HVAC News Guest Column
So your Manual J Load Calculation was just rejected
because it wasn’t “ACCA Certified” – What load calculation
software should you have used?
By: Tracy Savoy - Savoy Engineering Group
It is critical your Manual J
load analysis is produced with ACCA certified software by
someone who understands Manual J theory – not just someone
who can punch buttons in a software program. Ask your HVAC
designer if they have read the ACCA Manual J (8th Edition),
Manual S, Manual D & Manual T books and if they are
certified designers in the software they use.
ACCA (Air Conditioning Contractors of America) released its
Manual J load calculation procedure in 1986. ACCA wanted to
develop an accurate calculation method that not only saved
time but improved the quality of systems selected and duct
In 1985 at the Massachusetts Institute of Technology (MIT),
Bill Wright was giving a graduate seminar on heating,
ventilation, and air conditioning (HVAC) when he was
approached by the Air Conditioning Contractors of America (ACCA).
The largest organization of HVAC contractors in the United
States, the ACCA wanted to work with Wright to develop a
software program to run calculations for HVAC designers.
And, so, WrightSoft was born. Still the leader in HVAC
design software, it now produces many software programs to
aid in HVAC design. But its first product, a Manual J load
calculator, is still its flagship product. If you want to
calculate a load using Manual J, then it’s your best bet to
look for a qualified WrightSoft Manual J designer.
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This software program became known as Right-J, and it was
the beginning of a line of software programs that became
more advanced over time.
In order to become a WrightSoft Manual J designer,
candidates must undergo rigorous training. They must not
only learn how to use WrightSoft programs themselves, but
they must also learn how to clearly explain these programs
and their use to others. This is because it’s of vital
importance not only for the designer to understand his own
design, but also for the contractor to understand what the
design is intending to accomplish and why. That way, he’s
not just a robot following a plan, but a human being with
common sense who can recognize when something in the plan is
In addition, WrightSoft has WrightSoft University online
24/7 which we have every one of our designers go through
before beginning their first project with us. And the
WrightSoft technical staff is very easy to work with and
have solved every issue we have encountered quickly and
professionally. We have been producing ACCA compliant
WrightSoft HVAC designs since 2005 and have completed
thousands of projects with a 100% PASS rate!
ACCA Manual J Engineering Services – The Jack of All Trades vs.
When it comes to choosing ACCA Manual J engineering services,
you often have to choose between two prototypes: the jack of all
trades and the specialist. The jack of all trades offers a wide
variety of services, many of which you don’t really need. But
their list of services is often so long and impressive that
people don’t stop to consider whether or not the company does
any of those services particularly well. On the other hand, if
you look at a specialist, they may not be able to offer you much
more than what you need, but you do know that they’ve got to at
least be good at the few services they do offer you or else they
wouldn’t be able to survive. Contact them at