5D-i 

APPENDIX 5D. ADVANCED IR COATINGS 

TABLE OF CONTENTS 

5D.1 INTRODUCTION ........................................................................................................ 5D-1

5D.2 BACKGROUND .......................................................................................................... 5D-1

5D.2.1 HIR Technology.......................................................................................... 5D-1

5D.2.2 Silverized reflector coating......................................................................... 5D-2

5D.2.3 Alternative method...................................................................................... 5D-2

5D.3 METHOD ..................................................................................................................... 5D-2

5D.3.1 Capsules ...................................................................................................... 5D-2

5D.3.2 Modifying voltage....................................................................................... 5D-3

5D.3.3 Reflector...................................................................................................... 5D-3

5D.4 RESULTS ..................................................................................................................... 5D-4

5D.4.1 ADLT Burners ............................................................................................ 5D-4

5D.4.2 Reflector Losses.......................................................................................... 5D-4

5D.4.2.1 Commercially Available Lamps ............................................... 5D-4

5D.4.2.2 ADLT Burners .......................................................................... 5D-5

5D.5 LONG LIFE.................................................................................................................. 5D-6

5D.6 PRICE ........................................................................................................................... 5D-6

5D.7 CONCLUSION............................................................................................................. 5D-7

LIST OF TABLES 

Table 5D.1 Test Results for Burners with Advanced IR Coating............................................ 5D-4

Table 5D.2 Test Results for Burners with Advanced IR Coating Operating at a Reduced 

Operating Temperature ............................................................................... 5D-4

Table 5D.3 Test Results for Commercially Available HIR Lamps......................................... 5D-4

Table 5D.4 Calculated Efficacies for ADLT Burner-Reflector Assemblies ........................... 5D-5

Table 5D.5 Calculated Efficacy for a Long Life (6,000 hours) IRL using an ADLT 

Advanced IR burner.................................................................................... 5D-6

EE-2006-STD-0131 COMMENT 101
5D-1

5D.1

5D.2

APPENDIX 5D. ADVANCED IR COATINGS 

INTRODUCTION 

 Trial standard level (TSL) 5 for incandescent reflector lamps (IRL) represents a halogen 

infrared reflector (HIR) lamp with the most efficient infrared (IR) glass coatings, reflector 

coatings, or filament designs. Commercially available products currently meet TSL 5 by using a 

silverized reflector coating. One lamp manufacturer currently holds a patent on this technology 

which will not expire until after energy conservation standards take effect. In this chapter the 

Department of Energy (DOE) presents the results of testing performed on lamps that utilize a 

different technology, that is potentially available to all manufacturers, and may possibly be 

utilized to manufacture a lamp that would comply with TSL 5 without the use of the proprietary 

silver technology. In this appendix, DOE investigates not only the resulting lamp efficacy when 

employing the advanced IR coatings, but also investigates manufacturing costs associated with 

this technology. Finally, DOE also explores the potential to use this technology to manufacture 

high-efficacy, long-life IRL. 

BACKGROUND 

5D.2.1 HIR Technology 

In chapter 3 of the technical support document (TSD), DOE discusses IR glass coatings 

as a possible design option. When a lamp contains an IR coating, it reflects more IR radiation 

onto the filament, so if run at the same voltage, the lamp operates at a higher temperature. This 

increase in operating temperature increases light output, which in turn increases efficacy. DOE 

concluded that this technology met the required screening criteria outlined in chapter 4 of the 

TSD and considered it as a design option. 

HIR lamps that are commercially available today use IR coatings with alternating layers 

of two materials, SiO 2 and a second material of either Ta2O5 or Nb2O 5. Typical layer counts 

range from 45 to 75. In contrast, the most efficient HIR lamps have a coating made of three 

materials, SiO 2, Ta2O5 and TiO 2, the latter in the high - index rutile phase. This three material 

coating, described as a HybridTM by Advanced Lighting Technologies Inc. (ADLT) (hereafter 

referred to as advanced IR coating), has an effective IR reflectance significantly higher than that 

of the two-material coatings used in the commercially available examples (described in section 

5D.3.1 below), resulting in enhanced lumen per watt (lm/W) values. 

 

This advanced IR coating is not a developmental product. Developed at ADLT, it has 

been in production on 12 Volt, single-ended burners in Europe for more than two years. 

However, the efficacy level achieved with this coating on the single-ended configuration is lower 

than that realized with the double-ended burners used in the testing described below. 

 

EE-2006-STD-0131 COMMENT 101
5D-2

5D.3

Neither the burner nor the coating provided to DOE requires additional development. 

Both are separately in production at present, not patented, and available to all lamp 

manufacturers. The additional layers lead to a slight increase in manufacturing time compared to 

the coatings currently in use in the market place. 

5D.2.2 Silverized reflector coating 

Though aluminum is most prevalent as a reflector coating in incandescent reflector 

lamps, silver coatings can also be applied. Silver coatings are generally preferred over aluminum 

due to their lower light loss (silver reflects about eight percent more light based on commercially 

available lamps). One manufacturer currently holds a patent on the silverized reflector coating 

technology that will not expire until December 20191. Therefore DOE considered the silverized 

reflector coating to be a proprietary technology (see section VI.B.1 of the final rule Federal 

Register notice for a description of how DOE treats proprietary technologies). However, DOE is 

also aware of technology options that utilize silver to enhance reflector efficiencies but may not 

fall under proprietary restrictions2

 (see section VI.B.2.b of the final rule Federal Register notice 

for a description of these other technologies). However, DOE believes that significant 

uncertainty remains as to the successful implementation of these technologies in commercial 

products at the scale needed to service the IRL market. Therefore, DOE maintained that a 

silverized reflector required proprietary technology and thus investigated an alternative method 

to achieve TSL5. 

5D.2.3 Alternative method 

DOE investigated the possibility that TSL 5 could be achieved without using a silverized 

reflector coating. DOE reviewed design options that met all required screening criteria (see 

chapter 4 for details) and discovered the existence of a more efficient IR coating than that 

currently in use in the lighting industry. 

To prove the effectiveness of this coating, ADLT obtained commercially available 

capsules, applied the advanced IR coating, and sent the capsules to the Lighting Research Center 

(LRC) in Rochester, NY for independent testing. The following sections describe the method the 

LRC used for testing and the results of that testing. 

METHOD 

5D.3.1 Capsules 

ADLT provided the LRC with IR coated halogen burners for evaluation. ADLT informed 

DOE that when used with the two-material coating for which they were originally designed, 

these burners operate at 60 W, delivering 24 lm/W. The design life and temperature are 3000 hrs 

EE-2006-STD-0131 COMMENT 101
5D-3

and 2880 K. They are double-ended, elliptical quartz burners, with lengths of 4.5 cm, excluding 

the electrodes, and minor elliptical axes of 1.0 cm. 

 

 This shape and size readily accommodates use in most IRL, as evidenced by products 

now on the market. ADLT claims that such products exist in R20, BR30, BR40 and PAR38 

formats. In addition, outside the IRL configuration, ADLT claims that a commercially-available 

A-line general service incandescent lamp incorporates a burner of the same shape and 

size. These commercially available examples operate at 120V at various powers. The LRC 

measured the lumens and watts of these capsules according to DOE’s test procedure for testing 

incandescent reflector lamps (title 10 Code of Federal Regulations (CFR) part 430, subpart B, 

appendix R). 

5D.3.2 Modifying voltage 

As mentioned in section 5D.2.1, IR coatings increase the operating temperature of an 

HIR lamp, which in turn decreases the lifetime. According to ADLT, commercially available 

halogen burners with standard IR coatings have rated lifetimes of approximately 3,000 hours 

when operated at 120V. Because the advanced IR coating reflects more IR radiation than the 

standard IR coating, the lamp’s operating temperature increases, resulting in a decrease of lamp 

lifetime. ADLT performed tests and determined that the burners with the advanced IR coatings 

supplied by ADLT have lifetimes of approximately 1,200 hours. In order to determine the 

efficacy of a 3,000 hour lamp with an advanced IR coating, DOE lowered the operating voltage 

of the ADLT burners such that the measured correlated color temperature (CCT) (representative 

of operating temperature) was the same as that of the commercially available lamp with the 

standard IR coating. DOE assumed this modification reasonably approximated a 3,000 hour 

lamp. 

5D.3.3 Reflector 

A burner and reflector combined emit less light than the burner alone due to light losses 

attributable to the reflector. Because the burners provided by ADLT are not sold commercially 

as a reflector lamp assemblies, DOE calculated the potential efficacy of an IRL utilizing an 

advanced IR coated burner. To do this, DOE first calculated the lumen reduction due to 

reflectors in commercially available lamps. DOE then applied these same percentage lumen 

reductions to the burners provided by ADLT. 

 The LRC bought and analyzed five existing lamps from two different manufacturers to 

evaluate the lumen losses due to reflectors. It tested each burner-reflector assembly and burner 

(separate from the reflector) three times and averaged the measured lumens across the three tests. 

Using these average lumens from the burner and the average lumens from the burner-reflector 

assembly, DOE then calculated the percent lumen loss due to each lamp reflector. DOE applied 

this percentage to calculate the lumen loss due to a reflector for the burners supplied by ADLT. 

EE-2006-STD-0131 COMMENT 101
5D-4

5D.4 RESULTS 

5D.4.1 ADLT Burners 

Table 5D.1 shows the average lumens, power, and efficacy of the ADLT burners at 

120V, whereas Table 5D.2 below shows the same metrics with the burners operating at reduced 

temperature. As seen in the tables below, reducing the operating temperature to obtain a lifetime 

of 3,000 hours instead of 1,200 hours results in a decrease in efficacy of about 5.6 lm/W. 

Table 5D.1 Test Results for Burners with Advanced IR Coating 

Reflector 

& Burner 

Burner 

Average Light Output lumens - 2116.9 

Average Power watts - 57.0 

Average Efficacy lm/W - 37.1 

Average Voltage V 120 

Table 5D.2 Test Results for Burners with Advanced IR Coating Operating at a Reduced 

Operating Temperature 

Reflector 

& Burner 

Burner 

Average Light Output lumens - 1513.8 

Average Power watts - 48.1 

Average Efficacy lm/W - 31.5 

Average Voltage V - 107 

5D.4.2 Reflector Losses 

5D.4.2.1 Commercially Available Lamps 

The LRC tested each commercially available burner and burner-aluminum reflector 

assembly three times for repeatability and calculated an average value. The average lumens, 

watts, and efficacies for the five commercially available lamps are shown in Table 5D.3. 

Table 5D.3 Test Results for Commercially Available HIR Lamps 

Reflector & 

Burner 

Burner 

Average Light Output lumens 993.3 1358.3 

Average Power watts 61.3 61.7 

Manufacturer 

A 

Average Efficacy lm/W 16.2 22.0 

Manufacturer Average Light Output lumens 978.0 1151.7 

EE-2006-STD-0131 COMMENT 101
5D-5

A Average Power watts 56.6 56.9 

Average Efficacy lm/W 17.3 20.2 

Average Light Output lumens 983.7 1141.0 

Average Power watts 53.6 53.7 

Manufacturer 

A 

Average Efficacy lm/W 18.4 21.2 

Average Light Output lumens 780.3 975.9 

Average Power watts 51.7 51.8 

Manufacturer 

B 

Average Efficacy lm/W 15.1 18.9 

Average Light Output lumens 1057.0 1349.0 

Average Power watts 62.1 62.3 

Manufacturer 

B 

Average Efficacy lm/W 17.0 21.7 

 As shown in the table above, Manufacturer A’s best reflector maintains 86.2% of the 

light from the capsule alone, whereas the worst reflector maintains 73.1% of the light. 

Manufacturer B’s best reflector maintains 79.9% of the light from the capsule alone, whereas the 

worst reflector maintains 78.4% of the light. Using these percentages, it is possible to calculate a 

best and worst case scenario. The best case scenario would use the reflector that maintains 

86.2% of the light, where as the worst case scenario would use the reflector that maintains 73.1% 

of the light. 

5D.4.2.2 ADLT Burners 

Using the percentages described in the previous section, DOE calculated the most 

efficient and least efficient burner-reflector combination that uses the ADLT burners. Table 

5D.4 shows the results. 

Table 5D.4 Calculated Efficacies for ADLT Burner-Reflector Assemblies 

Reflector & 

Burner 

Burner 

Average Light Output lumens 1305 1513.8 

Average Power watts 48.1 48.1 

Best Case 

Scenario, 

86.2% reflector Average Efficacy lm/W 27.1 31.5 

Average Light Output lumens 1107 1513.8 

Average Power watts 48.1 48.1 

Worst Case 

Scenario, 

73.1% reflector Average Efficacy lm/W 23.0 31.5 

As outlined in section VII.A.2 of the final rule, energy conservation standards for IRL are 

dependent upon the wattage of the lamp. The relevant equation that defines the minimum 

efficacy standard associated with TSL 5 is 6.4P0.27, where P is the rated wattage. If 48W were 

the rated wattage of the lamp in the table above, the corresponding efficacy level at TSL 5 would 

be 18.2 lm/W. With an efficacy of at least 23.0 lm/W, the ADLT burner-reflector assembly 

would meet TSL 5. As TSL 5 represents the highest efficacy level, the ADLT burner-reflector 

assembly would also meet all other TSLs.

EE-2006-STD-0131 COMMENT 101
5D-6

5D.5 LONG LIFE 

As discussed in section 5D.2.1, HIR technology results in lamps operating at higher 

temperatures. This, in turn, decreases lamp lifetime because the tungsten filament evaporates 

more quickly. Therefore, DOE performed an analysis to investigate how utilizing an advanced 

IR coating to meet TSL 5 would affect long-life HIR lamps. 

Using the 9th edition of the IESNA Lighting Handbook3, DOE developed a relationship 

between lifetime, lumens, and wattage for two different lamps. Using the known power, lumens, 

and lifetime for the 3,000 hour improved HIR lamp, DOE was able to calculate the lumens of the 

HIR lamp if it had the same power but a lifetime of 6,000 hours. Table 5D.5 shows the 

calculated lumens and efficacy for a 6,000 hour HIR lamp that employs an advanced IR coating. 

Table 5D.5 Calculated Efficacy for a Long Life (6,000 hours) IRL using an ADLT 

Advanced IR burner 

Reflector & 

Burner 

Average Light Output lumens 1188 

Average Power watts 48.1 

Best Case 

Scenario, 

86.2% reflector Average Efficacy lm/W 24.7 

Average Light Output lumens 1007 

Average Power watts 48.1 

Worst Case 

Scenario, 

73.1% reflector Average Efficacy lm/W 21.0 

As described in section 5D.4.2.2, the minimum efficacy requirement at each TSL varies 

based on the rated wattage of the lamp. If the rated wattage of the above lamp were 48W, the 

corresponding minimum efficacy requirement at TSL 5 would be 18.2 lm/W. As shown in Table 

5D.5, both the best case and worst case scenarios meet TSL 5. However, DOE recognizes that 

these efficacies do not represent lamp efficacies under mass production. Therefore, DOE cannot 

conclusively determine that long-life lamps wouild be available at TSL5. 

5D.6 PRICE 

To consider this advanced IR technology as an alternate technology pathway to achieve 

TSL5, DOE also analyzed potential manufacturing cost and price impacts to this technology. 

ADLT provided DOE with estimates of the cost of applying the advanced IR coating described 

in section 5D.2.1 to an existing capsule. It estimated the cost to the lamp manufacturer of adding 

the advanced IR coating to be $0.68 per burner if one million capsules were coated per year4. 

Lamp manufacturers have the option of paying ADLT to apply the advanced IR coating or 

acquiring a machine and coating their own lamps. ADLT expects the price to decrease to $0.20 

per burner if 500 million or more capsules were coated per year. 

EE-2006-STD-0131 COMMENT 101
5D-7

5D.7

To best determine the price of a lamp with an advanced IR coating, DOE added the 

incremental cost of the advanced IR coating to the price of a lamp at TSL 4 (see TSD chapter 7). 

TSL 4 is represented by a HIR lamp with a standard IR coating and a 4,000 hour lifetime. 

ADLT estimated the cost of a standard IR coating, described in section 5D.2.1, to be $0.50 per 

burner if one million capsules were coated per year, decreasing to $0.15 per burner if 500 million 

or more burners were coated per year. Therefore, based on these numbers, the incremental cost 

to manufacturers of the advanced coating would be approximately $0.18 per burner in small 

quantities or $0.05 per burner in large quantities. 

In consideration of the current state of the technology and its production volume, a lamp 

currently manufactured with this advanced IR coating technology would be subject to lower 

volume cost estimates. In the manufacturer impact analysis (MIA), DOE used a multiplier of 2.3 

to calculate the end-user price given the cost to the lamp manufacturer. Using this multiplier, the 

manufacturer cost differential between a standard IR coated lamp and an advanced IR coated 

lamp results in an incremental cost of $0.41 to the end user. Adding this incremental cost to the 

price of a lamp at TSL 4, DOE calculates the medium price of a PAR38 lamp with an advanced 

IR coating at TSL 5 to be $7.91 and calculates the medium price of a PAR30 lamp to be $7.34. 

CONCLUSION 

As shown in section 5D.4.2.2, testing indicates that it is possible to achieve TSL 5 

without using a silverized reflector. An advanced IR coating, which, to DOE’s knowledge, 

would be available to all lamp manufacturers, can likely be used to meet TSL 5. In addition, as 

shown in section 5D.5, TSL 5 does not appear to eliminate long-life lamps from the market. 

Using a relationship derived from the IESNA Lighting Handbook, DOE tentatively concluded 

that a 6,000 lamp with an advanced IR coating could still achieve TSL 5. 

 In section 5D.6, DOE calculated the cost of a lamp with an advanced IR coating by 

adding the incremental cost of the coating to the price of a lamp at TSL 4. The analysis found 

these prices to be comparable with IRL that meet TSL 5 and utilize the proprietary silverized 

reflector technology. 

 Although these results show that IRL with an advanced IR coating can meet and exceed 

TSL5, DOE does not believe that this data is representative of the efficacy these lamps will 

achieve when manufactured on a large scale. Large scale production will likely result in 

decreased efficacy, though the magnitude of this reduction is uncertain (see section VI.B.2a of 

the final rule Federal Register notice for more details). Therefore, DOE cannot conclusively 

determine the performance of lamps utilizing the advanced IR coatings when manufactured on a 

large scale. 

EE-2006-STD-0131 COMMENT 101
5D-8

 

REFERENCES 

1

 Zhao, Tianji, et al. “Protected Coating for Energy Efficient Lamp.” U.S. Patent 6,773,141. 

August 10, 2004. 

2

 Deposition Sciences Incorporated. In Development ─ New, Improved & Enhanced Silver 

Coating. (Last Accessed July 7, 2009) 

<http://www.depsci.com/Documents/SubHeading/DSIannouncesEcoWhiteFINAL.pdf> 

3

 Rae, Mark S., ed. The IESNA Lighting Handbook, Reference & Application, 9th edition, New 

York, NY, IESNA 2000. 

4

 Boling, Norm. <bolingn@depsci.com> “FW: pricing” 8 December 2008. Personal email. (9 

December 2008). 

EE-2006-STD-0131 COMMENT 101