The HVAC Installation Process, Step by Step

The Ten Steps

1. Step 1

   Initial evaluation

   The existing system, comfort complaints, duct condition, access and how the home is used are reviewed. Some homes leave this step with a repair or correction rather than a replacement plan.

2. Step 2

   Load calculation and design when replacement proceeds

   Heating and cooling loads are calculated for the home, with the sensible and latent split, using inputs collected from the building rather than the existing tonnage.

3. Step 3

   Manual S equipment selection

   Candidate equipment is compared against the calculated loads and local design conditions using manufacturer performance data, and indoor and outdoor components are confirmed as an approved combination.

4. Step 4

   Duct and airflow evaluation

   The distribution system is evaluated against the airflow the selected equipment needs, including return capacity, transitions, filtration and any Manual D or Manual T considerations.

5. Step 5

   Written scope and homeowner approval

   You receive a written scope covering equipment, duct work, electrical, refrigerant lines, drainage, controls, commissioning, warranty terms and what is excluded. Nothing is ordered before you approve it.

6. Step 6

   Permits and scheduling where required

   Permit and inspection requirements are set by the local jurisdiction and depend on the work performed. Where they apply, they are handled before installation is scheduled.

7. Step 7

   Equipment removal and installation

   Old equipment is removed and disposed of, the new equipment is set, leveled and supported, and plenums, transitions and connections are made and sealed with service clearances preserved.

8. Step 8

   Electrical, refrigerant, drainage and controls

   Disconnects and circuits are completed, refrigerant lines are routed and the system evacuated and charged per manufacturer instructions, drainage and safety switches are installed, and controls are configured for the installed equipment.

9. Step 9

   Startup and commissioning

   The system is started and readings are taken and compared with the manufacturer's published specifications for that equipment. Readings outside expectation are investigated before the job is called complete.

10. Step 10

    Documentation, walkthrough and warranty

    You receive the written scope, equipment models and serial numbers, startup readings, control settings and warranty registration, plus a walkthrough of operation, filters and maintenance.

What Belongs to Design, and What Belongs to the $89 Comfort Audit™

1–2 hour appointment • Written findings • $89 credited toward approved work. The audit measures static pressure, temperature split and relative humidity, inspects accessible components, and documents findings with prioritized recommendations.

Steps 2, 3, 4 and 9 above — formal load calculation, Manual S equipment selection, Manual D duct design and complete installation commissioning — are not included in the $89 appointment. They are part of a replacement project, or quoted separately when the findings show they are needed. Formal load calculations, detailed duct design and advanced testing may be recommended separately when the initial findings show they are needed.

What You Should Have at the End

• The written scope you approved, including anything added during the work.
• Equipment model and serial numbers for the indoor and outdoor components.
• The startup readings taken at commissioning.
• Control settings as configured, including staging and any humidity features.
• Warranty registration confirmation and the terms that apply.
• Filter type and size, and the maintenance the system needs.

For the details that most often go wrong along the way, see the installation mistakes guide, and for what each line of the scope costs, see the installation cost guide.

Frequently Asked Questions

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