# 10 CFR § 429.21 - Residential clothes dryers.

§ 429.21 Residential clothes dryers.

(a) Sampling plan for selection of units for testing.

(1) The requirements of § 429.11 are applicable to clothes dryers; and

(2) For each basic model of clothes dryers a sample of sufficient size shall be randomly selected and tested to ensure that -

(i) Any represented value of estimated annual operating cost, energy consumption or other measure of energy consumption of a basic model for which consumers would favor lower values shall be greater than or equal to the higher of:

(A) The mean of the sample, where:

$\begin{array}{c}\stackrel{—}{x}=\frac{1}{n}\sum _{i=1}^{n}{x}_{i}\\ \text{and,}\stackrel{—}{x}\phantom{\rule{0ex}{0ex}}\text{is the sample mean; n is the number of samples; and}\phantom{\rule{0ex}{0ex}}{x}_{i}\phantom{\rule{0ex}{0ex}}\text{is the}\phantom{\rule{0ex}{0ex}}{i}^{\mathrm{th}}\phantom{\rule{0ex}{0ex}}\text{sample;}\end{array}$

Or,

(B) The upper 97 1/2 percent confidence limit (UCL) of the true mean divided by 1.05, where:

$\begin{array}{c}UCL=\stackrel{—}{x}+{t}_{.975}\left(\frac{s}{\sqrt{n}}\right)\\ \mathrm{And}\phantom{\rule{0ex}{0ex}}\stackrel{—}{x}\phantom{\rule{0ex}{0ex}}\text{is the sample mean; s is the sample standard deviation; n is the number of}\phantom{\rule{0ex}{0ex}}\\ \text{samples; and}\phantom{\rule{0ex}{0ex}}{t}_{0.975}\phantom{\rule{0ex}{0ex}}\text{is the t statistic for a 97.5% one-tailed confidence interval with}\\ \text{n-1 degrees of freedom (from Appendix A).}\end{array}$

and

(ii) Any represented value of the energy factor, combined energy factor, or other measure of energy consumption of a basic model for which consumers would favor higher values shall be less than or equal to the lower of:

(A) The mean of the sample, where:

$\begin{array}{c}\stackrel{—}{x}=\frac{1}{n}\sum _{i=1}^{n}{x}_{i}\\ \text{and,}\stackrel{—}{x}\phantom{\rule{0ex}{0ex}}\text{is the sample mean; n is the number of samples; and}\phantom{\rule{0ex}{0ex}}{x}_{i}\phantom{\rule{0ex}{0ex}}\text{is the}\phantom{\rule{0ex}{0ex}}{i}^{\mathrm{th}}\phantom{\rule{0ex}{0ex}}\text{sample;}\end{array}$

Or,

(B) The lower 97 1/2 percent confidence limit (LCL) of the true mean divided by 0.95, where:

$\begin{array}{c}LCL=\stackrel{—}{x}-{t}_{.975}\left(\frac{s}{\sqrt{n}}\right)\\ \mathrm{And}\phantom{\rule{0ex}{0ex}}\stackrel{—}{x}\phantom{\rule{0ex}{0ex}}\text{is the sample mean; s is the sample standard deviation; n is the number of}\phantom{\rule{0ex}{0ex}}\\ \text{samples; and}\phantom{\rule{0ex}{0ex}}{t}_{0.975}\phantom{\rule{0ex}{0ex}}\text{is the t statistic for a 97.5% one-tailed confidence interval with}\\ \text{n-1 degrees of freedom (from Appendix A).}\end{array}$

(3) The capacity of a basic model reported in accordance with paragraph (b)(2) of this section shall be the mean of the capacities measured for each tested unit of the basic model.

(b) Certification reports.

(1) The requirements of § 429.12 are applicable to clothes dryers; and

(2) Pursuant to § 429.12(b)(13), a certification report shall include the following public product-specific information: When using appendix D, the energy factor in pounds per kilowatt hours (lb/kWh), the capacity in cubic feet (cu ft), the voltage in volts (V) (for electric dryers only), an indication if the dryer has automatic termination controls, and the hourly British thermal unit (Btu) rating of the burner (for gas dryers only); when using appendix D1, the combined energy factor in pounds per kilowatt hours (lb/kWh), the capacity in cubic feet (cu ft), the voltage in volts (V) (for electric dryers only), an indication if the dryer has automatic termination controls, and the hourly Btu rating of the burner (for gas dryers only); when using appendix D2, the combined energy factor in pounds per kilowatt hours (lb/kWh), the capacity in cubic feet (cu ft), the voltage in volts (V) (for electric dryers only), an indication if the dryer has automatic termination controls, the hourly Btu rating of the burner (for gas dryers only), and a list of the cycle setting selections for the energy test cycle as recorded in section 3.4.7 of appendix D2 to Subpart B of Part 430.

[76 FR 12451, Mar. 7, 2011; 76 FR 24767, May 2, 2011, as amended at 78 FR 49644, Aug. 14, 2013]