ACCA Manual J • Building-science HVAC design

Load Calculations (Manual J) for accurate, code-aligned system design

Manual J is the foundation for right-sized HVAC. Movement Energy Inc calculates room-by-room heating and cooling loads using California-relevant inputs—so your equipment selection, duct design, and Title 24 documentation are built on real data, not rules of thumb.

Engineer reviewing building plans for HVAC load calculations
What we deliver

A Manual J report you can build from

We produce clear, defensible load calculations that support equipment sizing (Manual S), duct design (Manual D), and energy compliance workflows.

Room-by-room heating & cooling loads

Detailed sensible/latent loads by zone to avoid hot/cold rooms and oversizing.


California-relevant inputs & assumptions

Orientation, glazing, shading, insulation, infiltration, internal gains, and ventilation aligned to the project scope.


Design conditions & documentation

Clear design temperatures, notes, and deliverables that installers, designers, and HERS/Title 24 teams can reference.


Heat pump–ready sizing foundation

Loads that support modern electrification strategies and comfort-first system selection.

Why Manual J matters (and what it prevents)

HVAC technician documenting measurements in a home

Right-sized equipment

Avoid short-cycling, humidity issues, and unnecessary upfront cost from oversizing.

Better comfort in every room

Room-by-room loads inform airflow targets and zoning decisions—reducing hot/cold spots.

Stronger compliance & fewer surprises

Documented assumptions and loads help support Title 24-related workflows and change-order control.

Our process

How we build a defensible Manual J

We combine field verification (when applicable) with building-science inputs to produce loads you can trust.

1) Project intake & scope alignment

We confirm building type, conditioning goals, zoning, ventilation approach, and any compliance requirements.

2) Data collection

Plans and/or site data: floor areas, ceiling heights, envelope assemblies, windows/doors, shading, orientation, and duct location.

3) Modeling & load calculations

Room-by-room heating/cooling loads with transparent assumptions and design conditions appropriate for the project.

4) Deliverables & next-step recommendations

We provide the Manual J output and guidance for Manual S equipment selection and Manual D duct design (as needed).

FAQ

Manual J questions, answered

Not sure where to start? Here are the most common questions we get from homeowners, contractors, and project teams.

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