Thanks for asking. I simple look at the current draw from my powersupply. The current is measured with no hdmi attached. With the original Raspberry Pi model A, the current draw looked like this:
Raspberry Pi model A: 70mA
Others circuits: 30mA
With the new Raspberry Pi model A+, the current draw looks like this:
Raspberry Pi model A+: 120mA
Other circuits: 30mA
This results in an increase of 50% in total
My power supply delever approx 13Volts (simulating car battery voltage drop), whitch are switched down to 5Volts.
Well, I have noticed that, with the HDMI cable plugged in, the current draw in total is:
Usings Raspberry Pi model A: approx. 280mA
Usings Raspberry Pi model A+: appox. 250mA
It seems, that you gain some efficiency with the hdmi plugged in, but looses it with no hdmi. The power consumption difference is less on the A+. However, I have hoped the power consumtion, at least would have been the same, with no hdmi plugged in, as this would be the case in must of all aplications.
Best Regards Allan