power consumption of automated light switches when OFF

[electron]

Has anyone done research on how much electricity automated switches use when turned OFF? I am especially interested in the difference between X10/Insteon/Z-wave and UPB.

 

[rfdesq]

I called PCS and their switches in do nothing mode draw about 1/4 watt.

 

[BrettS]

I called PCS and their switches in do nothing mode draw about 1/4 watt.

I hadn't considered this too much, but that's not totally insignificant. 60 switches at .25W is 15 Watts... 15W for 24 hours a day times 30 days is 10.8 KWH... I pay about 11 cents per KWH, so thats about $1.18 a month. It's not a huge cost, but my power bill last month was only about $90... so this is a bit more than 1 percent of it... That's assuming my X10 and ZWave switches draw about the same amount of power. Hmm... maybe I'll pull out the Kill-A-Watt tonight and see what I can find out about those switches.

Brett

 

[hucker]

I called PCS and their switches in do nothing mode draw about 1/4 watt.

I hadn't considered this too much, but that's not totally insignificant. 60 switches at .25W is 15 Watts... 15W for 24 hours a day times 30 days is 10.8 KWH... I pay about 11 cents per KWH, so thats about $1.18 a month. It's not a huge cost, but my power bill last month was only about $90... so this is a bit more than 1 percent of it... That's assuming my X10 and ZWave switches draw about the same amount of power. Hmm... maybe I'll pull out the Kill-A-Watt tonight and see what I can find out about those switches.

Brett

I'd be curious what they consume while lights are lit as well. I thought it would be cool if you could control the LED's on the UPB switches via UPB commands, have them off during the day and when nobody was home. Make them blink as an annunciator.... Just give me more control... :blink: I have bigger fish to fry than a buck a month....

 

[electron]

1/4W is not too bad. I wonder how the other switches compare.

 

[pkoslow]

I've got this little dimmer demo unit I made (see below), so it was easy to pull the airgap on the switches and test each one individually.

Insteon = .06A, 7.2 watts
Lutron RadioRA = 4.8 watts, 4.8 watts
HAI Gen II UPB = .06A, 7.2 watts
SAI UPB = .06A, 7.2W

I've got around 55 switches in my own place which burns around 396 watts continuously! That's about $65 monthly at my electric rate and about the same draw as my entire equipment rack... did I do my math correctly :blink:

I've thought about this for years, but never took 15mins to look into it.

Here's a photo of the contraption with the swithces:

Cheers,
Paul

 

[BrettS]

I've got around 55 switches in my own place which burns around 396 watts continuously! That's about $65 monthly at my electric rate and about the same draw as my entire equipment rack... did I do my math correctly :blink:

I think so if you're paying about 23 cents per KWH. Those numbers really surprise me, though... and I was thinking 1/4 of a watt was a bit high. I'm definitely going to be testing some of my switches later tonight.

Brett

 

[politics123]

I've got around 55 switches in my own place which burns around 396 watts continuously! That's about $65 monthly at my electric rate and about the same draw as my entire equipment rack... did I do my math correctly :blink:

I think so if you're paying about 23 cents per KWH. Those numbers really surprise me, though... and I was thinking 1/4 of a watt was a bit high. I'm definitely going to be testing some of my switches later tonight.

Brett

What are you using to measure consumption? I wired a switch to a plug to measure Leviton's Z-Wave devices, and I plugged it into a Kill A Watt. I was able to get some good readings, but the resolution of the K-A-W is only 1 VA. I left the device on for 24hrs to get a reasonable estimate of power consumed.

HOWEVER:
these devices are not solely passive. I measured the z-wave device without it being conneted to the network, but I'd bet it consumed more if its included in the mesh network and if there's a lot of traffic on it (it would broadcast more)

 

[Herdfan]

I've got this little dimmer demo unit I made (see below), so it was easy to pull the airgap on the switches and test each one individually.

Insteon = .06A, 7.2 watts
Lutron RadioRA = 4.8 watts, 4.8 watts
HAI Gen II UPB = .06A, 7.2 watts
SAI UPB = .06A, 7.2W

That seems way high. That much wattage (especially the 7.2's) would cause some lights to glow. I tried calling Lutron support but the queue was too long.

But using a wired Lutron Seetouch keypad with up to 8 LED's all of which are larger than the LED's on a RadioRA Maestro, the keypad requires the equivalent of 15 LED's of power. A 350 LED auxillary power supply provides 2A * 15V = 30 watts of power. So 30 watts can power 23 SeeTouch keypads or just .75 watts per keypad. There is no way a Maestro uses 6.3 times the power of a SeeTouch keypad.

A quarter of a watt seems about right for a switch.

Just being curious, I went into my Homeworks software and turned on a 65W recessed light to 1% via 600W dimmer. So in theory I put 6 watts of power through it and the glow was very noticible. There is no way the dimmers use that much power.

 

[BrettS]

What are you using to measure consumption? I wired a switch to a plug to measure Leviton's Z-Wave devices,
and I plugged it into a Kill A Watt. I was able to get some good readings, but the resolution of the K-A-W is only 1 VA. I left the device on for 24hrs to get a reasonable estimate of power consumed.

Here are my results. Note that my line voltage was exactly 120, which was quite convienent. Also, note that I used the calculation W= V*A*PF. The power factor on these switches was all very low, so even though I came up with a reasonably high VA number the actual number of watts was pretty low.

Switch				 A	  VA	PF   W

X10 Appliance Module  .01	1.2   .02   0.02
X10 Lamp Module	   .01	1.2   .02   0.02
ACT RS104			 .10   12.0   .05   0.6
ACT RD104			 .12   14.4   .06   0.9
ACT RD134			 .10   12.0   .10   1.2
ACT ZDW103			.04	4.8   .11   0.5

The measurements were done using my Kill-A-Watt meter, but I only took instentaneous measurements. Politics, do you have the numbers you got during your 24 hour test. I'd be interested to see how my instentaneous measurements compare to yours.

Brett

 

[pkoslow]

Gang,

I thought the numbers I came back were really high too!

I was in a hurry and typing fast, the RadioRA switch were .04A for 4.8watts... correcte below:

Insteon = .06A, 7.2 watts
Lutron RadioRA = .04 watts, 4.8 watts
HAI Gen II UPB = .06A, 7.2 watts
SAI UPB = .06A, 7.2W

I got the current reading by plugging the switches into a Kill-A-Watt meter. If I get some time this weekend I may try the experiment again with a proper meter.

Cheers,
Paul

 

[pkoslow]

I've got around 55 switches in my own place which burns around 396 watts continuously! That's about $65 monthly at my electric rate and about the same draw as my entire equipment rack... did I do my math correctly :blink:

I think so if you're paying about 23 cents per KWH. Those numbers really surprise me, though... and I was thinking 1/4 of a watt was a bit high. I'm definitely going to be testing some of my switches later tonight.

Brett

Brett,

Yeah, we've got some crazy tiers here in CA for electricity, but it boils down to around 22-23¢ KWH on avearage.

Paul

 

[BrettS]

Gang,

I thought the numbers I came back were really high too!

I suspect you may be forgetting about power factor. For non-resistive AC W=V*A*PF. From my measurements (see above) the power factor was pretty low, so I suspect that this may lower your wattage numbers quite a bit. You can get the PF measurement from your Kill-A-Watt also.

Brett

 

[felixrosbergen]

How about OnQ ALC switches? Anybody got an idea what they use?

I suppose they use a bit of AC and ofcourse you have to power to polling loop network (not sure if that polling is AC or DC).

Anybody have any thoughts on this?

 

[pkoslow]

Gang,

I thought the numbers I came back were really high too!

I suspect you may be forgetting about power factor. For non-resistive AC W=V*A*PF. From my measurements (see above) the power factor was pretty low, so I suspect that this may lower your wattage numbers quite a bit. You can get the PF measurement from your Kill-A-Watt also.

Brett

Power Factor... anything beyond ohm's law makes my head spin. :blink: