How can I reduce my electric bill?
September 4, 2008 6:27 PM   Subscribe

First time living alone, and just got my first electric bill... what's using so much power? How much power does my computer really use?

This may seem like a stupid question, but any apparent stupidity is just lack of experience, as I've never lived in situations where I was completely and solely responsible for all bills before. I live in a 600 sq ft apartment with central air. Stove/oven and water heater are both gas, so the big draws on electricity are (presumably) the AC and my 24" iMac, which I use as both a music server when I'm around the apartment and connect to remotely from my laptop when I'm at school, so it's running 24/7. A large and bright display like that probably draws a fair bit of power, but when I'm not using it the display shuts off very quickly, so the display is usually off. (I have a TV as well, but it's also usually off.) I generally have the AC on at night, but off otherwise. I'm very good at shutting lights off when I'm not here, keeping the fridge door securely closed, etc. The computer is not doing processor-intensive activities when I'm not here... it has the standard set of OS X background processes going, an hourly Time Machine backup, and an IRC session in the terminal that I'll connect to remotely from my laptop or my phone when I'm out. That's it.

So, I didn't think I used a lot of power, but I received an $80 bill for less than a month's worth of power use (I moved in on 8/17). This was a good deal higher than I was expecting, because I thought I was fairly judicious about energy use and I'm not sure what I can target to reduce that bill. Is most of that bill going to be the AC, or could I put a significant dent in it by putting my computer to sleep when I'm not here? I can learn to live without the convenience of remote access or a streaming music library if it'll reduce my bill in any significant way, but my (potentially incorrect) understanding was that computers didn't use a ton of power these days and that displays were where most of the power use came from. Maybe I'm wrong?
posted by Kosh to Home & Garden (35 answers total) 3 users marked this as a favorite
One of the big users of electricity in your apartment is your refrigerator.

Some electric companies use extrapolation to figure out electrical usage, rather than reading the meter every single month. If the former tenant at that address was a profligate user of electricity, then that may be why your bill was high.

Also, your power use will peak in summer because of the AC.

Having said all that, you didn't say where you are located. There are a lot of places where $80/mo for an apartment dweller with air conditioning is quite normal.
posted by Class Goat at 6:34 PM on September 4, 2008

Shutting off my computer at night cut my power bill by about $15-$20 a month - I'm in a slightly smaller apartment, also gas stove and heat.

There are also devices you can use in individual plugs that gauge the draw - that might be interesting if you're looking for a culprit.
posted by restless_nomad at 6:36 PM on September 4, 2008

Often your power company will give you a meter for free. It shows you exactly how much power you are using. Then you can shut things off one by one and see what the big draw is.
posted by sanka at 6:43 PM on September 4, 2008

Sorry, should've mentioned location... I live in Columbus, Ohio.
posted by Kosh at 6:43 PM on September 4, 2008

There are tons of variables here that would help (mostly where are you?) but I would bet about 50% of that is the AC.

From what you've said I would suspect that the power consumption in your house is, in order:
- AC
- Mac
- Refrigerator
- Incandescent bulbs

Though that depends a lot on the age and suitability of your appliances, etc.

Sounds like a Kill A Watt might be a good investment.

It usually takes several months in a new place to find out what it really costs to live there. Does your electric bill (Or your account on their web site) show historical data? When I moved into my place I could see on the web site what the previous tenant paid last year.
posted by Ookseer at 6:44 PM on September 4, 2008

I personally don't think $80 a month sounds that bad. If your power supply was pulling peak usage every month while running for 31 days straight, you'd be using 208.32 kWh, which you can multiply times the rate on your electric bill to find out what your maximum cost for leaving it on all the time is. IAMAE, however.

I'm pretty sure there's an option to schedule startup and shutdown times. That would save some energy while having your network storage available when you need it.
posted by cellphone at 6:45 PM on September 4, 2008

You could buy a Kill-A-Watt for about $20 either new or used, audit your usage, and then sell it on eBay for about the same price.

When the air conditioning is on, you keep the place pretty well sealed, right? An open door/window will let in heat if you have the thermostat set for a lower temp than outside. Also, if your refrigerator is really old, that could be your problem. If it came with the apartment and/or you aren't planning on staying long, it may be cheaper to keep it, but it's definitely something to calculate out. I'm not sure about the specifics, but I've heard that older refrigerators can use something like 60% more energy. A small one probably would use less power, too, if you're living on a college diet (IE condiments and soda).

You could also set up your iMac to be woken on LAN, which you can do with this app. I haven't done it, but others say it works. I doubt your computer is causing the bill to go up so much, but every bit helps, and it's better for the environment.
posted by mccarty.tim at 6:49 PM on September 4, 2008

Yeah, it depends on where you are. My bills are a little less than that for a 800 sq ft place, but I barely run the AC, religiously turn off my computer and unplug chargers, etc.

That being said, it might be worth checking to see if your meter is hooked up/labeled properly. Are you in a new build? When I moved in to my place last Spring, I was shocked to find that my electricity bills were $150 a month. I talked to the power company and the builder to try and find the problem, and all I got out of it were pamphlets on how to cut down my electricity usage. Finally, I shut off ALL of the power in my place at the breakers and noted the meter reading (building management gave me access to the meter room). Four hours later, the meter had gone up by 4 kwh. That still wasn't enough to get the power company out -- I had to dig up the email address of a VP and it still took a couple of weeks for them to come out an investigate. They found that the label on my meter and my neighbors had been switched. I got a credit for about half of the money that I had shelled out for electric. All in all, it took 6 months to resolve.
posted by amarynth at 6:50 PM on September 4, 2008

The 24" Imac might use 100watts. Thats 100*24*30=72000 watt hours, or 72kwh. Look at your bill to see what you pay per watt-hour to figure out what its costing you to run. I pay 13c/kwh = $9.36/month to run your mac 24/7.

Buy a kill-a-watt for more around-the-home fun.
posted by SirStan at 6:50 PM on September 4, 2008

Googling implies that an iMac running is something like 110W, so let's say 100W with the display off (displays were the big power drain back in the days of CRTs, not so much anymore.)

So a quick bit of math gives you 72 KWh for you iMac. Or so. Your profile says you're in Ohio, let's assume that you're about average for Ohio, so going by this table, you're paying 9.25 cents / KWh. So we've got about $6.66 (spooky!)

Of course, these are very very rough numbers.
posted by Lemurrhea at 6:51 PM on September 4, 2008

Your computer isn't making that big a difference.

Does your bill show how many kWh you used last month? Can you compare bills with neighbors in your apartment building? That would probably give you a more meaningful basis of comparison.
posted by adamrice at 6:52 PM on September 4, 2008

Definitely the A/C and your computer. I am always amazed by how much energy a desktop computer can use. Also, because you're running it all the time, your A/C has to work harder to cool your place down. If you only really need the A/C at night, I would suggest getting a fan to move air around and putting the A/C on a lower-intensity setting. Having better ventilation can do wonders for feeling cool.

Also, poor insulation or leaky/drafty windows can significantly increase your energy demand. Make sure that you do all you can to cool your place off during the day (when the A/C is off) so the A/C doesn't have to run as hard during the night - e.g. lights off, low-energy setting on computer, shades/heavy curtains drawn. It takes less energy to cool a place off from 78 to 74 degrees than from 85 to 74 :)
posted by kookaburra at 6:56 PM on September 4, 2008

dude, its the AC. 80 per month actually isn't that bad for the summer in Ohio.

A bit of advice - keep the AC on all the time, especially if you're in the humid midwest. It takes a LOT of energy to cool an apartment down from midwestern summer humidity (since one of the AC functions is humidity removal and this will cause much more power drain in Ohio than say Colorado) and heat. if you're shutting off the AC every day, then you're giving the heat a chance to get back in and starting the whole cycle all over again. Keeping the AC on will ensure that all the AC has to do is keep things cool once their cool (about like the energy it takes to go from 0-60mph in your car compared to the energy it takes to keep it at 60). That might help.

I would normally say open windows and keep the AC off, but the humidity in Ohio will destroy your fancy computer components.
posted by mr_book at 6:59 PM on September 4, 2008

and then one more thing to check on is when the previous tenants moved out. If they lived in the apartment through 8/16 and left the windows open and the AC running it's possible the power company screwed up and carried their charges to your bill. Don't assume the they got it all worked out correctly.
posted by djpappas at 7:05 PM on September 4, 2008

If the fridge running constantly?

Check the grating/venting on the back (and underneath) your refrigerator - it may be extremely dusty. Vacuum off, then wipe down. I have to do this every 6 months or my fridge runs constantly (it shouldn't, the compressor should kick in for awhile, then off)

But - your main culprit is probably the AC. You should also save a bit by going to compact flourescents - but if you have a work/desk/reading area, keep a traditional bulb there - much nicer to work/read with.
posted by jkaczor at 7:08 PM on September 4, 2008

When I lived in an older apartment, I found that the AC tripled the electric bill. $80 isn't that bad. It should go down significantly this month.
posted by Ostara at 7:10 PM on September 4, 2008

I'm very good at shutting lights off when I'm not here, keeping the fridge door securely closed, etc.

Do you clean the refrigerator coils? It wouldn't account for a big chunk of your bill, but dust/fur encrusted coils can lower the efficiency of the refrigerator, thus causing it to work harder and use more juice.

See step 1 here, and this short video.
posted by CKmtl at 7:15 PM on September 4, 2008

Thanks so much for all the tips and input. I haven't cleaned the fridge, no, so I'll take a look at that. It doesn't sound like it's constantly running, but I'll keep an eye on it. I'll look into the Kill-a-Watt too. The 0-60 explanation was helpful for understanding how the AC works. Either way, I hope the autumn rushes in quickly because the evening humidity is what drives me to turn the AC on more than anything--I'm fine with a fan and open windows during the day. I haven't received my paper bill yet (I was checking online because I knew the meter reading was yesterday, and now I can't double-check what the webpage said because their server is now not working...), so I'll be sure to scrutinize that when it arrives and look for any discrepancies.
posted by Kosh at 7:25 PM on September 4, 2008

I work for an electric company in Connecticut (and if you look at Lemurrhea's table, you'll see why I envy your $80 bill), and from what I gather from listening to the reps maneuvering through high bill complaints (again see table), central air is a very very high user of electricity, especially if the system hasn't been updated recently or if the system just happens to be an energy hog. (Does the unit have a timer? A few minutes before I get into bed, I set my window air conditioner to go off in an hour. Luckily I also have a remote so if I wake up in the middle of the night hot, I can reset it for another hour.) However, the most relevant factor in terms of energy consumption is what temperature you're keeping your central air on. The cooler you set it, the more energy it's going to use and each degree lower makes a pretty substantial difference.

Also, In Connecticut, the rates are actually higher in the summer. I don't know if this is true in all states, but this might also be part of why your bill is high. The reason for the cost increase is simply one of demand; people tend to use more electricity in the summer. In summer, not only are people running air conditioners and fans and pool pumps, but everything that needs to stay cool is working harder- this includes your fridge and any electrical appliance with a fan in it. I really recommend waiting to see what your Fall bill looks like and if it's still very high, re-investigate. Maybe call your local electric company. If you're gone from the apartment all day, they may be able to put you on a "Time Of Use" rate (where you're charged more than the standard rate during on-peak hours, but less during off-peak, which is generally at night).

And seriously, don't compare your usage to other people in your building. Unless they have exactly the same appliances as you and use them at exactly the same time and in the same manner, it's not going to help you figure anything out.
posted by eunoia at 7:30 PM on September 4, 2008

Do you have an amplifier for your music? I tested currency usage on mine and found it interesting that it takes the same amount of electricity to amplify silence as it does to amplify music. So, if you have one of those subwoofer speaker setups, then that is sucking watts 24/7. Switch it off when you're not using it.

Also, your TV may not be on, but it is probably in standby mode. My TV and DVD player uses about 15-20 Watts in standby, which is a waste just so I can turn them on with a remote. I bought a $2 powerbar that has a switch and plugged all my standby devices into that. When I want to watch TV, I turn the powerbar on. Easy.

Also, as said, your AC is definitely the power suck here. How many BTUs? It's probably at least 1000 Watts. So that will dwarf other appliances.

Oh, and electrical companies have loads of extra BS charges. A flat "delivery charge", "debt-reduction" charge or whatever. Check to see what you'd pay even if you used 0 Watts.
posted by kamelhoecker at 7:49 PM on September 4, 2008

The 0-60 explanation was helpful for understanding how the AC works.

That really isn't how AC works. While very high humidity may make it less energy intensive to keep your AC on, it is far from a foregone conclusion. If you only have the AC on for a few hours in the evening, I strongly suspect you'll use less energy than running it all the time.
posted by ssg at 7:50 PM on September 4, 2008

if you're gone for most of the day, a programmable thermostat would be a big saver. You can set it to just turn on the AC an hour before you get home. The house will be cooled for your arrive, and it will turn back off shortly after you go to sleep.

I'm in south central PA, and your bill doesn't seem out of line to me.
posted by jrishel at 8:23 PM on September 4, 2008

AC is an electric bill killer. On the one hand, you mention central air, which suggests your building isn't terribly old, but if it was cheaply built, the insulation might not be great.

While living in Texas, my summer electric bill for a 750 square foot space was easily $150 a month thanks to poor insulation and crazy high ceilings (over 16 feet!). On the other hand, my winter electric bill was around 45 bucks.

You may be able to shave a dollar or two off your bill by changing your habits, but the real issue is mother nature.

Want your place to be cool in the summer? $$$
Want your place to be warm in the winter? $$$

By this time next year, you'll be used to the arc that your electric bill follows.
...Lower in fall
...higher in winter
...lower in spring
...higher in summer
posted by 2oh1 at 8:50 PM on September 4, 2008

It is not true that running your ac all the time will save you power. The car analogy is apt, if misapplied: do you think you would save gas if you somehow left your car going 60mph all night, instead of parking it and accelerating again in the morning when you left for work?

Heat always tries to equalize, just like pressure. The cooler it is in the house relative to outside, the faster it moves in from outside. If the AC is on, this pressure will remain high throughout the hottest part of the day, causing much more heat to move into the house. If the AC is off, the house will equalize at a temperature where heat is no longer moving in very quickly (or at all). The house will also start to cool on its own once the sun sets.
posted by Nothing at 9:04 PM on September 4, 2008

I work for a natural gas utility. We provide Energy Depot free for our customers. ;) They can use it to calculate both gas and electric usage for a variety of appliances, and even input energy costs over time to create an energy profile and receive tips for lowering energy bills.

You mentioned checking your online bill because you knew when your meter was read. Your electric utility may not read the meter every month, but you should be able to submit a reading yourself in the months when your bill would normally be estimated. Check your utility's web site to see if you can input a meter reading online. If not, you might be able to call in a reading or mail in a card. Then you won't ever be surprised by a larger-than-expected catch-up bill.
posted by Joleta at 9:15 PM on September 4, 2008

I live in Philadelphia in a pretty small (no idea on square footage... maybe 800?) 2 bedroom apartment. The meter gets read every month, and my latest bill (for 29 days ending 8/19) shows we used 344 kWh, and it cost $55.54. If you can see an electronic copy of your bill, see if it says when the next meter read date is. That might give you a hint as to if it's an estimate or an exact reading.

A friend of mine in lives on the 4th / top floor of a building (I'm on the 2nd) and her bill was over $100 for a much smaller apartment. Turns out she hadn't changed the filter on the central air unit in... well, probably a year. So take a look at that, maybe the previous tenants never changed it either.

I turn off my laptop during the day, which might make a difference, and most of the lights I can reach (and all lamps) are CFLs.

Oh, and lowest electric bill ever was mid-March to mid-April. We used 146 kWh & it only cost $26.49!

It's also very humid here in Philadelphia, I have a programmable thermostat but also make sure if I know I'm going to be gone extra long to just turn everything off until I get home. If your apartment's pretty small, it should cool down quickly in the evening once you turn the AC on. Just don't leave all the windows wide open during the day so you can avoid too much humid air coming in.

My guess is that it doesn't make a huge difference, but I also keep several large bottles & jugs of water in the fridge. In addition to providing drinking water in the event of the apocalypse, it helps keep the fridge temperature a little more stable after I open it just to see what I have in there. I do that more often than I need to. When you open the fridge lots of the cold air flows out, so anything that displaces cold air can kinda help. Especially for fridge-starers like me.

Is it possible to be a utilities geek?

posted by polexa at 10:23 PM on September 4, 2008

Kosh - here's the guy that will help you figure this out - michael bluejay. Honestly, I spend 40 hours each week handling calls just like yours. I've looked at countless utility sites and he has the most concise guide to figuring out your bill. Anyone who is reading this - go to this site before you call your utility.
Do you know if your opening read was an actual or an estimated read? If the opening read was estimated incorrectly your bill might be incorrect.
As for a/c - if it's not on, it's not using electricity. Your place is small enough that it probably doesn't take too long for the a/c to cool it down. The question arises: will I spend more to run my a/c while I am not there or for it to cool my apartment while leaving it off or at a high temperature? You can run some experiments, but chances are leaving it on will cost more than turning if off when gone for extended periods. You might be uncomfortable for a bit but think of the money you are saving...
Also you have to think about how usage/cost of an item is calculated: watts/1000 X hours per day X days in read period X kwh charge = total cost to run an item all month. I spend a good part of my day convincing people that it would take 500 12 watt CFCs to equal the same wattage as their 6000 watts of central a/c.
Keep in mind - every line item on your bill has to be approved by the utility or public service commission.
Definitely agree on the kill-a-watt - newegg had them for $13 recently.
Finally, learn how to read your meter. You can always email and I can tell you how to figure out your kw draw from either a digital or 5 dial meter. So you can spend some time figuring out how much your water heater is using, or your fridge, or your beer cooler ...
posted by TomSophieIvy at 10:34 PM on September 4, 2008 [1 favorite]

Just a thought — was your first bill high because it included the deposit?
posted by Brittanie at 11:09 PM on September 4, 2008

Just as another data point, my apartment in Memphis was empty all summer, all I left plugged in was the electric range and the fridge (set on the lowest setting). No A/C, no lights, surge protectors turned off, etc. My bills were about $15/month for that level of usage for the time period. I've been back less than a month and the bill I just got was twice that, mostly due to A/C.
posted by DiscourseMarker at 11:54 PM on September 4, 2008

First time living alone, and just got my first electric bill

The first time I got my first electricity bill it was substantially higher than I expected. As in, $800 higher than I expected.

It turned out that one of my housemates misread the meter(can you guess why?), and used that number as our opening meter reading. So the electricity company over-estimated our usage by 1,000kWh and used that to work out estimated bills.

So that's my suggestion to you: Check that the meter readings on the bill match the values shown on the meters.

Nowadays every time a bill comes I photograph my electricity and gas meters and telephone those readings through to the power companies - no careless readings or estimated bills for me!
posted by Mike1024 at 3:10 AM on September 5, 2008

That zero-to-sixty analogy you found useful is awful.

If you were unnecessarily letting in heat, then that's bad. If you're cooling when you don't need to, that's also bad. At some point you break even for starting from off.

To add to the bad analogy, if you only drive for 10 minutes in the morning and 10 minutes at night, then keeping your car running at 60 miles per hour for the 12 hours you're not in it is stupid, and starting from zero each time is way, way less fuel consumption.
posted by cmiller at 4:26 AM on September 5, 2008

I'm currently working with my local electric company on the question: if the temperatures in the area were, on average, 2 degrees higher in the July bill range than the August bill range, why was it another $40 on the July bill than the August bill? It doesn't make a lot of sense.

And they agree with me: it doesn't make sense.

The current working theory with them - which they're looking into - is that the three blackouts we had in the area ended up screwing my electric bill by making the refrigerator kick in hard when the power came on again. (Interestingly, the three blackouts were not, in fact, direct power company issues; a blown transformer can happen anytime, and the Fourth-of-July-weekend drunk driver meets utility pole incidents are not their problem.)

I recommend doing some research on the appliance power draw (I moved into my apartment last year in June; they replaced the fridge, stove, and dishwasher between the last tenant leaving and me moving in), doing the recommended cleaning, and once that happens, calling the power company and asking - politely! - if they could explain the power bill to you. Explain you're a first-time renter and not quite sure how to read it. I did that with my weird power bill surge - that it was a sudden and very strange jump that didn't quite seem to make sense and that it might just be me not understanding - and the operator was more than happy to help educate me.
posted by mephron at 6:42 AM on September 5, 2008

Take every appliance in your house, big or small, that you don't have on all the time, and put a power strip with a switch on it (like a surge protector) between it and the power socket. Leave these power strips off all the time, and only switch them to "on" when you want to use the appliance.

Machines with power supply converters (which means almost everything) will draw power even when they're not turned on and operating. Power company workers refer to them as "vampires", because they slowly drain power constantly. If you open the circuit that these things are on, they won't use any juice.

Examples of things that you really ought to have on "open circuits" like this:
* cell phone chargers
* other battery chargers (dustbuster, portable power tools, cameras, shaver, electric toothbrush, etc.)
* power supply adapter (that you keep plugged in for convenience, even if nothing is plugged into it)
* microwave
* toaster oven
* blender
* stand mixer
* stereo
* TV
* DVD player
* hair dryer

Examples of things that should NOT be on an open circuit (this stuff should be obvious):
* smoke detector (or any safety warning device)
* refrigerator
* DVR box

In general, A/C units and lights are actually turned off by opening the circuit, so you probably don't have to worry about them. Hooking them up the same way probably couldn't hurt, though.
posted by Citrus at 7:53 AM on September 5, 2008 [2 favorites]

We live near you and our split level 3-br house electric bill was $105 last month. To me, an 1-person apartment's AEP bill should not come that close to one for a house of 2 adults and 3 kids!
posted by I_Love_Bananas at 9:31 AM on September 5, 2008

Uh, this is a really stupid question, but is the $80 only for the electricity, taxes, and other fixed costs? Or does it include things like a deposit or a connection fee? The reason why I ask is that I notice you said it's the first time you've lived alone and also your first bill. There may be some charges associated with you beginning service.

$80 seems to me like an awful lot for just a couple weeks' worth of electric service for such a small place. Check the line items on your bill.

On preview, what Brittanie said.
posted by Robert Angelo at 2:13 PM on September 5, 2008

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