US introduces $60 LED light bulb (BBC)

[longship]

11. Standards would help here

For instance, all power supplies in most electronics today require +- 5 volts and +- 12 volts. (+- means both positive and negative voltages might be required). Digital circuits almost always require only +5V.

If I were designing an energy efficient house, I would centralize rectification at the point AC power comes into the house, and distribute the power to the various devices, lights, etc. I would bet that if one could reduce losses there would be significant savings.

Unfortunately, try to buy a computer, TV, refridgerator, air conditioning, or other appliance that ran on DC. There would have to be cooperation by manufacturers. I could build a computer that did this, but if one went without some of the other things -- the fridge and central heating would be a problem -- you could easily do it.