B-i

APPENDIX B. ENERGY USE CALCULATION

TABLE OF CONTENTS

B.1 INTRODUCTION.....................................................................................................1

B.2 R20 SHORT LAMP ENERGY USE..........................................................................1
B-1

APPENDIX B. ENERGY USE CALCULATION

B.1 INTRODUCTION

This appendix provides the U.S. Department of Energy’s (DOE’s) calculation of energy 

use for 100 watt (W) R20a short (having a maximum overall length (MOL) of 3 and 5/8 (or 

3.625) inches) lamps (hereafter “R20 short lamps”). Specifically, DOE used estimates to assume 

the installed stock of R20 short lamps and the 2010 U.S. Lighting Market Characterization (2010 

LMC)

b to develop average annual operating hours. DOE determined the annual energy usage of 

R20 short lamps to be insignificant. The process is explained in greater detail in the following 

section.

B.2 R20 SHORT LAMP ENERGY USE

DOE found that approximately 2,352,000 inground pools and spas use lighting in the 

United States, based on information provided by the National Association of Pool and Spa 

Professionals.

c However, this does not reflect pools and spas that specifically use R20 short 

lamps. The National Electrical Manufacturers Association (NEMA) submitted lamp 

manufacturer data that indicated there are over 5,000,000 existing pools and spas installed in the 

United States that must use R20 short lamps due to their existing fixture design and safety 

requirements. (NEMA, No. 7 at p. 2)d DOE selected NEMA’s more conservative estimate to 

assess the installed stock of R20 short lamps.

DOE used the 2010 LMC to estimate usage of the R20 short lamps. Because the LMC has 

no estimate for the operating hours of a pool or spa, DOE used the estimate that most closely 

represented this category. DOE determined that the average daily operating hours for the 

Other/Unknown room type for the Single Family Detached Home residence type are the most 

applicable usage assumption for R20 short lamps. Therefore, DOE assumed average annual 

operating hours of 365 hours; this figure corresponded with feedback DOE had received on R20 

short lamp usage. DOE also learned through manufacturer interviews that only one R20 short 

lamp is typically installed in an inground pool or spa. DOE then used these assumptions, along 

with the rated wattage of 100W, to calculate that R20 short lamps installed in the United States 

use an estimated 0.0006 quads of energy per year.

 a “R” denotes a reflector lamp type and “20” denotes diameter in 1/8 inch increments, which translates to 2.5 inches. b U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, “2010 U.S. Lighting Market 

Characterization.” Available at: http://apps1.eere.energy.gov/buildings/publications/pdfs/ssl/2010-lmc-final-jan2012.pdf. c In an interview conducted January 18, 2012. d A notation in the form “NEMA, No. 7 at p. 2” identifies a written comment that DOE has received and has 

included in the docket of this rulemaking. This particular notation refers to a comment: (1) submitted by the NEMA; 

(2) in document number 7 of the docket; and (3) on page 2 of that document.