Every room gets the air it needs
Manual D duct design that the install crew can build.
Right-sized equipment still fails if the ducts starve the back bedroom. Manual D sizes every supply and return from the room loads and the blower you chose, then lays it out so your installers can follow it.
What it is
Manual D uses the room airflow from Manual J and the fan performance from Manual S to size trunks, branches, supplies and returns within the available static pressure.
We draw the layout on your plans and note the fitting and material assumptions, so the design and the install match.
When you need it
IRC Section M1601.1 requires duct systems to be sized in accordance with ACCA Manual D. On new construction and additions, many plan reviewers ask for the duct layout with the load calculation.
What we need from you
- Floor plans with the air handler location
- Your preferred duct material and system type
- Filter type and size, so its pressure drop is included
- Ceiling, attic or crawlspace constraints
What you receive
- Duct layout drawn on your plans
- Supply and return sizes with CFM per register
- Friction rate and static pressure worksheet
“I can't say enough good things about LoadCalcs.net. I am building an HVAC system and they helped design a ducting system that would ensure maximum efficiency for my equipment and my home. They have been there to answer any dumb question I've had.”
Questions
Can you design for rigid, flex or duct board?
Yes. Tell us what you plan to install before we start, including the filter. Material and filter both change the pressure budget, and we design to what you will actually build.
Do you design commercial ductwork?
Yes. Light-commercial duct design follows ACCA Manual Q. Ask for it with a Manual N.
Do I need Manual T as well?
Manual T selects and places the registers and grilles. It pairs naturally with Manual D when comfort and noise matter.
Same-day quotes
Drop the plans. Get a quote today.
Drop in the plan set and pick your services. A designer replies with price and turnaround, usually within 30 minutes during business hours.