I have my Kill-a-watt...now what?

[ldjessee]

Hello,

I got a Kill-A-Watt for my birthday and I am trying to figure out where to use it first. Any suggestions?

[Daox]

I highly suggest you start with your TV/DVD/etc home entertainment stuff. Thats the stuff that usually sucks a lot of power even while they are "off" or in standby.

[ldjessee]

Yes, we have two TVs we watch. A Tube upstairs and a HD set downstairs, with surround sound.

I think the tube and the surround sound amp are the two that will be consuming the most power.

Maybe I convince the wife to replace the tube with another LCD.

Not sure if they make amps that use less power but still sound decent.

[Daox]

I'm staying test your stuff when it is in the off or standby mode. If you find that they are pulling a lot of power while they are off, you can put those things on a separate power strip (or smart power strip) and turn it off when its not being used.

[insaneintenti0n]

surround sound doesn't take nearly as much as you'd think it would. in standby, my power hog was my DVR. everything on... of course the TV

[maxcooper]

Here are some areas where I found some potential savings for audio/video things that are ON:

* adjust the backlight level on your LCD TV (watch how much the power consumption changes on the Kill-A-Watt as you do this)

* if your surround sound receiver has a setting for speaker impedance (measured in ohms), it will likely use less power on the "low ohms" (usually 4 or 6 ohms, depending on the receiver) setting. However, it will also deliver less power to the speakers. The "low ohms" setting is probably fine for watching TV, but you'll most likely want to switch back to the "high ohms" (usually 6 or 8 ohms) setting for watching movies, listening to music at moderate to high volume, etc. This may not be worth the savings, but if you are trying to save every last kW it can help -- it will also keep the room cooler, which is nice for casual TV watching in summer.

Some tips for reducing energy usage of AV stuff while it is OFF:

* This isn't really a tip, but DVRs use a lot of power (50-100 watts) even when they are "off". There usually isn't much you can do about this.

* Measure your subwoofer. Unless you manually flip a switch to turn it on, it probably uses 10-25 watts when it is "off". You can automagically cut the power to the sub when the stereo is off by using a "smart power strip" (like the SCG3, 4, or 5 -- amazon has them all, and the 3 is not always the cheapest one). Plug your receiver into the control outlet, and plug the sub into a switched outlet. That will reduce the power usage of the sub to 0 when it is "off" with no change in convenience (it will turn on automatically). However, some subs do make a noise when they turn on or off using this method -- my sub does, but I can live with it. Fancy home theater power centers can do switching like this, too.

* Measure your receiver in the OFF/STANDBY state with the Kill-A-Watt. If it uses more than a few watts, try some settings changes or search the web for your receiver model for settings changes that will reduce the power usage. As an example, my receiver (Onkyo 805) uses about 2 watts in standby mode, but that shoots up to 70 watts in standby mode if you turn on the HDMI Control feature.

-Max

[NiHaoMike]

One easy trick to reduce standby power use of an old tube TV or monitor is to disconnect the degauss coil. Then manually degauss it by rotating a moderately powerful magnet (should stick well to a steel object but not take excessive force to remove) while slowly backing away from the screen.

This isn't really a tip, but DVRs use a lot of power (50-100 watts) even when they are "off". There usually isn't much you can do about this.

Install a hardware power switch. Although my Samsung DVR only uses 9w (operating or not) and my Panasonic DVD recorder in standby uses too little to read on a Kill-a-Watt after I rewired the Nixie tube supply to only turn on when the recorder is on...

Measure your subwoofer. Unless you manually flip a switch to turn it on, it probably uses 10-25 watts when it is "off". You can automagically cut the power to the sub when the stereo is off by using a "smart power strip" (like the SCG3, 4, or 5 -- amazon has them all, and the 3 is not always the cheapest one). Plug your receiver into the control outlet, and plug the sub into a switched outlet. That will reduce the power usage of the sub to 0 when it is "off" with no change in convenience (it will turn on automatically). However, some subs do make a noise when they turn on or off using this method -- my sub does, but I can live with it. Fancy home theater power centers can do switching like this, too.

Buy some used large speakers, get improved sound quality, and do away with the subwoofer. A pair of used 12" 3 ways from Salvation Army cost only $40 a pair (I also have a pair of 12" 2 ways for $20 and a pair of 4" 2 ways for $5) and go surprisingly well with a TI hybrid digital amplifier.

Measure your receiver in the OFF/STANDBY state with the Kill-A-Watt. If it uses more than a few watts, try some settings changes or search the web for your receiver model for settings changes that will reduce the power usage. As an example, my receiver (Onkyo 805) uses about 2 watts in standby mode, but that shoots up to 70 watts in standby mode if you turn on the HDMI Control feature.

I wonder how it's using 70w in standby. Does it have a PC-like computer in it that stays running if the control feature is on? I'm thinking the GPU for the HDMI is left running, but I don't know why they would put something that runs so hot into an amplifier. It's definitely bad engineering. For comparison, my old 64-bit PC uses only about 80w when idling without PMS (Power Management System). With CPU frequency management, it goes down to 65w or less. (That includes the motherboard, CPU, hard drive, video card, sound card, digital TV receiver, IEEE1394, an extra network card, 2 optical drives, and some USB peripherals.) At least standby without control is much lower, but it's still twice what my homemade TI hybrid digital uses when *operating*.
http://ecorenovator.org/forum/applia...ome-audio.html
Which means that my old desktop computer (not originally designed for high efficiency, even!) and TI hybrid digital amplifier combined use less power than that amplifier when left idling. Or if I use my laptop (15w idling, 18-20w during typical use, 40-60w during intensive load), it would together use less than 1/3 the power! That 70w of waste in standby is quite a shame for something from a country that is supposed to be well known for high efficiency...

[maxcooper]

Originally Posted by NiHaoMike

Install a hardware power switch.

That won't work for the way folks generally use DVRs, as it won't record anything when the switch is off.

Originally Posted by NiHaoMike

Buy some used large speakers, get improved sound quality, and do away with the subwoofer.

You need a sub to hear the ".1" LFE track from movies -- a receiver will not play this content on the main speakers. Room placement and LF extension are two more reasons why big main speakers are not a perfect replacement for a subwoofer.

Originally Posted by NiHaoMike

my homemade TI hybrid digital uses when *operating*.
http://ecorenovator.org/forum/applia...ome-audio.html

That's cool! Nice work.

I have some Panasonic receivers that use TI's "digital amp" modules. They are relatively efficient as receivers go, but still use 25+ watts when on and not playing anything.

Originally Posted by NiHaoMike

Which means that my old desktop computer (not originally designed for high efficiency, even!) and TI hybrid digital amplifier combined use less power than that amplifier when left idling.

You'll be appalled when I tell you that it uses 125 watts when on and not doing anything. It drops a bit to ~90 watts if you switch the speaker setting to "4 ohms" (which still works fine with 8 ohm speakers, but just limits the power output a bit). The Onkyo 805 isn't efficient from an energy usage perspective, but it is a gem in other ways so I won't be getting rid of it anytime soon. And the standby power isn't out of line as long as the HDMI Control feature is off (and I have no use for that feature anyway).

-Max