What our HVAC load calculation service includes
Oversized HVAC equipment short-cycles, controls humidity poorly and costs more to buy and run; undersized equipment cannot keep the house comfortable on design days. A proper load calculation – based on the actual walls, windows, insulation, orientation, airtightness and local design temperatures – is how systems get sized correctly. Many US jurisdictions now ask for Manual J, S and D reports with the mechanical permit.
We model each room from your plans and specifications, apply the design conditions for your location, and produce heating and cooling loads per room and for the whole building. From there, Manual S matches equipment to the loads using manufacturer data, and Manual D sizes the duct system and airflow per room.
Once loads are approved, ducts and equipment can be drawn through HVAC drafting. In California, load calculations often go together with Title 24 compliance.
Deliverables you receive
- Room-by-room heating and cooling loads
- Whole-building load summary with design conditions
- Manual S equipment selection report (US)
- Manual D duct design and room airflow (US)
- Permit-ready PDF reports
- Commercial block loads on request
What we need from you
- Floor plans, elevations and sections
- Wall, roof, floor and window specifications
- Location and orientation
- Duct location and equipment preferences
Who orders this service
- HVAC contractors needing permit reports
- Home builders and energy raters
- Mechanical engineers needing calculation support
- Homeowners replacing systems
Software and file formats
Reports from Wrightsoft, Elite RHVAC or CoolCalc-style software (US), HAP/Trace-style block loads for commercial, CSA F280 calculations for Canada and spreadsheets to CIBSE and BS EN 12831 methods; all delivered as PDF.
HVAC Load Calculation Services standards in the USA, UK, Canada and Australia
We set up every project on the standard of the country where it will be built or manufactured. These are the references we work to most often:
| Country | Standards and codes we draft HVAC load calculation services to |
|---|---|
| USA | ACCA Manual J (8th edition), Manual S and Manual D; IRC M1401.3 and IECC requirements for sizing |
| UK | BS EN 12831 heat load calculation, CIBSE Guide A, MCS heat pump design requirements (MIS 3005-D) |
| Canada | CSA F280-12 residential heating and cooling capacity, NBC 2020 Part 9 requirements |
| Australia | AIRAH DA09 load estimation, NCC 2022 Section J for commercial, NatHERS context for residential |
Engineering responsibility: we prepare drawings, models and calculations as a drafting and design-support team. Where the law in your state, province or council requires it, the final design must be reviewed, signed and sealed by the licensed engineer or architect of record for the project. We work to their markups and do not stamp drawings ourselves.
How our HVAC load calculation services process works
- 1Send your files
Upload sketches, PDFs, markups, photos, scans or a model through the quote form. Tell us the standard (US, UK, Canada or Australia) and the deadline.
- 2Fixed quote in hours
We review the scope and reply with a fixed price, the deliverables list and a delivery date. Nothing starts until you approve it.
- 3Drafting & modeling
Your project is drawn in AutoCAD, Revit, Civil 3D, SolidWorks or the software you use, on your title block, layers and templates.
- 4QA check
A second drafter checks dimensions, annotations, layer standards, sheet numbering and cross-references against your input before anything is sent.
- 5Delivery & revisions
You receive native files plus PDFs. Comments come back as markups and we revise them quickly until the set matches the brief.
Turnaround and pricing
A residential Manual J/S/D package is typically delivered in 1–3 business days; commercial loads are quoted by building. Every job is priced as a fixed quote after we review your files, so you know the cost and the delivery date before work starts. See how our pricing works, or send your files through the quote form for a quick estimate.
Related services
HVAC Load Calculation Services projects often need HVAC drafting services, Title 24 compliance services and MEP drafting services as well. You can order them together on one quote, or browse every option in our MEP engineering services.
