Our summer hydro bill for an empty home with a humidity control is around $35/$40 per month.
We leave our fridge on because that is what the tech recommended.

Why don't you call the electric company.

We had something similar from the time the house was ours before we moved in. The electric company (SECO) checked the meter and realized that they had read it wrong. The bill; was corrected to a lower, correct price.

Cost of electricity
 

We had a dehumiditat and that worked fine but we recently installed a Nest Thermostat and it can be controlled remotely via wifi. The first bill was higher then using the dehumiditat but this month it looks like we save a few dollars and expect our bill to be in the 40.00 range for a smaller designer. The nest needed to be set at 81/82 degrees and the humidity has been around 53/55%. With the dehumiditat you never knew the humidity in the home, we set it at 60%. Tom at TheVillagesAV supplied and installed the nest thermostat. He also installed a smoke detector that can be monitored via wifi also. I love gadgets and technology. There have been days in September when the ac did not run at all, these charts are on your account and you can at it for everyday.

just got my first ele.bill..........$40 for turn on..........$5 something..........$25 for ele, empty designer, ac set at 80.

We have bills around $50 for our designer when we're not there in the summer. Your's is much too high. Do not empty and unplug your refrigerator as someone suggested. It may stink and be ruined. Always leave the door open if you unplug it. Anyway, new refrigerators use very little electricity...about $5 per month is typical. If you have a DVR that's plugged in, it will use at least as much.

Electricity Usage
 

Same situation and same amount.

For those who aren't familiar with SEER (a measure of AC efficiency), that's a typo - he means 15, not 1500.

One other thing be sure to check your air filter on a new home. It may have been installed long before you moved in. Ours was pretty dirty even though no one was living in the home. A dirty filter will increase your AC cost. You can get replacements from your AC company or at Ace Hardware.

Check with your builder or home warrenty dept. If I am not mistaken,all the new homes south of 466a have a humidistat built into the new ac units, When you buy a new home your ac company will come to your home and give you a briefing on how your system works. When replacing your ac filter, make sure it's an EXACT SIZE as the one that is in your unit now. HD has these in stock, made by Flanders Filters ,an American company. If the filter is slightly smaller than the original it will not filter the air properly.

We keep our designer between 72 and 75. 72 at night. Our bill was around 150.

Brrrrrrr - thats cold.

Thanks for all the advice. My house is somewhere around 2000 sq. ft. It was built in 2013. I live in Africa at the moment, so I can't check on anything right now, including past bills/usage, which I have never had because I had tenants for the past 9 months. I have my management company going over to the house today to check what they can. If they don't find anything, I'll be there in January to check for myself. I just hate to pay 3 times the monthly cost for the next 3 months. Which is why I asked for confirmation that it was high. I emailed SECO and they just gave me some crap excuse:
(After reviewing your account, I’m showing that on this billing cycle you were billed for 36 days of service. Normally you are billed for about 30 days. So this is one reason why your bill would be higher. Also even if no one is home and you leave your AC set to 80 degrees with the temperatures we have been having the AC will run very often.) I don't think this explains a $158 bill, but not much I can do until I get there in January. thanks everyone, I'll let you know if they find a reason for it.

If you leave for any extended time, don't forget to shut off your water heater. They also use a lot of electricity. Our bill runs about $150 in the summer months for a 1,900 sq ft home and us at home.

You have relatively new home. If it is like mine, it probably comes with a 10 years parts/5 year labor warranty on the AC system but you need to have an annual service on the system to maintain the warranty. I think there is a good probability that you have an AC issue plus you probably need to have an annual service anyway. I would instruct the management company to call the original AC contractor and have an annual service done. Assuming you have the same warranty as me, if there is an issue it wont cost you anything (except for the annual service - probably less than $100??). Eliminate the most likely causes first. Good luck as let us know how it all works out.