Average 'geek' home power drain?
February 3, 2008 5:36 AM   Subscribe

How large is the phantom power drain in an 'average' home? Thinking about installing a small solar power system on our house. The idea would be to cover the phantom power drain from appliances - as a small but meaningful step. I'd envision something that would cover the drain of random crud running all the time, wallwarts + tivo + wireless modem + refridgerator + a small ups + fios termination box. Trying to calculate a number that seems reasonable for those items. (Note: leaving heating out of this...)

I don't think this will pay for itself (we have municipal electric in my town & electricity is cheap), but it is an interesting project...

Anyone have experience with whole house energy meters?
posted by geekP1ng to Technology (32 answers total) 2 users marked this as a favorite
Stupid question, but... don't you have a meter on your supply?
posted by Leon at 5:56 AM on February 3, 2008

Buy a Kill-O-Watt and plug your electronics into it.
posted by schwa at 6:03 AM on February 3, 2008 [1 favorite]

Ah, just followed your whole house link.

So yeah, I bought one. It is kind of inconvenient to use - you can only plug one device (or power strip) into it then you have to leave it a few days to get some idea of typical power usage. Doing an energy audit of the entire house would be a pain.

But it gives you a great idea of where your electricity is going.

I used to have a Mac Pro and two monitors and peripherals (external HD, USB hub, etc) all hooked up and switched on with sleep mode turned off (the Mac Pro was also a server). While it doesn't take a genius to realise that all that was consuming a fair amount of electricity the Kill-O-Watt put it into perspective (as a % of monthly bill). The savings I've made have more than paid for the Kill-O-Watt.
posted by schwa at 6:09 AM on February 3, 2008

Calculating the phantom load is easy enough using your standard electric meter. Plan an overnight trip somewhere. Take a reading of your utility company's electric meter when you leave, noting the time. Leave everything running that you consider to be "phantom" load (personally, I don't think the fridge is part of that, but include it if you want to). Most of it is not going to draw a different load with or without you in the house. Come back at least 24 hours later, read meter again. If you can't do an overnight, at least stay out of the house all day and take a 12-hour reading. Divide KWH usage during that period by the hours you were away. The result is your phantom drain, in kilowatts. You could increase it by some amount to cover the fact that when you're around, the fridge opens and closes a few times which increases the load, but really, that's active usage, not phantom. (If not familiar with reading the meter: if it's the normal mechanical kind with dials, remember that the dials for the digits read alternately clockwise and counterclockwise).
posted by beagle at 6:24 AM on February 3, 2008 [1 favorite]

By the way, it's an interesting question -- it occurred to me a while ago that when I was growing up in Europe in the 50s (without a TV or refrigerator in the house), the complete list of electrical devices in the house, besides light bulbs, was: vacuum cleaner, radio (one), cooking stove, coffee percolator and washing machine (no dryer). No such thing as phantom load there.
posted by beagle at 6:30 AM on February 3, 2008

Going a little further with beagle's answer, I once did this without the overnight trip by calculating how many watts were represented by individual notches on the mechanical wheel in our meter. I'm sure the error rate is a bit larger with this method, but it's quicker and gets you fairly good answers.

My goal at the time was to determine the different power usages of each of four people living in a shared residence. One particular user had several computers always on, and was famous for leaving every light he touched on. So, we turned off everything in the house, checked that the meter had stopped, then began turning everything related to one person back on, then checked the meter again.
posted by odinsdream at 7:03 AM on February 3, 2008 [1 favorite]

If I understand you, you want to power your refrigerator with a small solar array. Unless your fridge is a super-small, super-efficient unit like those sold to people who live off the grid, that won't be possible. A refrigerator is a notorious energy-gobbler.

That's not implying that a solar array is a bad idea or won't offset some of the energy used by the fridge. But you might consider putting some of that solar panel money into a super-efficient fridge, like one of the small Energy Star models or, if you're feeling wealthy, a SunFrost.
posted by PatoPata at 7:51 AM on February 3, 2008 [1 favorite]

I am also curious about your physical setup. Have you planned how this solar panel is going to be integrated into your current electrical system?
posted by odinsdream at 8:07 AM on February 3, 2008 [1 favorite]

Many modern solar power systems for homes don't have any batteries at all and you can think of them as operating in two modes. If the system is producing less power than your house is using the different is made up by the utility and your meter runs forward. If the system is producing more than than your house is using the excess is fed back into the utility and your meter runs backward.

There are two things to consider here. First, such a setup could be built using a very small solar array with the intent of adding on to it over time. You'd end up buying a somewhat oversized converter and controller for your initial array, in other words. This would keep the initial cost somewhat low. Second, consider that all power used counts equally. In other words, taking a 10 kW-hr bite out of your air conditioner or big screen TV counts just as much as taking a 10 kW-hr bite out of a bunch of smaller loads. Thus it may not be worth trying to separate them.
posted by LastOfHisKind at 8:26 AM on February 3, 2008 [1 favorite]

Here's the data for average phantom loads.
posted by glibhamdreck at 10:07 AM on February 3, 2008 [2 favorites]

My guess is that the fridge is consuming several orders of magnitude more power than everything else you mention combined. You might want to remove it from your calculation.

Heck, if you really want to live efficiently, figure out some lifestyle changes that would allow you to turn off the fridge for good.
posted by ikkyu2 at 10:23 AM on February 3, 2008 [1 favorite]

Maybe I could, but the wife is not going to be happy about no fridge :-) I can just see that coming like a freight train!
posted by geekP1ng at 10:27 AM on February 3, 2008

odinsdream / lastofhiskind - you guys even out. I think an oversized converter, and a relatively small PV setup. What I worry about is our municipal power co., am I right that not all states allow meters to run backwards?

BTW we do have an Energy Star Fridge - though marriage dictates it is larger than we absolutely need ;-)
posted by geekP1ng at 10:35 AM on February 3, 2008

lastofhiskind - re separating out usage, true there is no difference between energy used for one purpose or another - from a dollars standpoint. When it comes down to karma, its a different issue, its all related by motivation and intent. (And no, I'm not trying to make this a spiritual discussion.)

I'm thinking it would be cool if everyone did a small part. So "phantom power load" is my first take on "small"... And yes I agree that the fridge isn't normally what would be called a phantom load...

I'm going to try reading the meter (before MiLady gets back from shopping)...
posted by geekP1ng at 10:42 AM on February 3, 2008

I dont understand what youre doing here.

1. Solar panels take anywhere from 4-20 years to payback the energy it takes to make them. So youre just burning more coal by putting this thing up.

2. Its not all great for the environment to have industry making panels people dont need.

3. The previous two assume no battery system, which would make the numbers and environmental situation much worse.

What you need is a timer for all your toys. At midnight or whenever you go to sleep have it shut off ALL power until 6am. So long standby drain!

Also its worth noting that a tivo isnt a phantom drain, its on 24/7 trying to record your shows and downloading schedule updates. "Standby mode" on a tivo is just shutting off the video outputs, this is nothing in terms of power. You should attach your tivo to the timer I mentioned and just have it cold boot every morning. Leaving a tivo on is like leaving an old PC on 24/7. No solar panel is going to make up for that.
posted by damn dirty ape at 10:45 AM on February 3, 2008

Watt usage:

series 2 tivo: 40
modern efficient fridge: 70-150
posted by damn dirty ape at 10:47 AM on February 3, 2008

So it looks like .331 KWH with the fridge plugged in (3.7 cents per hour, $330/yr)
.183 KWH without the fridge plugged in (about 2 cents per hour, $182.43/yr)
posted by geekP1ng at 11:02 AM on February 3, 2008

DDA -- no batteries. The power never goes out here. And this will only work out if the local utility allows us to feed power back into the grid.
posted by geekP1ng at 11:15 AM on February 3, 2008

One of the phantom drains is the X10 timer itself. Ironic.
So Gaiam has a 208 Watt panel... for $1,179, and an inverter for $2,460...
posted by geekP1ng at 11:27 AM on February 3, 2008

Youre not feeding power back without timers. Your tivo alone is going to outdo any affordable cheap hobbyist PV wattage. Thats also ignoring all the energy it takes to make and ship a panel. If you want to do this for fun, thats great, but youre not really doing it for the environment or to lower energy usage without moving towards a high effeciency chest fridge and putting everything on timers to stop standby drain.

This panel will fight off the drain by owning a tivo. Its 300+ dollars. Now toss in installation and wiring, etc etc. I'm sure youre looking at 500 to 600 dollars. Digital plug in timer 19.95. Or is that not 'geek' enough for you?

Dunno what yorue planning but doing this stuff without addressing the high wattage devices is being pretty silly. I'd worry first about getting your wattage level as low as possible and then start thinking solar.
posted by damn dirty ape at 11:27 AM on February 3, 2008

One of the phantom drains is the X10 timer itself. Ironic.

Electrical devices need power. There's nothing ironic about that. If its saving you 300+ watts and its using 3, then whats the problem? They dont run on magic and positive thinking.
posted by damn dirty ape at 11:30 AM on February 3, 2008

No need to get snarky about it.
You may have a good point about the energy cost of making PVs, but I am waiting for references.
posted by geekP1ng at 12:03 PM on February 3, 2008

You could skip solar and generate power with a stationary bike.

Here, previously.
posted by beagle at 12:43 PM on February 3, 2008 [1 favorite]

WRT the energy cost of PV: I think Don Lancaster's Energy Fundamentals pdf covers it pretty clearly, with a medium math level.
The only time I've seen a net energy accounting where current PV arrays come out positive is when they do the calculation assuming that all feedstock is semiconductor fab waste, or some other source of ultra-high grade refined silicon - Which is (IMO) misleading, and leads to bad decisions by good-intentioned people: If only (X) pounds/year of solar cells can be made at below-net-energy, wouldn't we be better off leaving them for the people who need solar cells for their application, and using less-net-energy for our purposes by plugging into an outlet where it's available?
This is leaving out the whole 'Purchases create demand, which drives research, which will mean it's better in the future' argument, of course. I think it's a safe guess that everybody who's qualified(*) to develop a brand new source of clean energy is probably working on it right this minute, California Gold Rush Style.

(* - And then some. No shortage of At Home players in this field.)
posted by Orb2069 at 1:19 PM on February 3, 2008

Good thought! Now if I can just run a cable to the gym, we'd be entirely wife powered! Lets say she generates 400 calories in 30 minutes. Thats 800 calories an hour.

1 KWh = 8.598 * 105 Calories... So 800 / 859800 = .00093 KWh. Not going to be powering much there. (We'd do better if we could capture the waste heat!)

I suppose we'd save more than that by skipping the drive to the gym and working out at home. Hmmm... Say she burns .0666 gallon of gas, 125,000 BTU * .0666 = 8325 BTUs / 3413 BTUs per KWH or 2.4 KWh.

So we spend vastly more in energy driving to the gym than we expend working out. I suppose I knew that, somehow... Darned baby-boomers ruining the planet for everyone else...
posted by geekP1ng at 2:01 PM on February 3, 2008

I respect your intentions. However, buying something new to solve a problem is usually less efficient than removing the problem. Shrinking your energy footprint would likely be more energy-efficient and inexpensive than buying solar panels.

I'm a geek luddite living in a super-efficient house on the grid. I'm a woman, and I don't agree with the common assumption that women require comforts like oversized refrigerators. If your wife has concerns along those lines, she's welcome to send me a message.

A few ideas:

Stop watching TV. Extremely effective.

Dry your clothes on a line outside. In winter, hang your clothes on a line in the bedroom. That way, you can ditch the humidifier as well.

Plug all computer stuff, including the printer and scanner, into a power strip with a switch. Turn it off when you go to bed.

If you have a fax, replace it with MaxEmail or some other online fax service.

Put a little in-line switch on the power cord of things like your stereo. It's cheaper than a power strip, uses fewer materials, and is simple to install on most cords.

Don't use powered gizmos for things you can do under your own power (slice, dice, commute).

Compact fluourescent lightbulbs, yada yada....
posted by PatoPata at 4:02 PM on February 3, 2008

Thanks for the conservation reminder...

Not meaning to offend anyone with my sexist remarks about my wife. She really did want a larger fridge :-) but we still have a kitchen from the 40's... With a more efficient fridge.
We want a newer kitchen too - but want and need do not coincide in this case.

The smaller high efficiency fridges (Sunfrost etc) did not have a realistic payback with our local energy costs.
posted by geekP1ng at 8:04 PM on February 3, 2008

Just to question the assumption that fridges are such power hogs. I just looked on our bog standard family sized fridge/freezer (Westinghouse RJ522) and it specifies it uses 508kWh per annum, scoring 4.5stars from a possible 6 on the government score.
Power here is in the order of $0.15 per kWh so about $76 p.a.
Our power bill shows us using 14kWh per day. We cook and heat and heat water with gas and have no A/C.
posted by bystander at 8:44 PM on February 3, 2008

Orb2069: I think you have it backwards - until very recently, all solar panels were semi conductor fab waste. And even today, I think you'd have difficulty finding any (silicon) PVs that weren't. As far as I know (and I haven't bothered to look further), the world's first factory for non-waste PV only opened last year. I have a wide range of PV cells from many sources, and I don't think any of them are anything but re-used fab-waste. So I think it's quite fair to consider (installed) PVs as net source of energy considering their construction energy was going to be spent making that waste anyway. (Thought under or unused PV is, of course, going to create an energy sink).
posted by -harlequin- at 4:15 AM on February 4, 2008

bystander: So I was seeing about .330 kWh constant usage without lighting, TV, computers, hair dryer, irons, etc. That works out to 7.92 kWh daily

Some interesting comments on the Don Lancaster article here (see comments at bottom)

He's probably right about much of what he says, but he doesn't give references so the reader can check his assumptions. The economic arguments strike me as tenuous. He's right on about the principles of thermodynamics, but we all agree on that point. A mixed bag. It appears that his fears regarding the supply of silicon never materialized.
posted by geekP1ng at 9:06 AM on February 4, 2008

A couple well written blogs re: photovoltaics, by Robert MacLeod

1) trends in capacity
2) environmental costs of PVs

From this reading, it appears that processed silicon supply issues have arrived, but that new thin film techniques and new production capacity have largely mitigated the supply issue. MacLeod stives to debunk the 'urban myth' that PVs are a net energy sink / or generate greater carbon output than conventional power systems.
posted by geekP1ng at 3:46 PM on February 4, 2008

Spoke with Real Goods tech about all this. To cover a 24x7 300 Watt load, I'd have to generate 7.2 kWh / day. Over a year we average 4.6 hours daily of full sun here. So I'd need to size an array about 1.5 kWh.

6 - 300 Watt solar panels, plus an 1800Watt inverter. Something like $6000 materials plus labor, say $1,500. There is a tax credit of $1,000. So the outlay is $6,500. This would save me $300/yr at 0.1108 per kWh, with a 21 year return. Not quite baked yet, I guess...
posted by geekP1ng at 7:09 PM on February 4, 2008

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