Looking for a fully-licensed, insured and certified firm to tackle your load calculations for you? Need someone who listens and understands your need? Get thorough and quality results with HeatLoad USA. We offer professional and reliable design services for a wide variety of residential and commercial needs, working with the dedication and craftsmanship that has earned us a reputation for excellence.

​​Manual D is essentially a sizing exercise for residential ductwork.  Ductwork must be sized appropriately in order for the whole house to be able to be heated and cooled properly. 

The size of the home,  zip code, elevation, summer high & winter low temperatures, exposure to southern and western sun, room function, amount of windows, square feet of a room, which floor it is on and summer humidity levels  -  all play a function in determining the size and amount of ducts needed for a room.

Sizing equipment, selecting the equipment and then sizing the ducts are all integral parts of a good HVAC design. 

For a competent HVAC design, we go that extra step.  We design our system for what we call “occupant transparency”.  That is the end user/customer should not hear or feel the HVAC system. They should not even know it's on. A properly designed system will keep all the rooms very close to the same temperature and save money. 

A good and well done Manual D is an key component to achieving homeowner comfort, safety, and efficiency.  Our Manual D designs provide you the following:

  • Load calculations for each room

  • CFM (volume of air) needed for each room

  • Size of furnace, heat pump, AC required to satisfy the home

  • Equipment Part numbers for: Furnace, Condenser, Coils and/or heat pump

  • Location of central heating/cooling equipment

  • Full duct layout showing each individual trunk, branch, register, vent and all ducts for each zone

  • Short and Long J1 Forms

  •  Summary load forms

  • List of trunks and branches showing length and materials needed

  • Plus more…..

Optional: Complete inventory list needed to purchase materials for the job. This is particularly useful for homeowners and DIYers

Next Steps: Call or TEXT us:  973-544-6800


Why Choose Heat Load USA?

We have your back.  If you are a contractor, architect, engineer or builder, we know you have deadlines and customers waiting.  Count on us for timely and accurate reports that you can print out and take to your building department. 

We are certified.  ACCA created and sets the standards for Manual J, D & S. These standards are now adopted into the national mechanical codes. We are certified by ACCA on Manual J, Manual D and Manual S. Only use a design professional licensed and certified by ACCA for best results. 

We are also HVAC contractors.  Make sure the person doing your load calculations has live install experience, and is certified. Many have read about load calculation.  Hiring a certified professional with actual install experiences takes you to the next level.

100% Approval Rate.  All of our Manual J, D & S work is guaranteed to pass local township ACCA-heat load related requirements, all over the US. Weather you are in Maine, Virginia Florida or California.  You must provide us the drawings and comply with other regulatory requirements.  We serve all of the USA. We can help you. 

NEXT DAY SERVICE: Our Standard turnaround 4-business days.  Next Day Service is available (for all orders received by 4:00pm Eastern Standard Time)

We are here to serve you, so feel free to call/text us any time:  

  Ready to place your order?  Call or TEXT us: 973-544-6800        



What Do We Need In Order To Prepare Your Manual D?

  • Floor Plan for each floor (including basement if applicable)
  • Sq ft of Windows on each side, on each floor
  • Sq Ft of doors on each side, on each floor
  • How you want your ducts laid out - Ideally your rough sketch of the ducts
  • Address of property 
  • Any known insulation levels in the home
  • Location of equipment and ductwork  - Basement, Conditioned space, Attic Garage etc.  
  • If more then one system, we need to know the coverage area and location of each system
  • Email all these to info@HeatLoadUSA.com.  

We will respond right away, and review what you sent us. If we are good, we will send you an invoice via PayPal. Pay that invoice and we will deliver your report within 48 hours. ​

Call/Text Us:   973-544-6800

Email:  Info@HeatLoadUSA.com


* HVAC Design  * Manual D

*Duct Layout & Sizing

Professionally Prepared For You

Valid in All States in The US

Yes serve ALL of the USA including

Texas, Colorado, Virginia, California and NY/NJ/MD

Call/Text US Now:  973-544-6800    or email us:  info@HeatLoadUSA.com

  • ​​Manual D
  • Manual D Calculation
  • Manual J & D Calculations

Heat-Load USA

ACCA Manual J load calculation - Manual S - Manual J HVAC - Manual J Calculation Service - Heat Load Calculation - Residential Load Calculation - Manual J Services - What is a Manual J - manual j hvac residential load calculation

- load calculation - Manual N - Commercial load calculation = HVAC ENGINEERS - HVAC CONSULTANTS

- ACCA Manual N Commercial load calculation - Manual D - Manual D calculation - Manual J & D Calculations