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# How to estimate/calculate electric costs

#1
05-07-19, 08:10 AM
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Join Date: Oct 2009
Posts: 10
How to estimate/calculate electric costs

Not a technical electrical question, but I've always found very helpful info thru this forum.. just confirmed landlord has hallway lights and building attic fan tied or wired to my box/bill. Hall light is on 24/7, and attic fan with on/off tied to temperature gauge appears to lead to large spikes in my bill over warmer months (it has been on days and early evenings much of the last week, with wide range of temps, averaging about 63).

How can I get or best estimate the related electric costs (I would think for obvious reasons )? Thanks so much in advance --

05-07-19, 09:47 AM
CasualJoe
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Join Date: Jan 2010
Location: United States
Posts: 9,786
You need to know the wattage, convert wattage to kilowatt hours and multiply times the cost of electricity per KWH. For example consider a 100 watt light bulb. 100 watts X 10 hours equals 1000 watt hours. 1000 watt hours is 1 KWH.

100 watts X 24 hours per day X 30 days per month = 72,000 watt hours per month. 72,000 watt hours divided by 1000 = 72 KWHs per month for one 100 watt bulb burning 24/7.

72 KWHs X 14 cents per KWH would be a monthly cost to operate 24/7 of \$10.08.

14 cents per KWH is arbitrary, check your own electric bill to get your local cost of electricity, it's probably closer to 20 cents after all taxes are added in

#2
05-07-19, 09:47 AM
Member
Join Date: Jan 2010
Location: United States
Posts: 9,786
You need to know the wattage, convert wattage to kilowatt hours and multiply times the cost of electricity per KWH. For example consider a 100 watt light bulb. 100 watts X 10 hours equals 1000 watt hours. 1000 watt hours is 1 KWH.

100 watts X 24 hours per day X 30 days per month = 72,000 watt hours per month. 72,000 watt hours divided by 1000 = 72 KWHs per month for one 100 watt bulb burning 24/7.

72 KWHs X 14 cents per KWH would be a monthly cost to operate 24/7 of \$10.08.

14 cents per KWH is arbitrary, check your own electric bill to get your local cost of electricity, it's probably closer to 20 cents after all taxes are added in

#3
05-07-19, 10:09 AM
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Join Date: Oct 2012
Location: Jersey
Posts: 62,054
We can tell you how to figure the rate but finding out what the current consumption is a bit harder.
You can see the hall lights. Can you get to and see the attic fan ?

If you can't get to the attic fan you could use an average of 250 watts while running.
Then you have to estimate its running time.

debndulcy voted this post useful.
#4
05-07-19, 11:49 AM
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Join Date: Oct 2004
Location: WI/MN
Posts: 18,870
What are you hoping to accomplish - get money back from the landlord?

Personally, I would either live with this or move, as trying to get compensation back from a landlord would be likely enough to taint the relationship that I wouldn't want to live there anymore anyway.

debndulcy voted this post useful.
#5
05-07-19, 04:09 PM
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Join Date: Oct 2009
Posts: 10
Yes, I do intend on getting some reimbursement from the landlord, as I believe it would only be fair (and it follows a pattern I need to address before leaving here). He said the hall light is 'the same as having a night light on, 2-3 watts, a 20 year bulb". There is a rather large spike in my elec bill from this time of year thru summer and into early/mid Fall -- and I have purposely not used AC, just a large box window fan and as needed, an additional floor-standing rotating fan, in one room where I spend the majority of time -- yes, all to save \$\$. (I'm in a third, the top, floor apartment.)

A representative of our power company is coming to review the situation in 3 days. I need to be able to understand whatever 'light' (hah!) he can shed on the matter. I can't get to the attic fan, but landlord, etc, can easily with a ladder.

I much appreciate the info on how the cost of electric/bill is calculated; Many Thanks for the replies. My inclination was to simply seek reimbursement based on the spike (using rate and cost as best indicated in monthly bills (with your info as a help), but it's altogether tedious as I've been here for four years. I have nothing to account for the hike In warmer weather/summer, especially as I cook and stay inside less.

#6
05-07-19, 05:19 PM
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I'm not sure why the power company is coming. They don't usually get involved in problems like this especially when you know what the issue is. You said you had confirmed that the landlord had connected the hall light and attic fan to your electric panel.

What is a "spike" in the electric bill ? \$25 a month to \$35 a month ?

#7
05-07-19, 05:57 PM
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Join Date: Oct 2009
Posts: 10
Agreed, re the power company; I was quite surprised. Landlord took that road after giving me some mumbo jumbo that didn't make any sense. It's more the underlying honesty issue, though over 4 years, \$10/mo increase (yes, as you suggested, though I was looking at the graphs showing 2/5 increase, more than monthly statements) X at least 5 months (the hottest) = about \$200. Not going to break me, but it kills me that I was trying to save \$\$ by not using AC, and yet have been paying for other building heat management. --- When I turn my box's breaker switch to off - both the hall light and attic fan go off.

#8
05-07-19, 06:37 PM
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Join Date: Oct 2008
Location: New England
Posts: 9,457
Since you have the electrical panel and breaker identified you could pick up a power monitor, something like a Kill-a-watt meter. It would clamp over the wire feeding out of that breaker and give you a total use over whatever time you have it connected. My only concern would be you opening up the landlords electrical panel. Others here will advise on that issue as well.

Bud

#9
05-07-19, 09:34 PM
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As long as you're not running AC and assuming you don't amass a lot of electricity use for heat, the difference in your bill month to month as the fan starts running would be a rough estimate of the cost of the fan.

#10
05-08-19, 10:37 AM
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Join Date: Sep 2005
Location: USA
Posts: 5,831
I've heard of the power company helping figure this out (sometimes it's the local building department). The landlord should be paying for all those common area items, and they'll help figure out what things might be cross-connected, get the landlord to fix them, and they might even fix the bills for you (refund you and charge the landlord).

I would try to be there when the power company shows up. That seems like an awfully high spike for just a fan and a light or two. How many other units are there in the building? Do any of the others have window or central AC?

Every once in a while you hear a story about one unit paying for the electricity of 10 or something crazy like that.

Hey, even if the landlord owes you \$10 for the last 4 years of electricity, he should pay you that \$10! (and I say that as a landlord myself)

debndulcy voted this post useful.
#11
05-09-19, 09:14 AM
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Join Date: Jan 2010
Location: United States
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When I turn my box's breaker switch to off - both the hall light and attic fan go off.
Since you have your own electric panel in your apartment and have confirmed the power comes from it you could also now identify the individual branch circuit breakers for the attic fan and hall lights, I doubt they are on the same breaker. Once they are identified you could just turn off the attic fan breaker . The landlord inevitably will figure this out so plan on a confrontation that might turn out to be an opportune time to ask for reimbursement of what he owes you.

Since the power company is coming out, ask the rep about the rates you are being charged; both winter rates and summer rates. The switch to summer rates probably also contributes to the spike in your bill.