100+ Free PE Mechanical HVAC Practice Questions

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On a psychrometric chart, what does the dew-point temperature (DPT) represent for a given moist-air state point?

The dry-bulb temperature at which the air is saturated at that humidity ratio

The wet-bulb temperature read along the saturation line

The dry-bulb temperature at 50% relative humidity

The dry-bulb temperature on the constant-enthalpy line

to track

2026 Statistics

Key Facts: PE Mechanical HVAC Exam

Exam Questions

NCEES

8 hrs

Test Time

NCEES

9 hrs

Total Appointment

NCEES

$400

NCEES Fee

NCEES

700

GWP Cap (Jan 1 2026)

EPA AIM Act

Year-round

CBT Window

Pearson VUE

PE Mechanical: HVAC and Refrigeration is one of three NCEES PE Mechanical sub-disciplines. The 80-question CBT runs 8 hours of test time inside a 9-hour appointment, with a 50-minute scheduled break. NCEES provides the PE Mechanical Reference Handbook as a searchable PDF — psychrometric chart, refrigerant property tables, and ASHRAE excerpts. The 2026 exam leans heavily on the AIM Act low-GWP refrigerant transition (R-32, R-454B replacing R-410A), ASHRAE 90.1-2022 efficiency tables, and ASHRAE 62.1-2022 ventilation rate procedure. The $400 NCEES fee covers one attempt; state board fees are separate.

Sample PE Mechanical HVAC Practice Questions

Try these sample questions to test your PE Mechanical HVAC exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1On a psychrometric chart, what does the dew-point temperature (DPT) represent for a given moist-air state point?

A.The dry-bulb temperature at which the air is saturated at that humidity ratio

B.The wet-bulb temperature read along the saturation line

C.The dry-bulb temperature at 50% relative humidity

D.The dry-bulb temperature on the constant-enthalpy line

Explanation: Dew-point is the dry-bulb temperature reached if the air is cooled at constant humidity ratio until it becomes saturated (RH = 100%). On a psychrometric chart you slide horizontally (W constant) from the state point left to the saturation curve and read DBT.

2Air at 75°F DBT and 50% RH has a humidity ratio of approximately 0.00925 lb_w/lb_da and an enthalpy of about 28.1 BTU/lb_da. If this air is sensibly heated to 95°F (no moisture added), what happens to the relative humidity?

A.RH increases because enthalpy rose

B.RH stays the same because humidity ratio is unchanged

C.RH decreases because saturation pressure rose while vapor pressure stayed the same

D.RH drops to zero because the air is heated

Explanation: Sensible heating moves the state point horizontally to the right at constant W. The partial vapor pressure stays put, but saturation pressure increases sharply with temperature, so RH = p_v/p_sat falls. At 95°F with W = 0.00925, RH drops to roughly 27%.

3A space requires 20,000 BTU/h of sensible cooling and 5,000 BTU/h of latent cooling. What is the sensible heat ratio (SHR) of the space load?

A.0.20

B.0.25

C.0.75

D.0.80

Explanation: SHR = q_sensible / q_total = 20,000 / (20,000 + 5,000) = 20,000 / 25,000 = 0.80. The cooling coil must operate along a process line on the psychrometric chart that matches this SHR to meet the space condition.

4Outdoor air at 95°F DBT and W = 0.018 lb_w/lb_da is mixed with return air at 75°F DBT and W = 0.010 lb_w/lb_da in the ratio 25% OA / 75% RA by mass. What is the mixed-air dry-bulb temperature?

A.77°F

B.80°F

C.82°F

D.85°F

Explanation: Mixed-air DBT is mass-weighted: T_mix = 0.25(95) + 0.75(75) = 23.75 + 56.25 = 80.0°F. The same weighting applies to humidity ratio: W_mix = 0.25(0.018) + 0.75(0.010) = 0.012 lb_w/lb_da.

5A cooling coil has an entering condition of 80°F DBT / 67°F WBT and a leaving condition of 55°F DBT / 54°F WBT. The apparatus dew-point (ADP) is 50°F. What is the coil bypass factor (BF)?

A.0.10

B.0.17

C.0.25

D.0.33

Explanation: Bypass factor BF = (T_lvg − T_adp) / (T_ent − T_adp) = (55 − 50) / (80 − 50) = 5 / 30 = 0.167. BF represents the fraction of air that effectively bypasses the coil unconditioned; (1 − BF) is the contact factor.

6Per ASHRAE 62.1-2022 Ventilation Rate Procedure, the breathing-zone outdoor airflow Vbz is computed as:

A.Vbz = Rp × Pz

B.Vbz = Ra × Az

C.Vbz = Rp × Pz + Ra × Az

D.Vbz = (Rp + Ra) × (Pz + Az)

Explanation: ASHRAE 62.1 separates ventilation into a people component (Rp × number of people Pz) and an area component (Ra × floor area Az), then sums them. Zone outdoor airflow Voz is then Vbz divided by zone air distribution effectiveness Ez.

7An office zone has 25 occupants and 2,500 ft². Per ASHRAE 62.1-2022, Rp = 5 cfm/person and Ra = 0.06 cfm/ft² for offices. What is the breathing-zone outdoor airflow Vbz?

A.125 cfm

B.150 cfm

C.275 cfm

D.400 cfm

Explanation: Vbz = Rp·Pz + Ra·Az = (5)(25) + (0.06)(2,500) = 125 + 150 = 275 cfm. Voz, the actual zone outdoor airflow delivered, equals Vbz/Ez; for a typical ceiling-supply cooling system Ez = 1.0 so Voz also = 275 cfm.

8Under standard sea-level air conditions, the sensible heat factor for cfm-based load calculations is approximately 1.08. What does this constant represent?

A.The conversion from BTU/h to ton of refrigeration

B.The product of air density and specific heat times 60 min/h ≈ 0.075 × 0.24 × 60

C.The ratio of sensible to latent heat in standard air

D.The bypass factor for a typical cooling coil

Explanation: q_sensible (BTU/h) = 1.08 × cfm × ΔT comes from ρ·cp·60 = 0.075 lb/ft³ × 0.24 BTU/lb·°F × 60 min/h = 1.08. At higher altitudes ρ decreases and the constant must be reduced (often to about 1.0 at 5,000 ft).

9An air-handling unit delivers 4,000 cfm of supply air at 55°F to a space maintained at 75°F. Assuming sea-level standard air, what is the sensible cooling capacity (BTU/h)?

A.43,200 BTU/h

B.64,800 BTU/h

C.86,400 BTU/h

D.108,000 BTU/h

Explanation: q_s = 1.08 × cfm × ΔT = 1.08 × 4,000 × (75 − 55) = 1.08 × 4,000 × 20 = 86,400 BTU/h, which equals 86,400/12,000 = 7.2 tons of refrigeration if all sensible.

101 ton of refrigeration is defined as the rate of heat removal equivalent to:

A.3,412 BTU/h (1 kW)

B.12,000 BTU/h (3.517 kW)

C.25,000 BTU/h

D.33,475 BTU/h (boiler horsepower)

Explanation: 1 ton of refrigeration = the heat absorbed by melting 2,000 lb of ice in 24 hours = 12,000 BTU/h = 3.517 kW. This is a memorize-cold conversion appearing throughout HVAC sizing problems.

About the PE Mechanical HVAC Exam

The NCEES PE Mechanical: HVAC and Refrigeration exam is an 80-question computer-based test for mechanical engineers practicing in HVAC, refrigeration, and building systems. The exam covers Principles (basic engineering practice, thermodynamics, psychrometrics, heat transfer, fluid mechanics, energy/mass balances) and Applications (heating and cooling loads, equipment and components, systems and components — air-side, water-side, and refrigeration). Candidates must apply ASHRAE 62.1 (ventilation), ASHRAE 90.1 (energy), ASHRAE 55 (thermal comfort), ASHRAE 15 (refrigerant safety), the IECC, and the IMC, plus AIM Act refrigerant rules.

Questions

80 scored questions

Time Limit

8 hours (9-hour appointment)

Passing Score

Approximately 70% (scaled — NCEES sets the cut score per form)

Exam Fee

$400 (NCEES (Pearson VUE))

PE Mechanical HVAC Exam Content Outline

~35%

Principles

Basic engineering practice, thermodynamics fundamentals, psychrometrics (DBT, WBT, DPT, RH, humidity ratio, enthalpy), heat transfer (conduction, convection, radiation, LMTD, ε-NTU), fluid mechanics, energy and mass balances

~20%

Applications: Heating & Cooling Loads

Sensible and latent loads, sensible heat ratio, ventilation loads, infiltration, mixed-air state, ASHRAE 62.1 ventilation rate procedure, CLTD/RTS, Manual J residential loads, energy recovery

~25%

Applications: Equipment & Components

Vapor-compression refrigeration (COP, EER, SEER, ton), absorption cycles, chillers (Path A/B IPLV per ASHRAE 90.1), boilers, pumps (NPSH, affinity laws), fans (affinity, fan curves), cooling towers (range, approach), heat exchangers

~15%

Applications: Systems & Components

Air-side: ducts (equal-friction, static-regain), AHU components, VAV systems, filters. Water-side: chilled-water and hot-water distribution, pump piping. Refrigeration: vapor-compression vs absorption, refrigerant selection under the AIM Act

~5%

Codes, Standards & Supportive Knowledge

ASHRAE 62.1-2022 (ventilation), ASHRAE 90.1-2022 (energy), ASHRAE 55-2023 (thermal comfort), ASHRAE 15 (refrigerant safety classification A1/A2L/A3), IECC 2024 cycle, IMC, engineering economics, NSPE professional ethics

How to Pass the PE Mechanical HVAC Exam

What You Need to Know

Passing score: Approximately 70% (scaled — NCEES sets the cut score per form)
Exam length: 80 questions
Time limit: 8 hours (9-hour appointment)
Exam fee: $400

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

PE Mechanical HVAC Study Tips from Top Performers

1Master psychrometric chart reading cold — given any two properties, locate the state point and read DBT, WBT, DPT, RH, W, and h within seconds

2Memorize the ventilation rate procedure: Vbz = Rp × Pz + Ra × Az, then divide by zone air distribution effectiveness Ez and ventilation efficiency Ev

3Drill the vapor-compression COP shortcut: COP_cooling = h_evap_out − h_evap_in divided by compressor work; convert to EER by multiplying by 3.412

4Know fan and pump affinity laws: flow ∝ N, pressure ∝ N², power ∝ N³ — and that they apply only at constant impeller diameter and density

5Practice mixed-air state: T_mix = (m_oa·T_oa + m_ra·T_ra) / m_total, with W and h computed the same mass-weighted way

6Memorize 1 ton of refrigeration = 12,000 BTU/h = 3.517 kW; sensible heat factor q_s = 1.08 × cfm × ΔT (sea level, IP units)

7For the AIM Act: GWP cap 700 for new residential/light-commercial AC from 1/1/2026; R-32 (675) and R-454B (466) are compliant A2L refrigerants under ASHRAE 15

8Cooling tower: range = T_cw_in − T_cw_out, approach = T_cw_out − T_wb_ambient — approach drives tower size, not range

9ASHRAE 90.1-2022 chillers: Path A optimizes full-load EER, Path B optimizes IPLV; you must meet both numbers in the chosen path

10Practice unit conversions in both directions — exam mixes IP and SI within the same problem; the NCEES handbook conversion table is bookmark-worthy

Frequently Asked Questions

How is PE Mechanical: HVAC and Refrigeration different from the other two PE Mechanical sub-disciplines?

NCEES splits PE Mechanical into three 80-question discipline exams: HVAC and Refrigeration, Machine Design and Materials, and Thermal and Fluid Systems. You select one at registration. HVAC focuses on psychrometrics, building loads, refrigeration cycles, ASHRAE 62.1/90.1/55/15, and air- and water-side equipment — the daily work of a mechanical engineer designing buildings or refrigeration systems.

What is the 2026 exam format and fee?

The exam is 80 multiple-choice questions delivered as a year-round computer-based test at Pearson VUE. The appointment is 9 hours total (2-minute NDA, 8-minute tutorial, 8 hours of exam time, and a 50-minute scheduled break). The NCEES exam fee is $400; state board application fees are separate. NCEES does not publish a fixed passing percentage — scoring is scaled and the cut score is set per form.

Which references can I use during the exam?

The exam is closed-book except for the NCEES PE Mechanical Reference Handbook, supplied on screen as a searchable PDF. The handbook includes the psychrometric chart, refrigerant property tables (R-134a, R-410A, R-32, ammonia), Moody diagram, conversion factors, and condensed ASHRAE excerpts. Practice with the official handbook PDF before exam day — searching for tables under time pressure is itself a tested skill.

How does the AIM Act change what 2026 candidates need to know?

The EPA's Technology Transitions Rule under the AIM Act caps GWP at 700 for new residential and light commercial AC and heat pumps installed on or after January 1, 2026, effectively retiring R-410A (GWP ≈ 2088) for new equipment. Compliant refrigerants include R-32 (GWP 675) and R-454B (GWP 466), both A2L (mildly flammable) under ASHRAE 15. Expect questions on refrigerant safety classification, charge limits, and selection criteria.

What ASHRAE standard editions does the 2026 exam reference?

NCEES does not lock to a single edition, but practice should align with current standards: ASHRAE 62.1-2022 for ventilation rate procedure (Vbz = Rp·Pz + Ra·Az), ASHRAE 90.1-2022 for minimum equipment efficiency (Path A/B IPLV for chillers), ASHRAE 55-2023 for thermal comfort (PMV/PPD, comfort zone), and ASHRAE 15 for refrigerant safety. The IECC 2024 cycle and IMC also appear in code questions.

How should I structure HVAC-specific study time?

Plan 200-300 hours over 3-6 months. Spend roughly one-third on psychrometrics (chart reading, mixed-air, coil processes, SHR), one-third on equipment (chillers, fans, pumps, cooling towers, refrigeration cycle calcs), and one-third on systems and codes (ASHRAE 62.1/90.1/15, duct sizing, hydronic systems). Solve every problem from the NCEES sample exam at least twice using the on-screen handbook to build search speed.