Can I get low energy low voltage bulbs?

[HappyFace]

I understand one of the easiest ways to reduce your electricity bills is to use low energy light bulbs in your home as they use around 75% to 80% less electricity than conventional light bulbs.
All over my house I have low voltage downlighters. Is it possible that these are causing my electricity bill to escalate? Is it possible to buy low energy low voltage bulbs?

[wildwood]

At the moment I don't think so. But the low voltage [12v. halogen, I presume] you are using now are quite energy efficient.