Posted May 5 2012
We have a lot of track lighting that was using MR 16 metal halide 12 v mostly 20w and some 50w. I had replaced them about a year ago with some Chinese LED 3 w super white. The lighting is amazing and about the same lumins as the 20 w they replaced. Of the 20 pcs I had purchased 2 had quit. Oh well I suspected they may not last. I still intend to buy a bunch more for some other fixtures. I like the super white lighting. Most of our lighting in the house is the 12v MR-16 powered by some large format batteries that are waiting for solar PV install. For now they are charged via a high end charger powered by the grid. Running the calculations it will take 20 years for the lights ROI. But that is at todays dollar. The next time we have an increase in the cost of energy that ROI time will shorten. Just hope they will stand the test of time.
Randen
( As mentioned I had purchased more LEDs only the additional LEDs of greater wattage 3w to 6w and move the 3 w to other areas of the house. But for the calculations lets use the worst case, the higher wattage)
I'm not sure on how I came up with the ROI (20 years) on the LEDs must have been sleep deprived.!!
Nov 1st,2013 has marked the day of increase for the cost of electrical energy. The cost which includes the delivery charge, taxes, line loss, debit recovery charge etc. so the bottom line is $0.198/Kwh. before Nov 1st $0.17/Kwh
As we know cost will always increase so how is our return of investment now.
I believe I had calculated the ROI on $0.13/Kwh but I have to admit. I wasn't very careful and didn't put pencil to paper. The reasons I wanted to change to LED was, going on just the sizable power reduction (20watt to 6watt) and wouldn't have to change them out for 20 yrs.
As this price increase had me check back on my ROI and as like the stock market you need to be in long term??!!
Here are some numbers:
LED cost $6.00 MR-16 white LED 6 watt 12 volt. ( my home has about 40 of these on track lighting)
Cost saving:
20watt Hal - 6watt LED = 14watt reduction
14 watt x 4hrs/day average = 56 watt/day
56 watt= 0.056Kwh
0.056kwh x 365 days = 20.4 Kwh/year
20.4 Kwh x $0.13 (2009 price)= $2.65 savings per year per LED.
20.4 kwh x $0.198 (2013 price)=$4.04 savings per year
{$4.00/yr savings/light x 40 lights $160.00 per year savings} Who knew its a lot better than the Stock market!!!
Based on these figures ROI of late is 1.5 yrs. (getting shorter with every cost increase) and of coarse the approximate time for the duration of illumination of 4 hrs is just that. BUT still the cost savings are remarkable!!
Randen
