HERS Water Heating Systems 3

Question 1

Which RESNET/ANSI standard governs water heating energy calculations in HERS ratings?

Accepted Answer

ANSI/RESNET/ICC 301-2014 (and subsequent amendments)

Answer

ANSI/RESNET 380-2019

Answer

ASHRAE Standard 62.2-2016

Answer

ANSI/ASHRAE/IESNA 90.1-2016

Question 2

What impact does replacing a gas storage water heater with a gas tankless (on-demand) water heater typically have on the HERS Index?

Accepted Answer

Tankless heaters typically lower the HERS Index by eliminating storage tank standby losses

Answer

No impact; both types are treated identically in HERS calculations

Answer

Tankless heaters increase the HERS Index due to higher combustion losses

Answer

Tankless heaters lower the HERS Index only if installed outdoors

Question 3

A HERS rater evaluating a home with a water heater located in an unconditioned garage should ensure what is accurately modeled?

Accepted Answer

That the ambient garage temperature is accounted for, as it affects standby heat losses from the tank

Answer

Only that the fuel type matches the energy model

Answer

That the water heater is located within 20 feet of the main living area

Answer

That the water heater has been pressure-tested prior to the rating

Question 4

From an energy perspective in HERS ratings, what is the primary purpose of a hot water recirculation system?

Accepted Answer

To ensure hot water is quickly available at fixtures, reducing water waste from purging cooled water

Answer

To increase water pressure throughout the home

Answer

To heat the home using excess water heater capacity

Answer

To reduce water heater cycling losses by maintaining constant flow

Question 5

In HERS rating calculations, how is an electric heat pump water heater (HPWH) treated differently from a standard electric resistance water heater?

Accepted Answer

The HPWH's higher UEF is credited, resulting in lower modeled water heating energy consumption

Answer

They are treated identically since both are electric appliances

Answer

HPWHs receive a penalty because the compressor uses additional electricity

Answer

HPWHs are only credited if paired with a solar PV system

Question 6

For HERS verification, what must a rater confirm about an installed water heater to properly credit its efficiency?

Accepted Answer

That the unit's UEF or EF rating, model number, and fuel type match what was entered in the HERS software

Answer

Only that the fuel type matches the energy model

Answer

That the water heater is located within 20 feet of the main living area

Answer

That the water heater has been in service for at least one year

Question 7

Which of the following hot water distribution improvements would most directly earn a HERS distribution efficiency credit?

Accepted Answer

Installing a structured plumbing system with a central manifold and small-diameter individual home runs

Answer

Increasing water heater tank size from 40 to 80 gallons

Answer

Adding a second water heater in a remote bathroom addition

Answer

Increasing the water heater setpoint from 120°F to 140°F