U.S. Department of Energy

PAYBACK S TS

The median payback period for product classes and design options analyzed are listed in the table

below.

The output from the payback period analysis is a distribution of paybacks which can sometimes

contain negative values. Occasionally, there can be some very large negative values (for cathode

cutout analyses) which cause instability and distort the mean payback period value. For this

reason, we have chosen to present the median payback period, which we feel is a more

meaningful value. Therefore, for the 10,000 cases analyzed for each lamp/ballast combination,

5000 have payback periods below and 5,000 have payback periods above the median values

shown in the table. It is possible for the median payback period to be negative if the first cost of

the ballast plus lamp is lower for the more efficient technology than for the baseline. We

interpret short negative or positive payback periods (e.g., for 3 lamp non tandem, T8 ERS and 4

lamp T8 ERS) as essentially immediate paybacks. The probability distributions of payback

periods for all design options can be found in the Life Cycle Cost Results section on this website.

EE-RM-97-500 COMMENT 67N

~N ~&-7 

u.s. Department of Energy April 1999 

PAYBACK RESULTS 

The median payback period for product classes and design options analyzed are listed in the table 

below. 

The output from the payback period analysis is a distribution of paybacks which can sometimes 

contain negative values. Occasionally, there can be some very large negative values (for cathode 

cutout analyses) which cause instability and distort the mean payback period value. For this 

reason, we have chosen to present the median payback period, which we feel is a more 

meaningful value. Therefore, for the 10,000 cases analyzed for each lamplballast combination, 

5000 have payback periods below and 5,000 have payback periods above the median values 

shown in the table. It is possible for the median payback period to be negative if the first cost of 

the ballast plus lamp is lower for the more efficient technology than for the baseline. We 

interpret short negative or positive payback periods (e.g., for 3 lamp non tandem, T8 ERS and 4 

lamp T8 ERS) as essentially immediate paybacks. The probability distributions of payback 

periods for all design options can be found in the Life Cycle Cost Results section on this website. 
U.S. Departmentof Energy April 1999

Summary of Payback Periods

Product Class Design Option Sector Median

Payback

Period (yrs)

1F40

T12 CC Commercial 24.6

T12 ERS Commercial 6.5

T8 ERS Commercial 2.7

2F40

T12 CC Commercial 10.8

T12 ERS Commercial 5.4

T8 ERS Commercial 2.5

3F40

Tandem-Wired TI2 CC Commercial 8.9

T12 ERS Commercial 7.1

T8 ERS Commercial 2.4

Not Tandem-Wired T12 CC Commercial 10.8

T12 ERS Commercial 3.0

T8 ERS Commercial -0.1

4F40

T12 CC Commercial 8.1

T12 ERS Commercial 4.5

T8 ERS Commercial 0.3

2F96

T12 EIS Commercial 5.8

T12 EIS Industrial 7.1

2F96HO

T12 CC Commercial 2.3

T12 ERS Commercial 2.6

T12 CC Industrial 3.7

T12 ERS Industrial 3.1

EE-RM-97-500 COMMENT 67N

U.S. Department of Energy 

Product Class 

IF40 

2F40 

3F40 

Tandem-Wired 

2F96 

2F96HO 

Summary of Payback Periods 

Design Option Sector 

T12CC 

T12ERS 

T8 ERS 

T12CC 

T12ERS 

T12CC 

T12ERS Commercial 

T8 ERS Commercial 

T12 EIS Commercial 

T12EIS Industrial 

T12CC Commercial 

T12ERS 

T12CC 

T12ERS 

Median 

Payback 

Period (yrs) 

2.5 

8.9 

7.1 

8.1 

4.5 

0.3 

5.8 

7.1 

April 1999