Building Envelope and Lighting Flashcards
7 cards from real Certified Energy Auditor Certification practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Building Envelope and Lighting flashcards as text
Which factor most significantly reduces the effective R-value of a fiberglass batt insulation in a stud wall assembly?
Answer: Thermal bridging through wood studs
Wood studs have a much lower R-value than cavity insulation, and thermal bridging through studs typically reduces a wall's effective R-value by 15-25% compared to the cavity R-value alone.
An energy auditor finds that a facility's T8 fluorescent lamps operate at 3,000 hours per year and consume 32W each. If replaced with 18W LED tubes producing equal lumens, what is the annual kWh savings per lamp?
Answer: 42 kWh
Power reduction = 32W - 18W = 14W; annual savings = 14W × 3,000 hrs ÷ 1,000 = 42 kWh per lamp per year.
What is the primary function of a low-emissivity (low-e) coating on window glass?
Answer: Reflect long-wave infrared radiation to reduce radiant heat transfer
Low-e coatings reflect long-wave infrared radiation, significantly reducing radiant heat transfer between the glazing surface and building interior, improving window U-factor.
A daylight harvesting control system dims electric lights in response to:
Answer: Available natural daylight measured by a photosensor
Daylight harvesting systems use photosensors to measure ambient light levels and automatically dim electric lighting to maintain target illuminance while maximizing use of natural daylight.
What does the fenestration-to-wall ratio (FWR) describe in building energy analysis?
Answer: The percentage of gross exterior wall area that is glazed
Fenestration-to-wall ratio (FWR) is the ratio of total glazed area to gross above-grade exterior wall area, a key metric in energy codes that limits heat gain/loss through windows.
Which infiltration measurement technique uses tracer gas to determine building air change rates under natural conditions?
Answer: CO2 tracer gas decay method
The tracer gas decay method introduces a measured amount of tracer gas (such as CO2 or SF6) and monitors its concentration decay over time to calculate natural air change rates.
In lighting retrofit analysis, simple payback period is calculated as:
Answer: Installed cost divided by annual energy cost savings
Simple payback period = installed cost ÷ annual energy cost savings, expressing how many years it takes for energy savings to recover the initial investment.