How Much Power Do LED Drivers Draw When Not Loaded?
12V constant-current power supplies have a small &quot;standby&quot; power usage of a watt or three depending on quality, when all the DC loads are switched off.  You can measure this by plugging it into a Kill-a-Watt. Other than that, they draw whatever power is used on the DC side, plus a few percent for conversion losses.
12V LED strips typically use a constant-voltage power supply, which is simply called a power supply. They are often marketed as &quot;drivers&quot; because it sounds cooler, but that's wrong.  Any 12V power supply will work for LED strips.
(a real driver is a constant-current source and must be custom-matched to a very particular array of raw LEDs. LED strips don't work that way).