Hello All,
A month or so back, there was an article on A Current Affair about a company called Neco (I just saw it and have no relationship with them), and decided to dig a bit deeper.
They do the in home assesment of lighting, eco freindly water and stuff. One of their big things is to convert all lights in the house to fluro bulbs. They sell fluro downlight compatible bulbs that attach to a 240v direct line.
http://www.neco.com.au/product.asp?pID=95&cID=47
They also suggest as others have here that low voltage does not actually save you anything as power dissipates through heat on the transformer.
The resolution, throw away the transformer, convert your enclosures to 240V with one of their conversion kits and add their 7W GU10 Megaman downlight bulb.
There is an energy calculator (don't know how accurate this is) which gives the representaiton of the savings. EG I just purchased 10 x 12v halogens on e-bay for the kitchen reno, cost me $100. To run them - apparently $159 for the year. After conversion kit and bulbs which would be worth $280, the power bill drops to $27. Seems fairly remarkable, but would take just over 2 years to recoup the investment.
The other thing they mentioned on the TV was in NSW, the gov was handing out all sorts of rebates to green up houses. Neco will come and do the assesment presumably to sell you plenty of kit, but through rebates scheme would give you a house full of fluro light bulbs and water saving shower head for free.
http://www.neco.com.au/product.asp?pID=164&cID=97
Anyway, I thought it was slick marketing, but it gets you thinking. As the edison screws have blown up at my place, I have progressively replaced with fluro bulbs. Mrs 11 prefers the light so everyone's happy.
Cheers....DC :)