Welcome to the Wolff Mechanical Design Department

What is the Wolff Mechanical Design Department?  We are an exclusive department that focuses solely on engineering the HVAC systems for projects.  We utilize software to perform load calculations, equipment matching, duct designing, and ultimately a full set of mechanical plans for city inspectors or for installers to follow. We can also perform REScheck, LEED design and documentation, Green Build, etc…

Check city requirements hereCity HVAC Permit Requirements for New Construction

Our Services

Manual J

Manual S

Manual D

Manual T

Mechanical Plans to pass city inspectors (includes Manuals J/S/ and D)

VRF Designed Mechanical Plans

Light Commercial Mechanical Plans

REScheck/COMcheck or LEEDs documentation

*We use ACCA Manual J 8th Addition

Manual J


We perform a load calculation using the specs on the plan to get an accurate prognosis of the building.   Many HVAC contractors still use the rule of thumb of 400 square feet per ton.  Because of the incredible advancement of the building industry using this rule of thumb leads to oversized houses.  This leads to faster equipment failure, increased equipment cost, and most importantly an uncomfortable home.   Wolff Mechanical has been performing Manual J calculations for over 15 years and has a commanding understanding of Manual J load calculations.

Manual S


We perform a load calculation using the specs on the plan to get an accurate prognosis of the building.  After this is done we then select equipment that works with the load calculation to optimize comfort and energy efficiency.  This step is vitally important for home owner comfort.



Manual D

After Completing a Manual J load calculation and selecting the best equipment for the house based on the load we can now perform a duct design.  We always place and active return grill in every bedroom.





Manual T



Manual T goes hand in hand with a good duct design.  Manual T is focused on air distribution, register placement, return grill placement, types of registers and their sizes.  Performing an accurate manual T will also promote comfort by reducing too much or too little volume of air coming from a register which also influences the quietness.





Mechanical Plans

Wolff Mechanical designs full sets of mechanical plans.  This includes duct sizing, register sizing/CFM and schedule, equipment locations, thermostat location, ventilation and infiltration calculations.  Included also is all relevant code to be followed and diagrams.


VRF Designed Mechanical Plans

This service is for a project that is to be installed with a VRF system.  Wolff Mechanical has been and continues to be the leader in residential VRF designs.  We perform a detailed set of mechanical plans and have a close relationship with city inspectors that understand what we are doing.




Light Commercial Mechanical Plans


This service is for light commercial projects.  We perform a manual N as well as a mechanical plan for submittal to city inspectors.






Express Package

(all documentations and mechanical plan for a quick city approval)

This service is meant for those home owners, builders, or architects who need the right documentation and plans to pass city inspectors. Includes all documentation for city inspectors (Manual J/S/T/D documentation with full set of mechanical plans)

Complete Care Package

(Comprehensive and detailed set of mechanical plans)

This service is for those home owners, builders, or architects who want a detailed, easy to read, and field applicable set of mechanical plans.  Our goal here is to design the system so that very little to no changes in the field is needed.  (to do this service we require a full set of AutoCAD plans)

Contact Information

Email: Design Department, Amgad Rofail
Phone : 480-968-8208 Ext. (110)

HVAC Design Pricing Request Form

  • If you know how many systems you'd like, or where the ductwork will travel, etc., this is the place to mention it. Or, if you have a spec document, you can attach it below, along with your plans.