Lighting

If I were to build a new house I would insist that all light would be Led lights running on 12 volts from a battery pack powered by a small solar pannel. Cost savings would be about 11% of the total bill. say about 20 dollars a quarter. The cost of these lights is about ten dollars each the solar pannel is for 40 dollars and the batteries would be say 100 dollars. Eight lights  one battery pack and solar pannel and wiring would cost in the vacinity of say $500 This would give a pay back 500 devided by 20 times four which would equal 6.25 years. But it would cost similar amounts to install 240 volt system. Then there is the 12 volt system can be installed by anyone whom has the ability, against the electric trades person at trades wages.
The there is the fact that the middle bulb below has high amounts of toxic materials inside.