Energy calculations and Manual J, S, and D
Our Manual J calculation services use your plans, local climate, and building details to prepare HVAC load calculations for your home.
Calculate the loads before choosing the system
Manual J estimates a home's heating and cooling loads. Manual S guides equipment selection for those loads. Manual D covers the duct layout and sizing. Oxalis uses your plans and project inputs to prepare the calculations included in your scope.
Who we work with
- Homeowners and builders
- HVAC contractors
- Architects and designers
- Permit applicants
What your team receives
- Manual J load calculation
- Manual S equipment selection
- Manual D duct design when included
- Energy and permit documentation
- Revision support when project inputs change
From project plans to calculation documents
- Gather plans, building orientation, enclosure details, window specifications, and system information.
- Resolve missing or conflicting project information.
- Calculate loads using the project's design inputs.
- Select equipment and design ductwork as included in the scope.
- Deliver the documents for review and handle included revisions.
Common questions
What is the difference between Manual J, S, and D?
Manual J calculates room and whole building loads. Manual S matches equipment to those loads. Manual D guides the design of the duct distribution system.
Does a Manual J request schedule an inspection?
No. Manual J, S, and D requests are document review work. They do not automatically create an inspection, calendar event, or field route. Request any field work separately.
How quickly can calculations be completed?
Timing depends on the project's complexity and the information available. Send complete plans and system details so the team can confirm the scope and schedule.
Let’s make the next step clear.
Tell us what you’re building, where it is located, and which certification requirements you are working through.