🚀 go-pugleaf

salman@sungear.mame.mu.OZ.AU (Salman SHAMI) writes:
>I like to leave my TV and VCR in standby mode. My CD player amp and tuner
>switched on. 

>How much power does each piece of equipment use when left switched on as
>described above ? 
>Does it make any difference if the volume of the amp is turned
>up or down ?

Others have posted conflicting numbers.  I gave some numbers before,
but I did not remember the numbers exactly, so
I re-tested the power consumption of the stereo equipment I had tested
before, and tested a TV.  I didn't test a VCR, since my housemate was 
concerned about losing his programming.  Here are the results:
 
                           Power consumption when:
Item               Age  | Plugged in   | Plugged in  | Plugged in      |   
                        | Pow. Sw. off | Pow. sw. on | Pow. sw. on     |
                        |              | Idle        | Actively playing|
 
                          "STANDBY"     "IDLE"         "ACTIVE"
 
TV, RCA, 21"       <1yr   3.0W           N/A            50-80W*
Receiver, Sony,    ~2yr   2.2W           37.5W          45-60W**
Receiver, Sony,    ~10yr    0W           31.2W          32-40W**
CD player, Sony
 5 disc carousel   ~2yr   3.5W           8.0W           10 W
CD player, Sony
 1 disc            ~7yr     0W           8.9W           11.4W
Cassette Deck,
Harmon-Kardon      ~10yr    0W           11W            15W
 
*Depended on brightness control setting, and content of picture.
 I don't know the consumption displaying black (idle), since the control
 did not go down to zero.
 
**Depended on how loud it was playing.  (Setting of volume knob did
  not matter with no signal coming in.  Signal coming in did not matter
  with volume set to zero.)  The numbers I got reflect the usual range of
  volume levels I listen at, and depended on things like the efficiency of 
  my speakers and room sizes, as well as my volume preferences, but I
  included them to give a general idea.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
What does all this mean?  Well, as I said before, a watt of idle 
power is like a buck a year.  The TV needs 3W to keep the cathode
hot so it will come on instantly.  It would be nice if they gave
you a switch to disable that feature if you are not impatient.  
But that would cost them an extra 25 cents, and they wouldn't want to  
up the price of the TV by a dollar just because that would save you 
20 dollars over the life of the set.  So you are stuck buying a power 
strip with a switch, or something like that that is much more expensive,
but would still pay for itself.    ($10 pays for itself in 3.3 years)
Note that if this TV is on 1 hour per day, the standby power uses more
energy than the actual operation.
Note also that the power consumption during actual operation could also
be lower, but the manufacturer probably doesn't care about that either.
 
As far as audio equipment, the receiver uses a lot of power when on
and idle, so it is clearly worth turning off.  If you plug all your other
audio equipment into the back of the receiver, it will disconnect them
when it is off, and so they will use zero power.  The only thing left is
the standby power of the receiver.  In my old one this is zero--the power
switch disconnects the power.  In the new one, however, they decided to
make the remote control able to turn on the power.  In order for this
to work, the IR (remote contorl) receiver circuitry needs to be 
operational.  The circuitry itself probably only requires a few 
tens of milliwatts.  But they get this power from a cheap 60Hz 
transfomer that has losses of about 2W.  It would be nice if
they let you disable this, or better yet, used a more efficient
power supply for the remote control receiver.  Again, a power strip
will (unles you pay an outrageous price for it) pay for itself.
 
The standby power consumption of other components is not a problem 
if you plug them into the switched outlets in the back of the 
receiver (or the power strip that you just ran out and bought :-) ).
The idle power might be worth considering if you have the system on a lot
and have components that you don't use  (e.g. tape deck if you listen
to CDs)--just switch them off manually when they are not needed.
It is interesting that my old CD player uses no standby power, but
the new one does.  Both have remotes that do not include power on/off.
My guess is that the new one switches power after the 60Hz transformer,
and that transformer uses 3.5W unloaded.
 
Charlie Sullivan                          charless@power.berkeley.edu