Size Every Commercial System Right. From RTUs to Chillers.
The complete commercial load calculation system — block loads, zone-by-zone breakdowns, equipment selection checklists, and ChatGPT prompts for every commercial project type.
Instant download · Covers RTUs, chillers, VAV systems · Based on ASHRAE & Manual J commercial principles
Residential load calcs don't translate to commercial. An undersized RTU on a 10,000 sq ft retail space creates complaints in week one. An oversized chiller wastes thousands in energy per year. Commercial sizing requires block loads, diversity factors, and equipment matchups that most techs were never taught.
Every Commercial Sizing Tool You Need, Built for the Field
Complete Commercial Block Load Calculation System
The full commercial load methodology — from block loads to equipment selection — condensed into practical worksheets any tech or estimator can use in the field.
- ASHRAE block load methodology for retail, office, warehouse, and mixed-use
- Zone-by-zone heat gain/loss templates with diversity factor tables
- RTU & chiller selection worksheet (tons, EER, staging)
- VAV system airflow distribution and static pressure guide
ChatGPT Prompt Templates
30+ prompts for commercial load calcs, equipment selection, energy analysis, and client reporting.
Equipment Matchup Checklists
RTU sizing vs chiller selection decision trees. Know which system fits which building type.
ASHRAE Quick Reference Tables
Ventilation rates, internal heat gain factors, and infiltration calcs for 12 commercial building types.
Instant Download
PDF + editable Excel templates. Works on tablet in the field.
Built for Every Pro Who Touches Commercial HVAC
The Commercial Estimator
You're quoting 20,000 sq ft jobs and guessing on tonnage. One wrong block load and you're under-tonnage on delivery day.
The Senior Service Tech
You've done residential. Now you're getting called on commercial RTUs and chillers and the sizing math is different.
The Facilities Manager
You manage the building. When the contractor quotes a 30-ton chiller for your 15,000 sq ft office, you want to know if they're right.
From Techs and Estimators Who Got the Numbers Right
“Saved us from a $12K mistake.”
“Our estimator was about to spec a 40-ton RTU for a 22,000 sq ft warehouse. The block load worksheet showed 52 tons minimum with the loading dock heat gain. Caught it before submittal.”
Brian K.
Commercial HVAC Contractor, Chicago
“Finally a commercial calc guide that isn't a textbook.”
“I've been doing residential for 8 years. This guide got me up to speed on commercial in a weekend. The ASHRAE quick ref tables alone are worth it.”
Marcus J.
HVAC Tech, Houston
“The ChatGPT prompts actually work.”
“I run commercial energy audits. The prompt templates cut my analysis write-up time in half. The client reports look professional.”
Sandra T.
Facilities Manager, Atlanta
Commercial Jobs Have No Margin for Sizing Errors.
One wrong block load, one undersized unit, one miscalculated zone — and you're back on site pulling warranty work. Get the complete commercial sizing system for $34.99.
Secure checkout · Instant download · 30-day access guarantee