HVAC Permit Plans & Manual J, S, D for Your Home
We prepare Manual J, S and D calculations for single-family homes, townhomes and small multifamily units using ACCA-based methods that reviewers and contractors recognize.
What we provide
Our work follows ACCA standards, so your submittal looks familiar to building departments and HVAC contractors and is easier to review. You receive permit-ready reports and duct layouts your contractor can build from directly.
When you need this
New construction or additions, equipment replacements with size changes, city requests for Manual J / Manual D, or energy-code driven compliance.
What you get
Manual J room-by-room heating and cooling loads, Manual S equipment selection basis, Manual D duct design when purchased, and PDF files ready for permit upload.
What you get
Share floor plans and construction details, we run the calculations and review the results, then deliver permit-ready documents. Typical turnaround is 2-3 business days.
Rule-of-thumb sizing is faster but often oversizes the system, which can create comfort issues and wasted energy. Many modern codes and jurisdictions now expect Manual J-based design instead.
What Our Clients Say
Real feedback from homeowners, contractors, and architects across the US.
Why accurate HVAC calculations matter
Guesswork in HVAC sizing leads to permit rejections, poor airflow, and moisture issues. By trusting our specialized MEP team for your Manual J, S, and D calculations, you guarantee code-compliant equipment sizing and well-engineered ductwork that passes city inspections instantly.
Frequently Asked Questions
Do I need a Manual J calculation before purchasing a new HVAC system for my home?
Yes, absolutely. Buying equipment without a Manual J report usually leads to guessing, which results in an oversized system that turns on and off constantly (short-cycling) and fails prematurely. A precise Manual J calculation ensures you buy the exact equipment size needed for your home’s insulation and layout in the United States.
Do I need to submit Manual J, S, and D reports before starting construction or applying for a building permit?
Yes. Most local building departments across the United States require approved Manual J (load calculations), Manual S (equipment selection), and Manual D (duct design) reports as part of your mechanical permit plans before any construction begins or permits are issued.
Can I order just a Manual J and S, or do I absolutely need a Manual D duct layout plan too?
While Manual J and S size the equipment, Manual D outlines how to distribute that air properly. Many United States jurisdictions require all three components for plan approval. Even if your city does not strictly demand it, a Manual D duct layout ensures balanced airflow and eliminates hot or cold spots in your home.
What happens to my HVAC calculations if I change my house window sizes or insulation types during the build?
Any changes to the building envelope (windows, insulation, framing) alter the heating and cooling loads. If you make modifications during construction, your Manual J and S must be updated and re-submitted to the building department to avoid inspection failures in the United States.
Do I need a full Manual J and S calculation if I am just replacing an existing HVAC unit?
Code requirements vary by city, but if you have made energy-efficiency upgrades (like new windows or better insulation) since the original system was installed, your home will need a smaller unit. A new Manual J ensures you do not waste money buying an inefficiently large replacement system.