NABCEP Energy Efficiency & Conservation Techniques 3 — Questions and Answers
Question 1: Which federal program sets minimum energy efficiency standards for appliances and equipment in the US?
- ENERGY STAR
- DOE Appliance Standards Program (Correct answer)
- ASHRAE 90.1
- EPA WaterSense
Correct answer: DOE Appliance Standards Program
The DOE Appliance Standards Program establishes legally mandatory minimum efficiency levels for appliances, lighting, and equipment sold in the US.
Question 2: What is the primary purpose of a duct blaster test?
- Measure airflow at each supply register
- Quantify air leakage from the duct system (Correct answer)
- Assess filter efficiency in the air handler
- Calibrate thermostat setpoints
Correct answer: Quantify air leakage from the duct system
A duct blaster pressurizes the duct system and measures leakage to identify where conditioned air is being lost before delivery.
Question 3: The Seasonal Energy Efficiency Ratio (SEER) is used to rate the efficiency of:
- Gas furnaces
- Air-source heat pumps and air conditioners (Correct answer)
- Water heaters
- Heat recovery ventilators
Correct answer: Air-source heat pumps and air conditioners
SEER measures cooling output divided by electrical energy input over a typical cooling season, used for rating air conditioners and heat pump cooling mode.
Question 4: In an energy audit, the measure of cost-effectiveness comparing first-year savings to installation cost is called:
- Net Present Value (NPV)
- Internal Rate of Return (IRR)
- Simple Payback Period (Correct answer)
- Levelized Cost of Energy (LCOE)
Correct answer: Simple Payback Period
Simple payback period divides upfront cost by annual energy savings to determine how many years until the investment is recovered.
Question 5: Which window property most directly determines how much solar heat gain enters a building?
- Visible Transmittance (VT)
- Solar Heat Gain Coefficient (SHGC) (Correct answer)
- U-factor
- Air Leakage Rating
Correct answer: Solar Heat Gain Coefficient (SHGC)
SHGC measures the fraction of incident solar radiation that passes through a window as heat; lower SHGC reduces unwanted solar heat gain.
Question 6: A variable-speed drive (VSD) on a pump motor reduces energy consumption because:
- It increases system static pressure at all flow rates
- Fan/pump power varies with the cube of speed, so small speed reductions yield large savings (Correct answer)
- It converts AC power to DC for higher efficiency
- It eliminates the need for filters in air-handling systems
Correct answer: Fan/pump power varies with the cube of speed, so small speed reductions yield large savings
Per the affinity laws, power varies with the cube of rotational speed; reducing speed by 20% cuts power demand by nearly 50%.
Question 7: Demand-controlled ventilation (DCV) adjusts outdoor air intake based on:
- Outdoor temperature and humidity
- CO₂ concentration as a proxy for occupancy (Correct answer)
- Time-of-day scheduling only
- Building pressurization relative to outdoors
Correct answer: CO₂ concentration as a proxy for occupancy
DCV uses CO₂ sensors to modulate outdoor air ventilation rates in proportion to actual occupancy, reducing unnecessary ventilation energy.
NABCEP Energy Efficiency & Conservation Techniques 3
Which federal program sets minimum energy efficiency standards for appliances and equipment in the US?