Grandwell now offers an online calculator for computing the annual electrical cost for an outdoor electronic sign, please follow the link to the electrical power cost calculator for electronic signs. The calculator uses the formula, listed below to calculate the estimated annual energy consumption for an electronic display, such as LED displays or incandescent signs. The first step is the calculate the cost per kilowatt year and then the electrical cost per year.

Calculate the Cost Per Kilowatt Year (CPKY). The formula is:
[(hours of daylight per year ) x (electrical cost per kilowatt hour)] +
[(hours of night per year) x (electrical cost per kilowatt hour) x (system's usage during night)]. 
Calculate the Electrical Cost Per Year (ECPY). The formula is:
[(# of pixels x .40 x pixel's wattage) / 1000] x Cost Per Kilowatt Year.
The following assumptions were made in calculating the annual electrical cost value.
 Electrical cost is $0.10 per kilowatt hour.
 Incandescent signs use approximately 30% less power at night. (due to lower brightness).
 LED signs use approximately 40% less power at night. (due to lower brightness).
 On average, 40% of all the lamps in matrix are on at a given time.

On average, there are 12 hours of daylight and 12 hours of night per day in a complete year.
Therefore, 4,380 hours of daylight per year and 4,380 hours of night per year.
For example:
LED Sign: Single sided 16x80 matrix LED sign = 2,560 pixels at 0.27 watt per pixel.
Cost Per Kilowatt Year = (4380 x 0.10) + (4380 x 0.06) = $700.80
Electrical Cost Per Year = [(1280 x 0.40 x 0.27) / 1000] x 700.80 = $96.88
Incandescent Sign: Single sided 16x80 matrix incandescent sign = 2,560 lamps at 3 watt per lamp.
Cost Per Kilowatt Year = (4380 x 0.10) + (4380 x 0.07) = $744.60
Electrical Cost Per Year = [(1280 x 0.40 x 3) / 1000] x 744.60 = $1,143.71
Matrix Size (HxL) 
Total Lamps^{1}  Incandescent Lamp Signs  LED Displays  
Lamp Wattage  (Character Size)^{2} Pixel Wattage  
3  5  12  15  25  30 
(3.5) 0.27 
(6) 0.31 
(8) 0.37 
(18) 1.10 
(28) 1.92 
(35) 4.47 

8x96  768  $686  $1,144  $2,745  $3,431  $5,719  $6,862  $58  $67  $80  $237  $413  $962 
16x96  1,536  $1,372  $2,287  $5,490  $6,682  $11,437  $13,724  $116  $133  $159  $474  $827  $1,925 
24x96  2,304  $2,059  $3,431  $8,235  $10,293  $17,156  $20,587  $174  $200  $239  $710  $1,240  $2,887 
32x96  3,072  $2,745  $4,575  $10,980  $13,724  $22,874  $27,449  $233  $267  $319  $947  $1,653  $3,849 
Note:
1) The signs are single faced. 2) LED sign's character size are in
inches. 3) All values are estimates and based in US Dollar (USD).