First, the range of quality in light bulbs is enormous. Make sure you are buying bulbs with the brand of a long established company with a reputation to uphold. Everything is made in China, but some things are made with an eye to quality control and some aren’t.
Second, make sure your electrical system is up to snuff. In the apartment we lived in before we bought our house, CFLs lasted a year or two at most. The apartment had insane electrical issues, like two outlets on the opposite sides of the building in completely different rooms being on the same circuit. In our current house, which was completely rewired by a professional before we moved in, I am only now starting to need to replace CFLs that I bought seven or eight years ago.
Third, heat shortens the lifespan of bulbs. If you have enclosed or semi enclosed fixtures like potlights, make sure you buy bulbs that are rated for enclosed fixtures.
Let’s say we are going to run a 24V system. With a basic setup you could do a 7 LED setup and a resistor for current control. Average efficiency is around 100 lumen per watt, so for a 700 lumen light that’d be 7 watts. Now in my kitchen I have 6 lights like this. So at 24V, 6 lights, 7W…that’s a current draw of 1.75A. A 200 foot run a 14 gauge wire provides roughly 0.5 ohm of resistance. This leads to a 1.55W loss of power in the wire. While at 120V you’d only see a loss of 0.06W. (Not to mention if you rectified it and were dealing with 170VDC.)
While that 1.55W loss isn’t much and neither is the 1.75A, but that is just on one lighting circuit. I know there are times where I have 15 individual lights on.
You are right about this. The only problem with 120 VAC is that every lamp needs it’s own rectifier and capacitor, and typically power supplies integrated into lamps are engineered to fail soon. The best solution would be with voltage around 120-300V but rectified and stabilised.
I think a better solution would be a standardized bulb base per voltage/current design with a dedicated switch mode power supply for each lighting area or circuit. If you had an SMPS box that could do 100W and be enclosed in a single gang box (double would work, but you might need to have it located somewhere besides the switch box). Make it standardized, plug and play, and I don’t see why you couldn’t get years out of it. My PC stays on practically 24/7 and has been on for over 5 years. I’ve seen some under cabinet lighting done like this and I think it would work well.
