How power efficient is using a bluetooth stereo headset (with it's own battery obviously) compared to the regular wired headset being powered by the device itself? Is streaming audio over bluetooth more power consuming than powering a wired headset?

Well, with bt headset you need to activate bt on the phone, so more power consumption

In my experience bluetooth is very power consuming, and unfortunately a little quirky. You need to remember that bluetooth uses a transmitter / receiver within the device that requires constant power.

Additionally, the common experience seems to be that maintaining a paired connection with a device after phonecalls and other interruptions is sub-optimal at best. personally I'd find that after a call (or sometimes quite randomly between starting and stopping music playback) sound would come out from the speakers rather than BT or I'd need to disconnect and reconnect the device several times to get it working correctly again. I also found that my headset battery would drain much faster than it should when not in use (but paired) which I suspect is also because of some driver / hardware problems with the N900.

Because of this I now leave BT permanently turned off and get much better battery life. A shame as I have always liked the sound of my SE HBH-IS800 headset.

Thanks for the replies so far.

Anyone else with similar/different experiences, or generally more info on this subject?

Bluetooth uses more power by several orders of magnitude. There is no two ways about it.

I use a plantronics backbeat headset, and only enable bluetooth when I'm using it because BT indeed drains the abttery. And if you keep the n900 in the wrong pocket the audio can sometimes drop for a very short time.

But other than that, I love it. pairing is no issue at all, music is interrupted nicely when a call comes in, and resumes afterwards. The headset battery goes for several hours.

one more thing to keep in mind is that keeping bluetooth visible requires more power than to have it hidden, I believe.

It's the phone battery life that I'm worried about; i burn through it quickly enough, so it would be a great problem for me if streaming music over bluetooth to a wireless headset was to use a few times more power than the regular wired headset...