What We Do

About Manual J Design Studio

Precision Load Calculations. Expert HVAC Design. Real Human Support.

At Manual J Design, we specialize in providing code-compliant Manual J, S, and D reports for residential HVAC systems. Our mission is simple: make accurate HVAC design easy, accessible, and fast for professionals who can’t afford to get it wrong. 

Whether you’re a contractor preparing permit-ready load calculations, an architect designing a new build, or a homeowner wanting to make smart system decisions, we’re here to deliver clarity and confidence every step of the way. 

Manual J Custom Design Services

Manual J Design Studio was built by HVAC pros FOR HVAC Pros

We’re not just software; we’re real people who understand what it’s like to sit in on code inspections, meet deadlines, and troubleshoot installations. That’s why thousands trust Manual J Design Studio over free or semi-automated tools like CoolCalc. We offer the expertise and personal support that design software alone can’t deliver. 

Why Builders, Tech, and Designers Choose Us

We’re proud to be a trusted HVAC design partner across the U.S., helping streamline compliance and improve performance for residential projects of every scale. We Deliver!

  • Manual J Load Calculations that are ACCA-certified and jurisdiction-ready 
  • Manual S Reports for accurate equipment sizing 
  • Manual D Layouts that eliminate guesswork and optimize airflow 
  • Faster Turnarounds than most software-based solutions 
  • Live, human support—not just a help article or chatbot 

Manual J Load Calculations

 ACCA-compliant reports to ensure accurate sizing and system efficiency

Manual S Equipment Selection

 Match heating and cooling equipment perfectly to your building’s needs.

Manual D Duct Design

 Optimized airflow and duct layout for maximum performance.

Permit-Ready Documentation

 Our reports are built for approval—fast and frustration-free.

The Smarter Alternative to HVAC Load Calculation Software

Many of our clients come to us frustrated by clunky or confusing load calculation HVAC software. Whether they’ve struggled with CoolCalc or overwhelmed by doing Manual J calculations themselves, we offer a better option: expert-designed, permit-ready reports delivered fast. 

When you need more than just a calculator, you need a partner who understands HVAC design inside and out. 

Manual J Custom Design Services

Let's Design It Right. Together

If you’re ready to save time, cut red tape, and ensure your systems are built to perform, reach out today. We’ll help you get your Manual J, S, or D reports done right—the first time.