In message . com,
KevinGPO writes
Can you advise me on the lowest-energy / energy-saving-light-bulb-like
bulbs that I can purchase for the socket type that I have. Or are the
bulbs am using the cheapest/lowest-energy I can use?

You could theoretically install 12V 20W lamps in the same style, but
depending on the type of transformer and the loading, the voltage may
rise slightly. If it's 11.5V to start with then that may not be much of
an issue. Have you any idea if it's a separate transformer per light or
if there's a common transformer?

Another option would be to install the LED version of the lamp, but
their output is very low and the white tends to be rather harsh.

--
Clive Mitchell
http://www.bigclive.com