CEM Cheat Sheet 2026

The 30 highest-yield CEM facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. A variable frequency drive (VFD) on a pump or fan saves energy because fan/pump power varies with: → The cube of speed
2. A wind turbine's power output varies with wind speed according to: → A cubic relationship (power ∝ speed³)
3. Utility rebates for energy efficiency projects are typically classified as: → Non-recurring benefits that reduce the net capital cost of the project
4. Degree days are used in building energy analysis to: → Quantify heating or cooling demand based on outdoor temperature deviation from a base
5. What does the Color Rendering Index (CRI) measure? → How accurately a light source renders colors compared to a reference source
6. Thermal energy storage (TES) paired with a chiller plant saves energy cost (not necessarily energy) by: → Shifting chiller operation to off-peak hours when electricity rates are lower
7. When comparing natural gas cost ($/MMBtu) to electricity cost ($/kWh) for energy analysis, the correct conversion factor is: → 1 kWh = 3,412 Btu
8. Net metering allows facilities with on-site generation to: → Credit excess electricity fed back to the grid against future consumption charges
9. In an Energy Savings Performance Contract (ESPC), the contractor's payment is primarily based on: → Verified energy savings achieved after implementation
10. The Investment Tax Credit (ITC) for solar energy systems in the US allows eligible projects to: → Claim a percentage of the installation cost as a direct federal income tax credit
11. A Direct Digital Control (DDC) system differs from pneumatic controls primarily because it: → Uses digital microprocessors and electronic sensors for precise, programmable control
12. An energy audit of a motor-driven system should calculate energy savings from a VFD based on the: → Reduction in shaft speed raised to the third power, per the Affinity Laws
13. High-pressure sodium (HPS) lamps are commonly used in street lighting because they offer: → High efficacy and long lamp life
14. A system of electricity has 52.9 kVA and 50.5 kW. To get the power factor of the entire load to 95%, how many kVARs of capacitance are needed? → 0 kVARs
15. The Modified Accelerated Cost Recovery System (MACRS) is used in energy project financial analysis to: → Determine tax depreciation deductions over the asset's recovery period
16. The US industries and structures with the highest installation rates of electric motors are: → AC Induction
17. A building energy benchmark using ENERGY STAR Portfolio Manager allows a facility manager to: → Compare the building's energy performance against similar buildings nationally
18. The primary purpose of a vestibule (airlock entry) in a commercial building is to: → Reduce infiltration by preventing direct outdoor air connection when doors open
19. An energy project requires a $100,000 investment and generates $25,000 in annual savings over a 10-year life. What is the simple Return on Investment (ROI)? → 150%
20. LED lighting saves energy over fluorescent primarily because it: → Converts more electrical energy to light with less heat loss
21. Heat recovery systems (also known as heat exchangers) are unable to lower temperatures below the hot gas's dew point. → False
22. The 'avoided cost' of energy is most accurately described as: → The cost savings that result from not consuming a unit of energy
23. Vapor retarders in wall assemblies are installed to: → Control moisture diffusion and prevent condensation within the wall cavity
24. Adding continuous exterior insulation to a wall assembly primarily helps by: → Eliminating thermal bridging through framing members
25. Fenestration area strongly affects building energy use because windows typically have: → Much lower R-values than insulated walls, increasing heat transfer significantly
26. A lighting energy audit should measure which of the following? → Lamp wattage, fixture count, operating hours, and ballast losses
27. Low-e (low-emissivity) coatings on window glazing primarily reduce heat transfer by: → Reflecting long-wave infrared radiation to reduce radiative heat exchange
28. The power factor is high when an electric AC induction motor is 15% loaded. → False
29. A Time-of-Use (TOU) electricity rate structure is beneficial for energy managers primarily because it: → Provides opportunities to shift loads to lower-cost off-peak periods
30. How many steam traps have failed in your steam system may be ascertained using a flue gas analyzer. → False