Large electric bill spike due to A/C

[jimbobber10]

Nice site guys/gals!
My electric bill tripled this past month, here in Clev., OH. Tripled compared to last month and 13mo's ago (2,000 kilowat hrs used this yr in June, compared to 800 in both previous Junes' usage).
I look at the disk in the meter and noticed it starts spinning like it's going to take off as soon as the AC is turned on.
I tuned off the 220 breaker in my main panel and turned the unit on to find the same meter results.
It is a 23 yr old unit, but is clean and well maintained.
The big is cold and wet- the little is warm (seems to be the recurring theme on this site).
Please advise, I am calling the electrician that did my panel to see what he says.
Thank you

[danski0224]

Last June was cooler, at least where I am.

Check the average daily temp for both years.

That 23 year old unit is sucking up the juice anyway. It will only cost you more next year.

[jimbobber10]

7 degrees difference in avg temp. Is that enough to warrant tripling the kwh used? Here's the usage readings. . .
June 04 June05 July 05
842 765 2068

Looking at the bar graph makes me want to puke.

HELP

[danski0224]

Could be enough of a difference. Probably wouldn't hurt to have the utility come out and make sure everything is ok.

Ever check the amp draw on that old unit?

What is the average daily temp difference between June and July 05?

[mattison]

Like said by Danski, check the amp draw against rated. Also can you tell if the cycles are longer than before?

[jimbobber10]

OK, thanks for the reply.
I don't really know how to check the amp draw, but I guess I can figure it can't be more than 15 amps- as the breaker is 15amp.
Once again, I turn off the 220 breaker for the coils and all that, turn the AC on, the fan blowns warm air and spins the meter disk like it's going to fly away- so I think I've isolated the circuit that's drawing the amps. Could it be the fan shorting or something?
The avg daily temp is 14 degrees more than last month's and the circuit pulled triple the amount of kwh (765 compared to 2068).
The last largest usage was in Aug of 04 (1200 kwh) and the avg temp was 71 degrees (only 3 degrees less than my huge spike of 2068 this past month). I'm not a big fan of AC and haven't set the thermostat any lower than at any other time (approx 78 degrees).
To understand my complaint further, I've never seen a bill totaling more than $120, this month is $241 and it looks like I'm headed for another huge bill- as now, everyday, I'm using about 75-100 kwh's.
I look forward to your responses and will post the results of what I figure out today.
Thanks, like I said, this is the best (and really only site) that help out like you all have.

[mattison]

I can figure it can't be more than 15 amps- as the breaker is 15amp.

The breaker for the outdoor unit is going to be a 30 - 40 amp double breaker.


Once again, I turn off the 220 breaker for the coils and all that, turn the AC on, the fan blowns warm air and spins the meter disk like it's going to fly away- so I think I've isolated the circuit that's drawing the amps. Could it be the fan shorting or something?

How is your home heated? Is it electric heat strips in the furnace or gas? It's starting to sound like you may have electric heat stuck on.

[danski0224]

In the battle between A/C and resistance heat, who wins? :D

[jimbobber10]

I have a gas furnace.
I started by counting how long it takes the disk to make one revolution while everything was on. It took 5 seconds (wow).
Going thru the breaker panel, I fould that when I turn off the AC breaker (2 - 30amps), it takes 10 seconds for one rev. I would guess this is normal.
Then I turned that breaker back on and turned off the Furnace breaker (20amp) and the meter disk slowed down to 22 sec for one rev!!!!!.
So I believe I have isolated what is drawing so much power. I also have a blower switch on the side of the furnace that, when I turn it off, causes the same result.
Can anyone give ideas on what might be wrong that would cause the blower on the furnace to draw so much power???
:wall:

[danski0224]

Blower motor could be going bad. Did you check the amp draw? I looked at one yesterday that was drawing 22 amps and never got up to speed (capacitor was good). Supposed to be around 10 amp draw...

[jimbobber10]

Welp, the blower is drawin a normal 6 amps. I went ahead and cleaned it. I notice on the outside unit, that the contacts in the box inside the outdoor unit are toast. Could this cause this large of a usage spike? I'm going to replace it today.

[KField]

The contactor would not be responsibel for the high usage unless it was welded and caused the outdoor unit to run 24/7. If that happened, you would notice other problems. It does sound like the problem is with the furnace circuit but since the 24 volt control power to the outdoor comes off of the furnace, you may be fooled into thinking all the draw is from the furnace. When you turn off the furnace circuit, the outdoor unit will stop also. Your usage does sound high and if you keep checking, I'm sure you will find the problem. Amp readings are the most helpful in the search.

Ken