Home Electrical Energy Audit

[Bob_Roller]

My local electrical utility service provider (Salt River Project), has a program to let you borrow an electrical device ( Kill-A-Watt) for 30 days, to check out the electrical consumption, of general household appliances .

Got mine a few days ago, and it is surprising what some of the electrical  usage is on some of these appliances .

I got it mainly to check out the soon to be 16 year old refrigerator .

Probably wasn't the best time to check it, as the temperature is around 65 F. (18C) in the house .

But it only used 1.9 kwh in a 25 hour time period.


http://www.p3international/products/special/P4400/P4400-CE.html

[montmil]

Check your home for what's know as Electrical Vampires, too. No instrumentation needed.

What's an Electrical Vampire? They may include battery chargers for cell, cordless phones or tools left plugged in; TV, stereo, DVD and radio monitor lamps; Clocks on coffee pots, microwaves, stoves or other tech-y kitchen appliances; Computer hubs and sleeping terminals, printers, scanners; Other random electronic gadgets...  If you get bored some evening, turn off all interior lights and walk/stumble through your home while spotting all the small red, green, blue lamps glowing.

Is it sensible to unplug all these items? Not really. For example, who wants to reprogram that DVD player every time you record a program?

Also, most electric utilities have a base facility charge which you pay even if your home is totally dormant as to power usage. I note the utility raises this charge from time to time just to grab a few more bucks... since you're now buying energy efficient products and using fewer kwh. Oh well.

Monte

[Bob_Roller]

I put my audio/video components on power strips, when not in use, everything is unpowered .

Computer and it's accessories, are also on a power strip .

I have an electric water heater, and have it programmed for about 35 minutes a day in the winter months, and 10 minutes a day during the hot season .

I found one interesting item, the power supply for the door bell, was a 40 watt device, I replaced it with a low wattage power supply from I believe a cell phone, power usage now is 3 watts .

That 40 watts doesn't sound like a lot, until you calculate it's usage for a year, it comes out to around 350 kwh per year, just to power your door bell, a battery powered one is probably the most cost effective way to go !!

I've got what is called a 'smart' meter for an outside electric meter, the electric utility retrieves your meters info every day .

You can log onto the electrical utility website, and check your electrical consumption from day to day, and see how much you are using .

My calculated electric bill for this month is $60, this is for an all electric house .

[Barry]

I found one interesting item, the power supply for the door bell, was a 40 watt device,

Bob I had the same thoughts about a bell transformer wasting energy and although I haven't got around to measuring it yet in theory the 40W door bell transformer is not as bad as it seems. When it's in a no load condition the secondary winding of the transformer is open circuit (the bell push is not in use) it only consumes enough power to maintain the magnetic field in the core which will be a small fraction of 4OW. If it really did consume 40W the whole time it would get quite hot. I don't know for sure what the losses would be for a bell transformer but the 11,000/415V power distribution transformers I used to work with had losses of less than 2 %. The bell transformer losses will likely be more say around 5 - 10%.  Still that's 12.5 - 25 kWh a year so batteries might still be better. Other examples include shaving sockets which contain isolating transfomers.

Now I'm gonna have to go out in the cold garage and measure it.

[nhmaf]

Last year we bought energy star rated washer&dryer, and a new stove and refrigerator, too.   Our electric bill is about 15% lower each month.

With the influx of huge flat screen TVs, a new energy rating system for TVs is being rolled out (in the US, at least) over the next 3 years or so.  California is adopting the same scheme but on a faster timeframe, according to my IEEE journals.   At the center of the issue is that, even with the increased efficiency of the LCD and RGB televisions, their sheer size and complexity have increased the pwoer consumption to be as much or more than "normal" sized CRT-based televisions.  One of the innovative design changes that is coming back on the most energy efficient models - an honest to goodness, mechanical "On/Off" switch!!!!
 

[Bob_Roller]

Here's a sampling of the results I've seen so far .
36 inch Sony television, old technology, it's got a CRT, 121 watts .
Cable converter box, 13 watts in the 'OFF' position, 14 watts when it's on .
Microwave oven, 4 watts when not in use, 10 minutes of use on it's highest power setting, .20 kWh .
Stereo receiver 64 watts .
CD player 24 watts .
Phone with answering machine 4 watts .
Computer 141 watts .
LED alarm clock 2 watts .
60 watt CFL (compact fluorescent light)  18 watts .
150 watt CFL 44 watts .
Doorbell 3 watts .
Refrigerator (25 hour usage) 1.9 kWh .
Washing machine on it's longest wash cycle .25 kWh .
Coffeemaker 1 cycle .12 kWh .
Dishwasher on it's "pot scrubber' cycle (1 hour 35 minute cycle time) heats 3 gallons (11.5 l.) of water itself 1.1 kWh .
1 amp battery charger 13 watts .
Typical 'box fan', like you would use to cool your engine during a carb synchronization, 122 watts on high, 92 watts on medium, 64 watts on low .
Digital electronic timer for an electric water heater 4 watts .
Mechanical (electric clock mechanism) pool pump timer 36 watts .
Rainbow vacuum cleaner 850 watts .
Corded electric drill 240 watts .
Single 4 foot fluorescent light (mounted on my work bench) 46 watts .
1 hp air compressor 1,000 watts .

A few observations from my daily power usage .
Electric water heater 40 gallon (153 l.) 10 kWh per hour of actual heating the water .
Electric clothes dryer, 5 kWh per hour of usage .
.75 hp pool pump, .6 kWh per hour of usage .

[nhmaf]

That's alot of good data you've collected, Bob!

I know that the CFL bulbs have saved us a few bucks a month in electricity cost.   The do NOT however, work worth a damn as outdoor lighting in these cold northern climates though.   I've got to dig out that journal with the new power consumption limits for the energy efficient TVs - I seem to recall something like  85W or less for TVs under 46 inches.

[DeeG]

I know that the CFL bulbs have saved us a few bucks a month in electricity cost.   The do NOT however, work worth a damn as outdoor lighting in these cold northern climates though.  

Funny that they don't really mention that......  :-)   We stuck a CF in the well house over the summer.  It didn't work the first time I tried to turn it on when it was 23F out.  ~sigh~  Glad I brought my flashlight...  hehehe  

What they also fail to tell you is that you will not get the 'expected' life out of them if you only use them for a few seconds at a time (switch on, grab the book off the shelf, switch off).  I've noticed the ones in my bathroom take about 20-30 seconds to come to full brightness.

We're slowly swapping of all our CF's for LED's.   I only have three halogens left and those are in my sewing room, incandescents outside and in a couple of lamps inside (and the fridge).   All electric house here.  Dishwasher died about 5 years ago, never replaced it.  Bosch f/l washer, hardly ever use the dryer.  Winter time house temp is usually about 64F, gets down to about 54F at night, and I don't turn it on in the morning when I get up for work.  Haven't used the a/c in about 6 years.  

We only pay 2 cents a KwH here for electricity, so what we do really doesn't save a whole lot of money, but if we ever decide to sever that last tie to the public utility (phone excepted),  I can get by with a smaller generator.  

[Darwin_R65]

I purchased this device,
http://wattsclever.com/product/wireless-energy-monitor

connects to the cables coming off the meter, and measures the entire household load.

It's a wireless unit, that connects to the PC via USB. I can bring up graphs showing usage, which allows me to identify when we use the most. Usually on weekends arounds 8-9pm. Thats when we have most people in the house and the bedroom aircons come on for an hour or two.
Very enlightening.

John

[azcycle]

Another thing our local electric company offers is "off-peak" rates. If you do much of your high-energy consumption during off-peak hours, they give you a much lower rate.  A few times per year they send you a schedule showing when off-peak hours. So we typically make sure to run our heater/A/C, washer/dryer, etc during those times. It has really lowered our bill.

[darrylri]

We've got a big PV array and are on peak metering, too.  In the summer this works out especially well as the solar power drives our meter backwards at the peak rates.  

[montmil]

We've got a big PV array and are on peak metering, too.  In the summer this works out especially well as the solar power drives our meter backwards at the peak rates.  

Since you're actually sending power back to the utility company, do you get account credit for it?

[darrylri]

Sort of.  We get a monthly statement of accounts, and we "true up" each year on the anniversary date of our system.  However, if we're ahead at the end of the year, we have in effect donated that to the system, so it makes sense to build a system that closely matches and is slightly under your usage.  (However, we just learned that California is about to revamp the rules, and we may actually get paid real cash for any excess we send back to the grid.)

We've only paid for electricity in 3 of the last 8 years, maybe $500 in total.  (My wife took up fusing glass as a hobby, and the glass kiln is rated at 10Kw!  )

When we installed the system in 2001, I figured it would take 15 years to pay it back, but the rates have risen since then, and our payback time has shrunk almost down to 12 years.  The panels have a 25 year warranty (and really have a lifetime that is more like 50 years as they degrade slowly), so the rest is gravy.  

[azcycle]

Very cool, Darryl!

[darrylri]

If you live somewhere that has constant winds, you are far better off buying a windmill.  (We have gusty conditions alternating with still air, which doesn't work well.)  

Of course, the cheapest thing you can do is to cut back your usage, but what's the fun in that?  Actually, we went through and changed out as many bulbs for CFLs as we could, as well as getting a new fridge and HE washing machine -- we're on a well, so water = electricity.