Note: Effective February 10, 2014, manufacturers must make representations of energy efficiency, including certifications of compliance, using appendix D. Compliance with DOE's amended standards for clothes dryers, and corresponding use of the test procedures at appendix D1 for all representations, including certifications of compliance, is required as of January 1, 2015. Manufacturers must use a single appendix for all representations, including certifications of compliance, and may not use appendix D for certain representations and appendix D1 for other representations. The procedures in appendix D2 need not be performed to determine compliance with energy conservation standards for clothes dryers at this time. However, manufacturers may elect to use the amended appendix D, D1 or D2 early.
1. Definitions
1.1 “AHAM” means the Association of Home Appliance Manufacturers.
1.2 “Bone dry” means a condition of a load of test clothes which has been dried in a dryer at maximum temperature for a minimum of 10 minutes, removed and weighed before cool down, and then dried again for 10-minute periods until the final weight change of the load is 1 percent or less.
1.3 “Compact” or compact size” means a clothes dryer with a drum capacity of less than 4.4 cubic feet.
1.4 “Cool down” means that portion of the clothes drying cycle when the added gas or electric heat is terminated and the clothes continue to tumble and dry within the drum.
1.5 “Cycle” means a sequence of operation of a clothes dryer which performs a clothes drying operation, and may include variations or combinations of the functions of heating, tumbling and drying.
1.6 “Drum capacity” means the volume of the drying drum in cubic feet.
1.7 “HLD-1” means the test standard promulgated by AHAM and titled “AHAM Performance Evaluation Procedure for Household Tumble Type Clothes Dryers”, June 1974, and designated as HLD-1.
1.8 “HLD-2EC” means the test standard promulgated by AHAM and titled “Test Method for Measuring Energy Consumption of Household Tumble Type Clothes Dryers,” December 1975, and designated as HLD-2EC.
1.9 “Standard size” means a clothes dryer with a drum capacity of 4.4 cubic feet or greater.
1.10 “Moisture content” means the ratio of the weight of water contained by the test load to the bone-dry weight of the test load, expressed as a percent.
1.11 “Automatic termination control” means a dryer control system with a sensor which monitors either the dryer load temperature or its moisture content and with a controller which automatically terminates the drying process. A mark or detent which indicates a preferred automatic termination control setting must be present if the dryer is to be classified as having an “automatic termination control.” A mark is a visible single control setting on one or more dryer controls.
1.12 “Temperature sensing control” means a system which monitors dryer exhaust air temperature and automatically terminates the dryer cycle.
1.13 “Moisture sensing control” means a system which utilizes a moisture sensing element within the dryer drum that monitors the amount of moisture in the clothes and automatically terminates the dryer cycle.
2. Testing Conditions
2.1 Installation. Install the clothes dryer in accordance with manufacturer's instructions as shipped with the unit. If the manufacturer's instructions do not specify the installation requirements for a certain component, it shall be tested in the as-shipped condition. The dryer exhaust shall be restricted by adding the AHAM exhaust simulator described in 3.3.5 of HLD-1. All external joints should be taped to avoid air leakage. Disconnect all lights, such as task lights, that do not provide any information related to the drying process on the clothes dryer and that do not consume more than 10 watts during the clothes dryer test cycle. Control setting indicator lights showing the cycle progression, temperature or dryness settings, or other cycle functions that cannot be turned off during the test cycle shall not be disconnected during the active mode test cycle.
2.2 Ambient temperature and humidity. Maintain the room ambient air temperature at 75 ±3 °F and the room relative humidity at 50±10 percent relative humidity.
2.3 Energy supply.
2.3.1 Electrical supply. Maintain the electrical supply at the clothes dryer terminal block within 1 percent of 120/240 or 120/208Y or 120 volts as applicable to the particular terminal block wiring system and within 1 percent of the nameplate frequency as specified by the manufacturer. If the dryer has a dual voltage conversion capability, conduct test at the highest voltage specified by the manufacturer.
2.3.2 Gas supply.
2.3.2.1 Natural gas. Maintain the gas supply to the clothes dryer at a normal inlet test pressure immediately ahead of all controls at 7 to 10 inches of water column. If the clothes dryer is equipped with a gas appliance pressure regulator, the regulator outlet pressure at the normal test pressure shall be within ±10 percent of the value recommended by the manufacturer in the installation manual, on the nameplate sticker, or wherever the manufacturer makes such a recommendation for the basic model. The hourly Btu rating of the burner shall be maintained within ±5 percent of the rating specified by the manufacturer. If the requirement to maintain the hourly Btu rating of the burner within ±5 percent of the rating specified by the manufacturer cannot be achieved under the allowable range in gas inlet test pressure, the orifice of the gas burner should be modified as necessary to achieve the required Btu rating. The natural gas supplied should have a heating value of approximately 1,025 Btus per standard cubic foot. The actual heating value, Hn2, in Btus per standard cubic foot, for the natural gas to be used in the test shall be obtained either from measurements made by the manufacturer conducting the test using a standard continuous flow calorimeter as described in section 2.4.6 or by the purchase of bottled natural gas whose Btu rating is certified to be at least as accurate a rating as could be obtained from measurements with a standard continuous flow calorimeter as described in section 2.4.6.
2.3.2.2 Propane gas. Maintain the gas supply to the clothes dryer at a normal inlet test pressure immediately ahead of all controls at 11 to 13 inches of water column. If the clothes dryer is equipped with a gas appliance pressure regulator, the regulator outlet pressure at the normal test pressure shall be within ±10 percent of the value recommended by the manufacturer in the installation manual, on the nameplate sticker, or wherever the manufacturer makes such a recommendation for the basic model. The hourly Btu rating of the burner shall be maintained within ±5 percent of the rating specified by the manufacturer. If the requirement to maintain the hourly Btu rating of the burner within ±5 percent of the rating specified by the manufacturer cannot be achieved under the allowable range in gas inlet test pressure, the orifice of the gas burner should be modified as necessary to achieve the required Btu rating. The propane gas supplied should have a heating value of approximately 2,500 Btus per standard cubic foot. The actual heating value, Hp, in Btus per standard cubic foot, for the propane gas to be used in the test shall be obtained either from measurements made by the manufacturer conducting the test using a standard continuous flow calorimeter as described in section 2.4.6 or by the purchase of bottled gas whose Btu rating is certified to be at least as accurate a rating as could be obtained from measurement with a standard continuous calorimeter as described in section 2.4.6.
2.4 Instrumentation. Perform all test measurements using the following instruments as appropriate.
2.4.1 Weighing scale for test cloth. The scale shall have a range of 0 to a maximum of 60 pounds with a resolution of at least 0.2 ounces and a maximum error no greater than 0.3 percent of any measured value within the range of 3 to 15 pounds.
2.4.1.2 Weighing scale for drum capacity measurements. The scale should have a range of 0 to a maximum of 600 pounds with resolution of 0.50 pounds and a maximum error no greater than 0.5 percent of the measured value.
2.4.2 Kilowatt-hour meter. The kilowatt-hour meter shall have a resolution of 0.001 kilowatt-hours and a maximum error no greater than 0.5 percent of the measured value.
2.4.3 Gas meter. The gas meter shall have a resolution of 0.001 cubic feet and a maximum error no greater than 0.5 percent of the measured value.
2.4.4 Dry and wet bulb psychrometer. The dry and wet bulb psychrometer shall have an error no greater than ±1 °F. A relative humidity meter with a maximum error tolerance expressed in °F equivalent to the requirements for the dry and wet bulb psychrometer or with a maximum error tolerance of ±2 percent relative humidity would be acceptable for measuring the ambient humidity.
2.4.5 Temperature. The temperature sensor shall have an error no greater than ±1 °F.
2.4.6 Standard Continuous Flow Calorimeter. The Calorimeter shall have an operating range of 750 to 3,500 Btu per cubic feet. The maximum error of the basic calorimeter shall be no greater than 0.2 percent of the actual heating value of the gas used in the test. The indicator readout shall have a maximum error no greater than 0.5 percent of the measured value within the operating range and a resolution of 0.2 percent of the full scale reading of the indicator instrument.
2.5 Lint trap. Clean the lint trap thoroughly before each test run.
2.6 Test cloths.
2.6.1 Energy test cloth. The energy test cloth shall be clean and consist of the following:
(a) Pure finished bleached cloth, made with a momie or granite weave, which is a blended fabric of 50 percent cotton and 50 percent polyester and weighs within + 10 percent of 5.75 ounces per square yard after test cloth preconditioning and has 65 ends on the warp and 57 picks on the fill. The individual warp and fill yarns are a blend of 50 percent cotton and 50 percent polyester fibers.
(b) Cloth material that is 24 inches by 36 inches and has been hemmed to 22 inches by 34 inches before washing. The maximum shrinkage after five washes shall not be more than four percent on the length and width.
(c) The number of test runs on the same energy test cloth shall not exceed 25 runs.
2.6.2 Energy stuffer cloths. The energy stuffer cloths shall be made from energy test cloth material and shall consist of pieces of material that are 12 inches by 12 inches and have been hemmed to 10 inches by 10 inches before washing. The maximum shrinkage after five washes shall not be more than four percent on the length and width. The number of test runs on the same energy stuffer cloth shall not exceed 25 runs after test cloth preconditioning.
2.6.3 Test Cloth Preconditioning.
A new test cloth load and energy stuffer cloths shall be treated as follows:
(1) Bone dry the load to a weight change of ±1 percent, or less, as prescribed in Section 1.2.
(2) Place test cloth load in a standard clothes washer set at the maximum water fill level. Wash the load for 10 minutes in soft water (17 parts per million hardness or less), using 6.0 grams of AHAM Standard Test Detergent, IIA, per gallon of water. Wash water temperature is to controlled at 140°±5 °F (60° ±2.7 °C). Rinse water temperature is to be controlled at 100° ±5 °F (37.7 ±2.7 °C).
(3) Rinse the load again at the same water temperature.
(4) Bone dry the load as prescribed in Section 1.2 and weigh the load.
(5) This procedure is repeated until there is a weight change of one percent or less.
(6) A final cycle is to be a hot water wash with no detergent, followed by two warm water rinses.
2.7 Test loads.
2.7.1 Compact size dryer load. Prepare a bone-dry test load of energy cloths which weighs 3.00 pounds ±.03 pounds. Adjustments to the test load to achieve the proper weight can be made by the use of energy stuffer cloths, with no more than five stuffer cloths per load. Dampen the load by agitating it in water whose temperature is 100° ±5 °F and consists of 0 to 17 parts per million hardness for approximately two minutes in order to saturate the fabric. Then, extract water from the wet test load by spinning the load until the moisture content of the load is between 66.5 percent to 73.5 percent of the bone-dry weight of the test load.
2.7.2 Standard size dryer load. Prepare a bone-dry test load of energy cloths which weighs 7.00 pounds ±.07 pounds. Adjustments to the test load to achieve the proper weight can be made by the use of energy stuffer cloths, with no more than five stuffer cloths per load. Dampen the load by agitating it in water whose temperature is 100° ±5 °F and consists of 0 to 17 parts per million hardness for approximately two minutes in order to saturate the fabric. Then, extract water from the wet test load by spinning the load until the moisture content of the load is between 66.5 percent to 73.5 percent of the bone-dry weight of the test load.
2.7.3 Method of loading. Load the energy test cloths by grasping them in the center, shaking them to hang loosely and then dropping them in the dryer at random.
2.8 Clothes dryer preconditioning. Before any test cycle, operate the dryer without a test load in the non-heat mode for 15 minutes or until the discharge air temperature is varying less than 1 °F for 10 minutes, which ever is longer, in the test installation location with the ambient conditions within the specified rest condition tolerances of 2.2.
3. Test Procedures and Measurements
3.1 Drum Capacity. Measure the drum capacity by sealing all openings in the drum except the loading port with a plastic bag, and ensure that all corners and depressions are filled and that there are no extrusions of the plastic bag through any openings in the interior of the drum. Support the dryer's rear drum surface on a platform scale to prevent deflection of the dryer, and record the weight of the empty dryer. Fill the drum with water to a level determined by the intersection of the door plane and the loading port (i.e., the uppermost edge of the drum that is in contact with the door seal). Record the temperature of the water and then the weight of the dryer with the added water and then determine the mass of the water in pounds. Add the appropriate volume to account for any space in the drum interior not measured by water fill (e.g., the space above the uppermost edge of the drum within a curved door) and subtract the appropriate volume to account for space that is measured by water fill but cannot be used when the door is closed (e.g., space occupied by the door when closed). The drum capacity is calculated as follows:
C = w/d ±volume adjustment
C = capacity in cubic feet.
w = mass of water in pounds.
d = density of water at the measured temperature in pounds per cubic foot.
3.2 Dryer loading. Load the dryer as specified in 2.7.
3.3 Test cycle. Operate the clothes dryer at the maximum temperature setting and, if equipped with a timer, at the maximum time setting. Any other optional cycle settings that do not affect the temperature or time settings shall be tested in the as-shipped position. If the clothes dryer does not have a separate temperature setting selection on the control panel, the maximum time setting should be used for the drying test cycle. Dry the test load until the moisture content of the test load is between 2.5 percent and 5.0 percent of the bone-dry weight of the test load, but do not permit the dryer to advance into cool down. If required, reset the timer or automatic dry control.
3.4 Data recording. Record for each test cycle:
3.4.1 Bone-dry weight of the test load described in 2.7.
3.4.2 Moisture content of the wet test load before the test, as described in 2.7.
3.4.3 Moisture content of the dry test load obtained after the test described in 3.3.
3.4.4 Test room conditions, temperature and percent relative humidity described in 2.2.
3.4.5 For electric dryers—the total kilowatt-hours of electric energy, Et, consumed during the test described in 3.3.
3.4.6 For gas dryers:
3.4.6.1 Total kilowatt-hours of electrical energy, Ete, consumed during the test described in 3.3.
3.4.6.2 Cubic feet of gas per cycle, Etg, consumed during the test described in 3.3.
3.4.6.3 On gas dryers using a continuously burning pilot light—the cubic feet of gas, Epg, consumed by the gas pilot light in one hour.
3.4.6.4 Correct the gas heating value, GEF, as measured in 2.3.2.1 and 2.3.2.2, to standard pressure and temperature conditions in accordance with U.S. Bureau of Standards, circular C417, 1938. A sample calculation is illustrated in appendix E of HLD-1.
3.5 Test for automatic termination field use factor credits. Credit for automatic termination can be claimed for those dryers which meet the requirements for either temperature-sensing control, 1.12, or moisture sensing control, 1.13, and having present the appropriate mark or detent feed defined in 1.11.
4. Calculation of Derived Results From Test Measurements
4.1 Total per-cycle electric dryer energy consumption. Calculate the total electric dryer energy consumption per cycle, Ece expressed in kilowatt-hours per cycle and defined as:
Ece = [66/Ww−Wd)] × Ett × FU
Et = the energy recorded in 3.4.5.
66 = an experimentally established value for the percent reduction in the moisture content of the test load during a laboratory test cycle expressed as a percent.
FU = Field use factor.
= 1.18 for time termination control systems.
= 1.04 for automatic control systems which meet the requirements of the definitions for automatic termination controls in 1.11.1, 1.12 and 1.13.
Ww = the moisture content of the wet test load as recorded in 3.4.2.
Wd = the moisture content of the dry test load as recorded in 3.4.3.
4.2 Per-cycle gas dryer electrical energy consumption. Calculate the gas dryer electrical energy consumption per cycle, Ege, expressed in kilowatt-hours per cycle and defined as:
Ege = [66/(Ww−Wd)] × Ete × FU
Ete = the energy recorded in 3.4.6.1
FU, 66, Ww, Wd as defined in 4.1
4.3 Per-cycle gas dryer gas energy consumption. Calculate the gas dryer gas energy consumption per cycle, Ege, expressed in Btu's per cycle as defined as:
Egg = [66/(Ww−Wd)] × Etg × FU × GEF
Etg = the energy recorded in 3.4.6.2
GEF = corrected gas heat value (Btu per cubic feet) as defined in 3.4.6.4
FU, 66, Ww Wd as defined in 4.1
4.4 Per-cycle gas dryer continuously burning pilot light gas energy consumption. Calculate the gas dryer continuously burning pilot light gas energy consumption per cycle, Eup expressed in Btu's per cycle and defined as:
Eup = Epg × (8760 − 140 / 416) × GEF
Epg = the energy recorded in 3.4.6.3
8760 = number of hours in a year
416 = representative average number of clothes dryer cycles in a year
140 = estimated number of hours that the continuously burning pilot light is on during the operation of the clothes dryer for the representative average use cycle for clothes dryers (416 cycles per year)
GEF as defined in 4.3
4.5 Total per-cycle gas dryer gas energy consumption expressed in Btu's. Calculate the total gas dryer energy consumption per cycle, Eg, expressed in Btu's per cycle and defined as:
Eg = Egg + Eup
Egg as defined in 4.3
Eup as defined in 4.4
4.6 Total per-cycle gas dryer energy consumption expressed in kilowatt-hours. Calculate the total gas dryer energy consumption per cycle, Ecg, expressed in kilowatt-hours per cycle and defined as:
Ecg + Ege + (Eg/3412 Btu/k Wh)
Ege as defined in 4.2
Eg as defined in 4.5
[46 FR 27326, May 19, 1981, as amended at 76 FR 1032, Jan. 6, 2011; 78 FR 49644, Aug. 14, 2013]
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