Are you a candidate for delamping?

To see if delamping will pay off for you, please find your hours of operation per week and your approximate cost of energy per kilowatt hour (kWh).  The figure listed is the energy savings per fixture, per year.  If the figure falls in either green area, then your ROI (Return On Investment) will be one year or less.  This is the amount of time it takes for the energy savings to pay for the cost of new lamps.

$0.05

$0.10

$0.15

$0.20

$0.25

$0.30

 energy cost per kWh

40

$10.11

$20.23

$30.34

$40.45

$50.56

$60.68

50

$12.64

$25.28

$37.92

$50.56

$63.21

$75.85

60

$15.17

$30.34

$45.51

$60.68

$75.85

$91.02

70

$17.70

$35.40

$53.09

$70.79

$88.49

$106.19

80

$20.23

$40.45

$60.68

$80.90

$101.13

$121.36

90

$22.75

$45.51

$68.26

$91.02

$113.77

$136.52

100

$25.28

$50.56

$75.85

$101.13

$126.41

$151.69

168

$42.47

$84.95

$127.42

$169.90

$212.37

$254.85

hours per week

 

ROI in two or more years

 

ROI in less than two years but more than one year

 

ROI in less than one year but greater than six months

 

ROI in less than six months


The calculated savings are derived from the sum of two numbers, calculated as follows:

80 watts x hours per week x 52 weeks per year / 1000 = kWh (kilowatt hours).  kWh x electric rate = $ saved on lighting.

80 watts x hours per week x 26 weeks per year / 1000 = kWh.  kWh x .431 (a constant) x electric rate = $ saved on air conditioning. 

Since our whiter/birghter F40T12 lamps produce 6050 seeable lumens and hold 95% of their brightness over their life (which is guaranteed for 84 months, or over 61,320 hours), then the total savings over the life of the lamps is calculated as follows:

7 years - ROI time x energy rate = savings per fixture.  For example, if your value from the chart above is the cell with 80 hours per week and $.15 energy cost, then the ROI is about one year and the savings per fixture is $60.68.  7 years - 1 year = 6 years x $60.68 =  $364.08 per fixture.  If you have 40 fixtures in your office, this is$14,563.20 over seven years.

Delamping with T8 fluorescents.  

Since the T8 lamp (4713 seeable lumens) typically uses 20% less power than T12 lamps, the process of delamping with two whiter/brghter lamps instead of four is going to deliver 20% less ROI and savings than with T12s.  However, The T8 lamps are only about 50% brighter than those they replace, so a two-for-four swap ends up providing only 75% of the same brightness.  

To see if delamping will pay off for you, please find your hours of operation per week and your approximate cost of energy per kilowatt hour (kWh).  The figure listed is the energy savings per fixture, per year.  If the figure falls in either green area, then your ROI (Return on Investment) will be one year or less.  This is the amount of time it takes for the energy savings to pay for the cost of new lamps.  Here are the tables for the T8 analysis:

$0.05

$0.10

$0.15

$0.20

$0.25

$0.30

 energy cost per kWh

40

$8.09

$16.18

$24.27

$32.36

$40.45

$48.54

50

$10.11

$20.23

$30.34

$40.45

$50.56

$60.68

60

$12.14

$24.27

$36.41

$48.54

$60.68

$72.81

70

$14.16

$28.32

$42.47

$56.63

$70.79

$84.95

80

$16.18

$32.36

$48.54

$64.72

$80.90

$97.08

90

$18.20

$36.41

$54.61

$72.81

$91.02

$109.22

100

$20.23

$40.45

$60.68

$80.90

$101.13

$121.36

168

$33.98

$67.96

$101.94

$135.92

$169.90

$203.88

hours per week

 

ROI in two or more years

 

ROI in less than two years but more than one year

 

ROI in less than one year but greater than six months

 

ROI in less than six months
Since our lamps are guaranteed for seven years (61,320 hours) continuous operation, figure out how many years it takes to recover the cost of the lamps. Subtract that from seven, and multiply the remainder by the annual savings to determine your total savings over seven years, per fixture.

Note:  You will lose about 3000 lumens in brightness with this method.

The calculated savings are derived from the sum of two numbers, calculated as follows:

64 watts x hours per week x 52 weeks per year / 1000 = kWh (kilowatt hours).  kWh x electric rate = $ saved on lighting.

64 watts x hours per week x 26 weeks per year / 1000 = kWh.  kWh x .431 (a constant) x electric rate = $ saved on air conditioning. 

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