Is it possible to use 30 KWs in a day?

[erikiksaz]

Our last bill amounted to 900 KWs, with that being 30KWs a day. There are four people living in this apartment. For the most part, computers are only left on when we're home, so that might be 10 hours a day. In addition, we don't use ac/heater, and we only watch tv for about an hour a day. Anyways, we also have an electric stove which gets used for about an hour. Besides for that, i don't see much else, besides for using the washer/drier four times a week.

Now, in a normal day with normal comp and stove usage, would there be ANY way to hit 30KWs? I'm thinking that's quite a bit!

But here's the kicker, both our stove and fridge are from the 80s. Our microwave (attached to the stove), has dials and an analog display!


I just asked my friend who lives with one other person. One has their comp on the whole day, whereas the other only uses it for 10 hours. They use their electric stove for about 30 mins a day (like us). They came out to 327 KW a month, which sets them at a little over 10KW a day. They only have 2 people, but the person's comp that is on all day would account for our third person. Anyways, our bill should not be tripling theirs! Could the old appliances be using that much more electricity?

 

[Heisenberg]

I assume you mean kilowatt hour's. My last bill was seven-hundred something kWH's, so yeah, I'd say it's possible.

Edit: Oops, the most recent bill was 500 kWH. The one before that was the 700, when the A/C was still being used off and on.

 

[Sluggo]

An old refrigerator will suck down electricity like its free.

Also a refrigerator isnt very efficient unless it is packed full of food (or beer )

 

[0roo0roo]

eh and if the cooling coils in the back are caked with dust thats no good

 

[scorp00]

I've used 1100 KWh's in a month before. I live in an efficiency too. So it's one small room, kitchen, and bathroom. I do have 2 computers on 24/7 and one of them is overclocked hard.

 

[minendo]

Gas or electric hot water heater?

 

[arcas]

Let's see:

You didn't give the specs of the computers but let's assume: each computer draws 200W when on. Each monitor draws 150W when on. They're on 10 hours/day. So this gives us 4 * 350W * 10 = 14KWh/day just for your computers and assuming that they're only powered-on 10 hours/day. That gives you 420KWh over 30 days.

Your clothes dryer probably draws between 5000W and 6000W assuming it's electric. We'll go with 5000W. You say you use it 4 times a week. I'll assume this means your household dries a total of 4 loads of clothes per week. Let's assume each load takes an hour to dry. That's 4 * 5000W = 20KWh/week = 80KWh/month. You're up to 500 KWh now.

I have no idea how much current a washer draws so I won't consider it.

Your stove. You say about 1hour/day. But you didn't say how many burners. Let's assume you only use 2 burners and no oven. IIRC, the small burners on my stove are 800W while the large burners are 1400W. Let's assume you use one of each for an hour a day. That gives you 30 days * 2200W = 66KWh/month. You're up to 566KWh total.

Your refrigerator, if that old, is inefficient. It's hard to say how much power it's drawing. Argonne National Laboratory estimates that the typical old refigerator draws around 1000KWh/year but there are a lot of variables. If yours frequently defrosts or runs constantly, it's going to draw far more than that. Let's assume your fridge is average and draws 1000KWh/12 = 83KWh/month. You're up to 649KWh total.

You didn't mention if your water heater was electric, how old it is, etc. I'm going to assume it is and that it's a typical 40gallon heater. Electric water heater heating elements typically draw 5000W. There are 2 in each water heater but usually only the bottom one is used (the middle one is kind of a backup/emergency reserve). Electric water heaters typically have a lower 'recovery rate' than gas heaters. Let's say 30 gallons/hour. If your heater is old, it'll be lower than that. You say 4 people are in your house. Let's assume 4 showers/day and assume that this is enough to remove all the hot water from the tank. So it's on 1.5 hours/day just to recover from showers. Let's assume it's on intermittently through the day otherwise and that this adds another 0.5 hours total (I really have no idea here...might be more, might be less). That gives 2 hours/day at 5000W * 30 days = 300KWh/month. You're up to 949 KWh for the month.

 

[bleeb]

I find these kinds of threads fascinating... =)

 

[eelw]

Buy a Kill A Watt meter to measure power consumption to find the power hungrey appliances.

 

[erikiksaz]

Originally posted by: arcas
Let's see:

You didn't give the specs of the computers but let's assume: each computer draws 200W when on. Each monitor draws 150W when on. They're on 10 hours/day. So this gives us 4 * 350W * 10 = 14KWh/day just for your computers and assuming that they're only powered-on 10 hours/day. That gives you 420KWh over 30 days.

Your clothes dryer probably draws between 5000W and 6000W assuming it's electric. We'll go with 5000W. You say you use it 4 times a week. I'll assume this means your household dries a total of 4 loads of clothes per week. Let's assume each load takes an hour to dry. That's 4 * 5000W = 20KWh/week = 80KWh/month. You're up to 500 KWh now.

I have no idea how much current a washer draws so I won't consider it.

Your stove. You say about 1hour/day. But you didn't say how many burners. Let's assume you only use 2 burners and no oven. IIRC, the small burners on my stove are 800W while the large burners are 1400W. Let's assume you use one of each for an hour a day. That gives you 30 days * 2200W = 66KWh/month. You're up to 566KWh total.

Your refrigerator, if that old, is inefficient. It's hard to say how much power it's drawing. Argonne National Laboratory estimates that the typical old refigerator draws around 1000KWh/year but there are a lot of variables. If yours frequently defrosts or runs constantly, it's going to draw far more than that. Let's assume your fridge is average and draws 1000KWh/12 = 83KWh/month. You're up to 649KWh total.

You didn't mention if your water heater was electric, how old it is, etc. I'm going to assume it is and that it's a typical 40gallon heater. Electric water heater heating elements typically draw 5000W. There are 2 in each water heater but usually only the bottom one is used (the middle one is kind of a backup/emergency reserve). Electric water heaters typically have a lower 'recovery rate' than gas heaters. Let's say 30 gallons/hour. If your heater is old, it'll be lower than that. You say 4 people are in your house. Let's assume 4 showers/day and assume that this is enough to remove all the hot water from the tank. So it's on 1.5 hours/day just to recover from showers. Let's assume it's on intermittently through the day otherwise and that this adds another 0.5 hours total (I really have no idea here...might be more, might be less). That gives 2 hours/day at 5000W * 30 days = 300KWh/month. You're up to 949 KWh for the month.

4 computers - using 350 watts per computer = 420KW - 50 dollars a month.
Washer - 1200 watts, 4 hours a week, 4 times a month = 19.2KW - 3 dollars a month
Drier - 5000 w, 4 hours a week, 4 times a month = 80KW - 10 dollars a month

As for the fridge, i have no clue, it doesn't show any markings on the front side, and i'm actually a bit scared to see what's on the back. Same for our electric stove. And our water heater, i don't even know where it is, last time the repair man headed outside to look for it.

Anyways, so far it's only 63 dollars a month not counting the fridge and stove. There's still an extra 70 dollars floating about, would it even be plausible to assume that the fridge and stove would use 30 each, and an additional 10 dollars worth of electricity allocated to other things (stereos, tvs, alarms)?

 

[arcas]

But as for the computers, i thought most considered them to only use up 50 watts or so once they're up and running? Or maybe that quoted figure was from older processors. We are all running at least Athlon 2000+.

I just checked my SmartUPS's firmware (it lets you query stuff like line voltage and load percentage). I'm running an old 1.4ghz tbird and a 22" monitor. Combined they're drawing 392VA which I -think- is somewhere around 275-300W. Probably half of that is the monitor. So my estimate of 350W combined might have been a little too high but it should still be in the same ballpark.

Okay. If your water heater is gas, then you need to come up with about 8KWh/day elsewhere. Over a period of a week, pay attention to the high wattage appliances you use and for how long. Things like hair dryers, vacuum cleaners, toasters, coffee pots...things that draw a lot of power and might run for a while. Ovens too. They'll draw roughly comparable to a clothes dryer. Unless you burn lots of lighbulbs, I wouldn't bother counting them. IMO, lights don't significantly contribute to a household's power usage, I don't care what people say. Unless you're burning 300W halogen lights or something.

(I went through this exercise about a year ago. My estimates were about 5KWh/day below what the power company said I was using so I wanted to make sure I didn't have a slow short in the wiring somewhere. Spent the better part of the afternoon turning circuits off at the breaker box and checking the electric meter. Then figuring out which appliances were drawing what. Got things down to about 10W that I couldn't account for. I eventually wrote it off as powering the AC-powered smoke detectors.)

 

[Toastedlightly]

Well... doesn't a power supply draw ~300 watts? and a moniter (19" CRT) draws someting like 200-250 (I wanted to put an inverter in my car...)

 

[Kibbo]

For your info, I have a small apt-style washing machine, it uses 350W.

 

[0roo0roo]

Originally posted by: Toastedlightly
Well... doesn't a power supply draw ~300 watts? and a moniter (19" CRT) draws someting like 200-250 (I wanted to put an inverter in my car...)

they might demand much more when starting up though.. esp the monitor.

 

[erikiksaz]

So, we do have about 10 KW left over every day...

I guess tomorrow i'll find out where the meter is, and have my friend turn off everything but the kitchen. That should allow us to see how much the two larger kitchen appliances are using.

Thanks for all the help guys!

 

[DrPizza]

Originally posted by: erikiksaz
So, we do have about 10 KW left over every day...

I guess tomorrow i'll find out where the meter is, and have my friend turn off everything but the kitchen. That should allow us to see how much the two larger kitchen appliances are using.

Thanks for all the help guys!

try making sure that absolutely everything in your apartment is off.... the meter shouldn't be moving at all if that's the case. If it's moving, then it's possible that you're powering an outlet or two in the neighbors apartment.

 

[aplefka]

Turning everything off and checking the meter is a smart idea. Every once in a while I do it just because it's cool to watch how slow the thing moves then how quick it moves when everything's back on.

 

[erikiksaz]

Okay, I FOUND THE WATTAGE RATINGS FOR THE FRIDGE!!

Hah, my fridge is about 20-24 years old, depending on which year it was manufactured. Anyways, it uses 1500 watts without the condensation eliminator, and 1700 watts with. Using a mean figure, 1600:

1600W x 24 hours a day x 30 days in a month = 1152 KW

@ 0.08 per KW - $92
@ 0.12 per KW - $138


These values are incorrect, as our bill is only 130 or so. Now i know that fridges don't constantly run at that wattage, as they will idle for a bit then start up again. I guess i'll have to sit and watch the damn thing for about 30 mins to find out how often it cycles on and off. But, without doing that, i guess i could assume that it is on for half an hour, and idles for half an hour. So that should be 800KW in an hour for the fridge:

800W x 24 hours a day x 30 days in a month = 576 KW

@ 0.08 per KW - $46
@ 0.12 per KW - $70

That must be it.

4 computers - 420KW
Washer - 20KW
Drier - 80KW
Fridge - 576 KW

This is pretty close to 900ish, so i guess the fridge is the culprit!

 

[arcas]

That's a pretty hefty current draw for a fridge. The sticker on mine says max current draw of 7.5A so that puts it at 900W max (which presumably means with the defroster on). Didn't see any numbers for normal operation but the sticker estimated overall usage of 515KWh/year. On the downside, it's only 22 cubic feet. So, you might save a fair chunk of money simply by replacing your fridge.