03 - Determining Air Conditioning System Capacity

Send us Fan MailLearn BTU capacity concepts, ACCA Manual J/S basics, sizing tolerances, and the risks of under- or over-sized cooling systems.Show Notes:Episode Overview: Inspectors are not required to confirm exact BTU capacity but should understand capacity concepts to assess potential sizing issues. Learn ACCA Manual J (load calculation) and Manual S (equipment selection), ideal sizing tolerance (within ~½ ton), and risks of improper sizing. Includes rules of thumb and geographic variability cautions.What You'll Learn: • ACCA Manual J (loads) and Manual S (capacity) workflow • Ideal sizing tolerance: within ~½ ton of calculated capacity • Risks of under-sizing (insufficient cooling, high energy use) • Risks of over-sizing (short cycling, poor humidity control, discomfort) • Common rules of thumb (400-800 BTU per 1,000 ft²) and their limitations • Geographic and climate variabilityKey Takeaways: ✓ Understand capacity concepts without performing Manual J calculations ✓ Recognize signs of over-sized or under-sized systems ✓ Use rules of thumb cautiously and understand their limitationsIRC Code References: ACCA Manual J & S; IRC 2018 Chapter 14Study Tips: Practice estimating capacity for sample homes using rules of thumb, then compare to actual installed capacity.Intro This episode is brought to you by GetSync.pro This episode is hosted by Charlie Bellefontaine of Chicagoland Home InspectorsFor complete training with visual materials, practice exams, and certification support, visit nhiexamprep.com© 2025 National Home Inspector Exam Prep Podcast. All rights reserved.