Energy efficiency of electric storage tank water heaters and heat pump water heaters

1.1

This Standard specifies the methods for determining the uniform energy factor for electric storage tank water heaters and heat pump water heaters.

1.2

This Standard

a) establishes minimum energy efficiency levels for electric storage tank water heaters and heat pump water heaters; and

b) includes advanced test methods for cold climate ratings (see Annex B).

1.3

This Standard applies to

a) electric storage tank water heaters

i) with volumes of 7.6 to 454 L (2 to 120 US gal);

ii) having electric heater elements with power inputs ≤ 12 kW; and

iii) designed to heat and store water at a thermostatically controlled temperature equal to or less than 82 °C (180 °F); and

b) heat pump water heaters that have

i) a maximum current rating of ≤ 24 A (including the compressor and all auxiliary equipment such as fans, pumps, controls, and, if on the same circuit, any resistive elements);

ii) a maximum wattage rating ≤ 15 kW;

iii) a single-phase maximum voltage of ≤ 250 V;

iv) volumes of 7.6 to 454 L (2 to 120 US gal); and

v) rated storage volume ≤ 454 L (≤ 120 US gal).

1.4

This Standard does not apply to high-temperature water heaters.

1.5

The tests contained in this Standard are not intended to represent actual efficiencies realized in the field. Instead, these tests provide a standardized method of comparing performance.

1.6

In this Standard, "shall" is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the Standard; "should" is used to express a recommendation or that which is advised but not required; and "may" is used to express an option or that which is permissible within the limits of the Standard.

Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material.

Notes to tables and figures are considered part of the table or figure and may be written as requirements.

Annexes are designated normative (mandatory) or informative (non-mandatory) to define their application.

1.7

The values given in SI units are the units of record for the purposes of this Standard. The values given in parentheses are for information and comparison only.