Our expertise · Building Performance & Engineering
Manual S Equipment Selection
Select equipment for the conditions it will actually serve, not for the tonnage on the label.
Nominal tonnage is a label, not a performance rating. What a piece of equipment actually delivers depends on the outdoor and indoor design conditions, the airflow it receives and how much of its capacity goes to removing moisture rather than lowering temperature, and those figures live in the manufacturer's expanded performance data, not on the nameplate. Manual S uses that data to match equipment to the calculated loads, so the system selected is the one the home needs at design conditions. Green Summit supports residential HVAC equipment selection using Manual S procedures within a defined design scope, connecting calculated loads and design conditions with manufacturer performance information and the project's documentation.
- Licensed engineering firm
- RESNET Rating Provider No. 1998-221
- Founded 2014
- Engineered substantiation, not estimates
Who this is for
Developers, builders and design teams, housing authorities, Tribal housing programs and HERS Raters who need documented equipment selections behind the systems their homes will run on.
What we do
- Review the inputs. Manual J results, design conditions, system type, the manufacturer's expanded performance data and the humidity-control needs establish the basis of the analysis, and we flag what is missing before we select.
- Calculate and coordinate. We prepare selection documentation that connects the loads to the manufacturer's performance data, and identify the inconsistencies that need a design-team decision.
- Control the revisions. When a material building or equipment change affects the result, we update the analysis and reissue it, so the selection on file describes the equipment being installed.
Our process
- Define the dwelling, the system and the output required. We settle the system type under consideration and what the deliverable has to support.
- Review the inputs and complete the project-specific calculation. We check the candidate equipment against the loads at the project's own design conditions, not at rated conditions.
- Resolve questions, issue the deliverable and identify any field-verification needs. The selection goes to the people who will design the ducts, order the equipment and pull the permit.
Benefits
- Documented assumptions instead of informal sizing rules.
- A clearer connection between the building design, the equipment and the airflow it needs.
- Information the team can use for permitting, contractor coordination and related certification work.
Why Green Summit
Green Summit is a consulting partner delivering end-to-end compliance solutions in building performance, specialty tax incentives and advisory services. Founded in 2014, we are a licensed engineering firm and RESNET Rating Provider No. 1998-221, and our modeling and field-verification experience keeps the selection connected to what will actually be installed. We select from the manufacturer's data at your conditions, never from a catalog label.
The local jurisdiction determines the submittal requirements and any required professional seal, and we tell you at the outset what your jurisdiction expects. Where the project also carries an energy-code pathway or a certification, the same team keeps the equipment selection consistent with the load calculation, the duct design and the field verification.
Frequently asked questions
What is Manual S equipment selection?
Manual S is the ACCA procedure for selecting residential heating and cooling equipment from the loads Manual J calculates. It compares the equipment's performance at the project's design conditions, taken from the manufacturer's expanded performance data, against the heating, cooling, airflow and humidity-control requirements, and documents why the selected model fits. It is the step that turns a load into a specific piece of equipment.
Is nominal tonnage enough to select equipment?
No. Selection uses the calculated loads, the design conditions and the manufacturer's performance information at those conditions. Nominal capacity does not describe how the equipment performs in your project's climate and at its airflow, so we never select from the label alone.
Can you evaluate variable-capacity heat pumps?
Yes. We apply the selection procedure and manufacturer data that fit the equipment type and review heating, cooling, airflow and humidity control together, because a system that satisfies one of those can still fall short on another.
Which records should we provide?
Manual J results, design conditions, system type, the manufacturer's expanded performance data and the humidity-control needs. We flag missing information and settle any assumptions with you before issuing the final analysis.
Can you coordinate this with the other Manual calculations?
Yes. Manual J establishes the loads, Manual S supports equipment selection and Manual D supports duct design. We scope them together so the inputs and decisions stay consistent, and the equipment you select is the equipment we design the ducts for.
Does the calculation guarantee comfort or code approval?
No. Installation, balancing, controls, how the home is actually used and the authority's review all matter. The calculation documents a defined design analysis, and we never present it as a promise about every aspect of installed performance.
Let's select equipment for the conditions it will serve.
Tell us the dwelling, where it is, the system type you are considering and whether a Manual J load calculation already exists.
Related solutions
- MEP, HVAC & Hot-Water Coordination
- Residential Energy-Code Compliance
- Energy Modeling
- Manual D Duct Design
- Building Systems Commissioning & Functional Verification
Program and technical references
ACCA: Manual S
Program information reviewed September 22, 2026. Current applicability, qualifications and program terms are confirmed for each engagement.
Or call 321-273-2200 · inquiry@greensummit.com