Design - Calculations Excel

Input original conditions (CFM1, SP1, BHP1) and a new RPM. Let Excel calculate all three new values instantly. Lock the original values with $ references.

Create drop-down lists (Data Validation) for wall types, orientations, and hours. Use VLOOKUP or XLOOKUP to fetch CLTD values from a hidden table. This turns a static sheet into a dynamic tool.

Modern HVAC design typically focuses on four primary calculation areas: hvac design calculations excel

This is the most critical step, determining the required capacity to maintain indoor comfort. HVAC Load Calculator - Manual J Calculation | ServiceTitan

These determine the total heating or cooling power required. A common formula used in Excel sheets is: Input original conditions (CFM1, SP1, BHP1) and a new RPM

Once the room load is known, you need airflow (CFM). The fundamental equation is:

Store a friction loss vs. CFM vs. diameter table. Use INDEX/MATCH or linear interpolation to find the nearest duct diameter for a given CFM at your target friction rate. Create drop-down lists (Data Validation) for wall types,

Q=Area (sq. ft.)×Heat Load Factor (BTU/hr per sq. ft.)cap Q equals Area (sq. ft.) cross Heat Load Factor (BTU/hr per sq. ft.)

| Tab Name | Purpose | | :--- | :--- | | | Location, outdoor design conditions, indoor setpoint, wall/glass areas | | CLTD_Tables | Raw lookup data for walls, roofs, glass, and solar factors | | Room_Loads | Per-room sensible/latent heat gain calculations | | Air_System | CFM per zone, supply temp, fan selection | | Duct_Design | Branch & main duct sizes, velocity, pressure drop | | Pipe_Design | GPM, diameter, velocity, head loss | | Equipment_Schedule | Links to final selections (chiller, boiler, AHU, FCU) | | Report | Clean, print-ready summary with conditional formatting |