Cheat sheet
AEE Certified Energy Manager (CEM) Cheat Sheet
Cheat sheet AEE Certified Energy Manager (CEM) Cheat Sheet Practice Questions Study Guide Print / Save PDF
Policies, Codes & Standards 6-8% of exam Codes & Standards GHG Scopes ISO 50001 Green Building Ratings
Rates, Tariffs & Supply 5-7% of exam Rate & Tariff Terms Demand Charge vs Energy Charge Ratchet Clause Power Factor Penalty
Audits & Instrumentation 7-11% of exam Audit Levels & Metrics HHV vs LHV ASHRAE Levels 1-3 Infrared Camera
Accounting & Economics 6-10% of exam Economic Analysis Terms Simple Payback vs NPV IRR Escalation Rate
Electrical Systems & Motors 7-11% of exam Power & Motor Terms Affinity Laws Power Factor Correction Motor Loading
Lighting Systems 5-7% of exam Lighting Metrics Lumens vs Footcandles Luminous Efficacy Color Rendering Index
HVAC & Building Envelope 10-16% of exam HVAC Efficiency Metrics COP vs EER vs kW/ton R-value vs U-value Degree Days
Automation & Controls 6-10% of exam Controls & Automation Terms Setback vs Reset Control P vs PI vs PID Fault Detection
Energy Storage Systems 3-5% of exam Energy Storage Terms Full Storage vs Partial Storage Round-Trip Efficiency Ice & PCM Storage
Boiler & Steam Systems 4-6% of exam Boiler & Steam Terms Steam Trap Failure Boiler Blowdown HHV vs LHV Fuel
Distributed Generation & Renewables 4-6% of exam Distributed Generation Terms CHP Fuel Utilization Capacity Factor Net Metering
Industrial Systems 6-8% of exam Industrial Systems Terms Compressed Air Costs Throttling vs VFD Cooling Tower Approach
Operations, Maintenance & Commissioning 7-11% of exam O&M & Commissioning Terms Preventive vs Predictive Maintenance Commissioning vs Retrocommissioning Persistence of Savings
ESPC & Measurement & Verification 3-5% of exam ESPC & M&V Terms Guaranteed vs Shared Savings ESPC IPMVP Options A-D M&V Boundary
Quick Facts Exam CEM Credential Certified Energy Manager Questions 130 (120 scored, 10 trial) Time 4 hours Format Open-book, open-note, calculator required Pass 700 points (scale unpublished) Retake wait 60 days between attempts Renewal 3-year cycle, CE credits BoK version v1.8 (Jun 19, 2026) Handbook version v2.15 (Jul 1, 2026)
Codes & Standards PO ASHRAE 90.1 Baseline commercial building code ASHRAE 62.1 Indoor air ventilation rate ASHRAE 55 Thermal comfort conditions standard Guideline 14 M&V measurement uncertainty guidance ISO 50001 Energy management system standard ENERGY STAR EPA energy benchmarking rating
Demand Charge vs Energy Charge TA
Demand charge Bills peak kW pulled Utility sizes for that peak
Energy charge Bills total kWh used Scales with consumption, not peak Peak power vs total energy
Rate & Tariff Terms TA Demand charge Bills peak kW pulled Energy charge Bills total kWh used Ratchet clause Prior peak sets minimum Load factor Average demand over peak Power factor penalty Surcharge below utility threshold Time-of-use rate Price varies by hour
Btu Unit Conversions AU 1 kWh = 3412 Btu | 1 therm = 100000 Btu 1 kWh = 3412 Btu 1 therm = 100000 Btu EUI uses kBtu per sq ft Convert fuels to one basis
HHV vs LHV AU
HHV Includes water vapor condensation heat Always the higher value
LHV Excludes water vapor heat Equal if no hydrogen, no moisture Include vs exclude vapor heat
Audit Levels & Metrics AU ASHRAE Level 1 Walk-through, low-cost recommendations ASHRAE Level 2 Detailed engineering survey calcs ASHRAE Level 3 Investment-grade financing-ready audit Energy Use Index kBtu per square foot Energy Cost Index Dollars per square foot Infrared camera Finds hot spots, leaks
Audit Levels AU L1 Walkthrough → L2 Survey → L3 Investment-grade L1: quick, low-cost review L2: engineering survey, calcs L3: financing-ready, detailed data All levels feed the ECM list
Simple Payback vs NPV EC
Simple payback Cost over annual savings Ignores time value of money
NPV Discounts all future cash flows Shows value beyond required return Quick screen vs value method
Economic Method Picker EC Need years to repay → Simple payback Compare dollar value created → NPV Check return vs hurdle rate → IRR Rank different-size projects → NPV, not IRR Include future price increases → Escalation rate Need present-value ratio screen → SIR
Economic Analysis Terms EC Simple payback Cost over annual savings NPV Discounted cash flows minus cost IRR Discount rate where NPV zero Discount rate Time value of money Escalation rate Annual energy price increase SIR PV savings over PV cost
Power Factor Correction EL kVAR = kW × (tanθ1 − tanθ2) Example: PF 0.80 → 0.95 Example: 500kW needs ≈211 kVAR Real power kW stays same Apparent power kVA drops
Power & Motor Terms EL Power factor Real power over apparent Real power (P) Does useful work, kW Reactive power (Q) Sustains magnetic fields, kVAR Apparent power (S) Vector sum of P, Q Affinity laws Flow, head, power vs speed Motor loading Actual over rated output kVAR sizing kW × (tanθ1 − tanθ2)
Lighting Metrics LI Lumens Total light output Footcandle Lumens per square foot Luminous efficacy Lumens per watt Color Rendering Index Color accuracy vs reference Color temperature Warm to cool appearance Lighting power density Watts per square foot
HVAC Efficiency Conversions HV EER = 3.412 × COP | kW/ton = 12 ÷ EER COP: cooling over work input EER: Btu/h per watt kW/ton: lower is better COP 5.0 ≈ EER 17.1
R-value vs U-value HV
R-value Measures thermal resistance Higher means better insulation
U-value Measures thermal conductance Lower means better insulation Resistance vs conductance, inverse
Efficiency Metric Picker HV Compare chiller cooling ratio → COP Need Btu/h output per watt → EER Rate whole chiller-plant input → kW/ton Estimate seasonal heating load → Degree days Check envelope thermal resistance → R-value Check envelope thermal conductance → U-value
HVAC Efficiency Metrics HV COP Cooling output over work input EER Btu/h output per watt kW/ton Electrical input per cooling ton R-value Thermal resistance, higher is better U-value Thermal conductance, lower is better Degree days Heating or cooling load driver Psychrometric chart Plots moist-air properties graphically
Envelope Loss Formula HV Loss (Btu) = U × A × HDD × 24 U = 1 ÷ R-value HDD = heating degree days × 24 converts days to hours Divide by heating efficiency for fuel
Setback vs Reset Control CO
Setback Changes setpoint when unoccupied Simple schedule-based strategy
Reset Adjusts setpoint to conditions Tracks outdoor temp or demand Time-based vs condition-based
Control Strategy Picker CO Lower setpoint when unoccupied → Setback Adjust setpoint to conditions → Reset control Time HVAC start before occupancy → Optimum start/stop Flag abnormal equipment behavior → FDD Need zero steady-state offset → PI control React fast to disturbances → PID control
Controls & Automation Terms CO P control Leaves permanent offset error PI control Removes offset over time PID control Adds fast disturbance response Optimum start/stop Times equipment before occupancy Setback Lowers setpoint when unoccupied FDD Flags abnormal equipment behavior
Full Storage vs Partial Storage ST
Full storage Chiller off during on-peak Storage covers entire peak load
Partial storage Chiller runs during on-peak too Load-leveling or demand-limiting mode Chiller off vs chiller assists
Thermal Storage Picker ST Chiller off all on-peak → Full storage Chiller runs steady all day → Load leveling Chiller runs reduced on-peak → Demand limiting Media freezes water solid → Ice storage Media changes phase to store → PCM storage
Energy Storage Terms ST Full storage Chiller off during peak Load leveling Chiller runs constant all day Demand limiting Chiller runs reduced on-peak Round-trip efficiency Usable output over energy stored Ice storage Freezes water for later cooling PCM storage Uses phase-change storage media
Boiler & Steam Terms BO Boiler blowdown Drains water to remove solids Steam trap Releases condensate, holds back steam Failed-open trap Wastes live steam continuously Failed-closed trap Backs up condensate, causes hammer Condensate return Recovers hot water, fuel savings HHV vs LHV Includes vs excludes vapor heat
Distributed Generation Terms GE CHP Captures waste heat for reuse Capacity factor Actual output over rated output Interconnection Utility rules for grid tie-in Net metering Credits exported solar generation Prime mover Engine or turbine driving generator
Industrial Systems Terms IN Compressed air Inefficient, mostly lost as heat Throttling Adds resistance, motor stays full-speed VFD control Slows motor to match demand Cooling tower approach Cold water minus wet-bulb temp Rising approach temp Signals fouling or scaling
Preventive vs Predictive Maintenance OM
Preventive Fixed schedule, regardless of condition Example: replace filter quarterly
Predictive Uses condition data to trigger Vibration, temperature, oil analysis Calendar-based vs condition-based
O&M & Commissioning Terms OM Commissioning Verifies new-building systems as-designed Retrocommissioning Same process, never-commissioned building Recommissioning Repeats process on drifted building Preventive maintenance Fixed schedule regardless of condition Predictive maintenance Condition data triggers service Persistence of savings Savings continuing in later years Functional performance testing Forces system through all modes
Guaranteed vs Shared Savings ESPC ES
Guaranteed savings ESCO guarantees savings level Customer arranges own financing
Shared savings ESCO arranges financing too ESCO carries performance and credit risk Who finances, who bears risk
M&V Option Picker ES Measure one key parameter → IPMVP Option A Measure all retrofit parameters → IPMVP Option B Use whole-facility utility meters → IPMVP Option C Baseline or post data missing → IPMVP Option D ESCO carries performance and credit risk → Shared savings ESPC Customer arranges its own financing → Guaranteed savings ESPC
ESPC & M&V Terms ES ESCO Energy service company, implements ESPC Guaranteed savings ESCO guarantees level, covers shortfalls Shared savings ESCO finances; carries credit risk IPMVP Option A Key parameter measured, rest stipulated IPMVP Option B All retrofit parameters measured IPMVP Option C Whole-facility utility meter data IPMVP Option D Calibrated simulation, missing data
Common Traps
Payback ignores time value Payback: no discounting ≠ NPV/IRR: proper discounting
Power factor is not load factor PF: real vs apparent power ≠ Load factor: avg vs peak demand
kWh vs kW kWh: energy used ≠ kW: power rate, demand
Commissioning vs retrocommissioning Commissioning: new building verification ≠ Retrocommissioning: existing, never-commissioned building
IRR is not a ranking tool IRR: ignores project size ≠ NPV: ranks mutually exclusive projects
Trial questions still count for time 10 trial questions unscored ≠ All 130 must be answered
Open book still needs formula fluency References allowed in binder ≠ Fluency with formulas still required
Last Minute 1 . 130 questions: 120 scored, 10 trial 2 . 4 hours, open-book, open-note, calculator required 3 . Pass = 700 points, not percent 4 . Retake wait: 60 days each time 5 . Renewal: 3 years plus CE credits 6 . EER = 3.412 × COP 7 . kW/ton = 12 ÷ EER 8 . 1 kWh = 3412 Btu 9 . 1 therm = 100000 Btu 10 . Full storage: chiller off on-peak 11 . Partial storage: chiller runs on-peak too 12 . All 14 subject areas mandatory 13 . IPMVP A/B = retrofit isolation 14 . IPMVP C = whole-facility meters
AEE Certified Energy Manager (CEM) Practice Questions 437 questions Study Guide 52 topics Cheat Sheet 86 facts Flashcards 50 cards Shorts 1 short Videos 1 video Blogs 1 blog Free CE Podcast
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