NABCEP Energy Efficiency & Conservation Techniques 4

Question 1

Which lighting efficiency metric describes the amount of visible light produced per watt of electrical power consumed?

Accepted Answer

Lumens per watt (efficacy)

Answer

Luminous efficacy (lumens per watt) is the standard measure of how efficiently a light source converts electrical energy into visible light.

Question 2

Earth tube (ground-coupled heat exchanger) systems pre-condition incoming ventilation air by:

Accepted Answer

Exchanging heat with the relatively stable ground temperature

Answer

Buried tubes allow incoming air to exchange heat with stable ground temperatures (55–65°F), pre-warming air in winter and pre-cooling it in summer.

Question 3

A heat recovery ventilator (HRV) differs from an energy recovery ventilator (ERV) primarily because an HRV:

Accepted Answer

Transfers heat only without moving moisture

Answer

An HRV transfers sensible heat only, while an ERV additionally transfers latent energy (moisture), making ERVs better suited for humid climates.

Question 4

In the context of energy-efficient building design, what does 'thermal bridging' refer to?

Accepted Answer

A conductive path through insulation that bypasses its thermal resistance

Answer

Thermal bridges are high-conductivity elements (like metal studs or concrete columns) that allow heat to bypass insulation, reducing overall envelope performance.

Question 5

Which metric is most appropriate for comparing annual energy costs of different heating fuel types?

Accepted Answer

Cost per million BTU (MMBtu) of useful heat delivered

Answer

Cost per MMBtu of useful heat accounts for both fuel price and equipment efficiency, enabling a true apples-to-apples comparison across fuel types.

(NABCEP) Certified North American Board of Certified Energy Practitioners Specialist Practice Test

(NABCEP) Certified North American Board of Certified Energy Practitioners Specialist Practice Test

NABCEP Energy Efficiency & Conservation Techniques 4