PE Mechanical HVAC and Refrigeration Exam Prep

The HVAC and Refrigeration exam applies thermodynamics, heat transfer, and fluid mechanics to buildings and equipment. In a real air-handling system these subjects are tied together. The cooling load and supply air condition set the airflow, the airflow sets the duct losses, and the duct losses set the fan. It is common to know your own corner of the field well and feel rusty elsewhere. STEM Tutor 360 builds one-on-one prep around that pattern, with a diagnostic first and a plan worked backward from your exam date. The tutor is a Georgia Tech mechanical engineer.

We teach the reasoning behind each calculation as well as the formula. Why does the sensible heat ratio matter on the chart? What fixes the refrigerant state at the compressor inlet? Which method fits which duct problem? Once the reasoning is clear, the numbers go faster and unit traps are easier to spot. Codes and standards are covered at a general level: what each one is for, how it is organized, and how to read it quickly.

How we build your plan

• A timed diagnostic samples every major topic, so the plan follows your gaps and not a generic syllabus.
• The thermodynamic core comes first: psychrometric processes, refrigeration cycles, and property lookups.
• The air side is next (loads, ventilation, ducts, fans, system curves), then the water side (hydronics, pumps, equipment).
• Every problem is worked with the handbook open on screen, and every miss goes in an error log sorted by cause: concept, lookup, units, or arithmetic.
• The final weeks are mixed timed sets at exam pace, plus full-length practice if your schedule allows.

A sample problem, worked

A zone needs 30,000 Btu/h of sensible cooling. Room air is held at 75°F and supply air arrives at 55°F. What supply airflow does it need?

For standard air, sensible heat is $Q = 1.08 \times \text{CFM} \times \Delta T$. The 1.08 is a unit conversion: $0.075\ \text{lb/ft}^{3} \times 60\ \text{min/h} \times 0.24\ \text{Btu/lb-}^\circ\text{F}$. $\Delta T$ is 20°F, so $$\text{CFM} = \dfrac{30{,}000}{1.08 \times 20} = 1{,}389$$

Then ask what changes. At altitude or with hot air the density is lower, so the same load needs more airflow. Knowing where the 1.08 comes from lets you correct it when conditions are not standard.

About the exam

HVAC and Refrigeration is one of three separate NCEES PE Mechanical exams, along with Machine Design and Materials and Thermal and Fluid Systems. It is computer-based and offered year-round at Pearson VUE test centers. It has 80 questions and about 8 hours of exam time, inside a 9-hour appointment that includes a tutorial and a scheduled break.

The NCEES PE Mechanical Reference Handbook is provided on screen. Eight hours for 80 questions averages about 6 minutes a question, so we practice at that pace. Check the current NCEES exam specification for the topic list and question weights. STEM Tutor 360 is an independent tutor and is not affiliated with NCEES.