Windows require both conduction calculations and Solar Heat Gain Coefficient (SHGC) factors to account for direct sunlight.
Are you calculating for a or commercial property?
Slab-on-grade, over unconditioned crawlspaces, or basements.
Unlike dynamic software, Excel doesn't always account for "shading" that changes throughout the day unless complex macros are used. Ready to level up your HVAC design? hvac calculation excel sheet 2021
Engineers, contractors, and energy auditors continue to rely on spreadsheet-based calculators for several distinct reasons:
Modern calculations generally break down into two main thermal categories:
[Gather Blueprints] ➔ [Input Climate Data] ➔ [Measure Take-offs] ➔ [Define Internal Gains] ➔ [Analyze CFM & Tonnage] Windows require both conduction calculations and Solar Heat
If you are building your own sheet or auditing an existing one, these are the "big three" formulas that drive the logic: Total Heat Load ( The sum of all sensible and latent gains. Airflow (CFM): 🚀 Why Use Excel Over High-End Software?
Q=U×A×ΔTbold cap Q equals bold cap U cross bold cap A cross bold cap delta bold cap T = Heat transfer rate (BTU/hr or Watts)
Compares the calculated loads against manufacturer performance data to select specific AC or heat pump models. Psychrometric Analysis: Uses scatter plots and interpolation formulas (like ) to analyze air properties like humidity and enthalpy. Air Conditioning Contractors of America - ACCA Essential HVAC Formulas for Excel Unlike dynamic software, Excel doesn't always account for
The number of people typically in the space (allocated at roughly 250–400 BTU/hr per person).
An oversized HVAC system cycles on and off too frequently, leading to poor humidity control and premature equipment failure. Conversely, an undersized system will fail to keep the building comfortable during peak summer or winter days. A detailed Excel calculation ensures you account for every heat gain and loss factor, including: Building orientation and solar heat gain. Insulation R-values for walls, ceilings, and floors. Window U-values and solar heat gain coefficients (SHGC).
A comprehensive HVAC calculation sheet should generally be divided into distinct tabs or sections. If you are building your own or downloading a template, ensure it includes the following: