saleem145 said:
Hello,
How do these manufacturers know that there LEDs will last 20 years??
Do the energy savings warrant the higher cost?
Saleem
Saleem, LEDs have been around since the 1950s (Bell labs, I think). The transister is from roughly the same vintage. An AC LED lamp has electronics inside to convert the 120V AC to the direct current the LEDs need. The LED's themselves will last a very long time. The electronics in a quality lamp should also.
Bottom line - there's not much 'new tech' in LED lamps - it's just that the price to build the device is finally come down enough. All the bits inside have very long track records.
edit...gack - I see Doxy and Ingineer already covered this. Sorry.
saleem145 said:
Do the energy savings warrant the higher cost?
Yes. Start replacing the most used lamps in the house. You might not replace the lamps in closets until they burn out because they're not used enough to show an energy savings. But replacing the rest will save money. Here's an example from my office:
I have a ceiling fan that holds four bulbs. I used four 60W incandescents initially. The lights are used about 13 hours per day 7 days a week. My electricity is about $0.135 per kWh.
Incandescent: 4x60W=240Wx13 hours= 3120 Wh or 3.12 kWh per day x 365 = 1138.8 kWh per year x $0.135 = $153.74 per year
LED (Philips L-prize 60W equiv.): 4x10W=40Wx13 hours= 520 Wh or 0.520 kWh per day x 365 = 189.8 kWh per year x $0.135 = $25.62 per year
LED savings annually: 153.74-25.62 = $128.12
Cost of bulbs: $35 each x 4= $140
If electricity prices stay the same, the lamps will pay for themselves in 13 months.