There isn’t one answer for how much it costs to run AC in California. However, once you understand some key factors related to your AC system, you can start to calculate an estimate for hourly usage.
Factors that will affect your AC costs include:
Price of electricity in your area
SEER rating (energy efficiency)
Hours of usage
Conditions of your home
Below we’ll take a look at each factor to help you gauge how much AC will run you.
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Cost Factor #1: Unit capacity
All air conditioners are rated by BTU’s (British Thermal Units). In simple terms, this refers to the capacity of the AC unit to cool your air.
In general, the higher the BTU, the more money it will cost you to run. This is because it uses more power, which costs more money in electricity per hour.
For example, if you have a 50,000 BTU central AC system, you’re going to see higher utility bills than if you were using an 8,000 BTU portable window unit; There’s a significant difference in capacity and power consumption.
That being said, BTU output doesn’t always determine your AC costs because it also comes down to your specific set up — which we’ll go into further below.
Cost Factor #2: Price of electricity in your area
The cost to run your AC will greatly depend on how much your city charges for electricity.
The price is billed in a measurement called kilowatt hours (kWh).
Here in Irvine, the rates are pretty high — ranging from $0.23 per kWh, up to $0.54 per kWh. (For comparison, in Utah it’s only about 10 cents per kWh).
To calculate how much you may be charged for your usage, use the following steps:
Step 1: Determine your AC’s kilowattage.
The equation is: Amps x volts divided by 1,000
For example, a central air conditioner with 54,000 BTU of cooling output has 50 amps and 208 volts.
So, 50 amps x 208 volts = 10,400 watts. Divided by 1,000 = 10.4 kilowatts.
Since electricity is charged in kilowatts, it’s important to know this number.
Note: Amp and voltage numbers can easily be found on the “specs” portion of an AC product website listing, or even on the unit itself.
Step 2: Multiply your kilowattage by how much your city charges per kilowatt hour (kWh).
Using Irvine’s base tier price of 23 cents per hour, we’ll multiply that by our 10.4 kilowatt usage:
10.4 kilowatts x $0.23 per kWh = $2.39/hour
That $2.39 is how much you’d be charged to run your AC per hour. So if you wanted to determine your monthly cost, simply times that by hours of use per month.
For example: $2.39/hour x 40 hours of use = $95.60/month
Keep in mind that these numbers are based off of the lowest tiered electricity rate. In California, most cities have adopted what’s called “Time of Use” rates that will change throughout the day. Make sure you’re aware of what your rates are.
Note: This example is based upon the AC needs of a 2,500 square foot home. If your home is smaller, your power consumption and energy costs will be less.
Cost Factor #3: SEER rating
The efficiency of your air conditioner is rated by a system called SEER (Seasonal Energy Efficiency Ratio). Similar to a car’s gas mileage, the rating essentially tells you how well your AC can perform in a typical range of temperatures.
The higher the SEER rating, the less expensive your AC will be to run. This is because the unit is more energy efficient and you’ll get more bang for your buck.
During a heat wave for example, if two AC units have the same BTU output, but one of them has a higher SEER rating, the latter won’t have to work as hard to cool the same amount of space.
SEER ratings range from 10-25, but to be certified by Energy Star it has to be at least 15.
Depending on where you live, investing in AC with a higher SEER rating could save you a substantial amount of money on your monthly utility bills.
Cost Factor #4: Hours of usage
The longer you run your AC, the more you will pay. However, in California your costs also depend on when you run the AC. If you’re using it during “peak hours,” expect to pay to pay more.
For many California counties, utility rates are highest on weekdays from 4-9 pm.
During the summer months especially, or when there happens to be a fire, residents are encouraged to cool homes at the start of the day, and then limit their AC during “peak hours” of the day when most people are home from work and using electricity.
To encourage this, many areas set “Time of Use” (TOU) rates that will charge different amounts depending on when you’re using power. In Orange County, peak rates can go up to as high as $0.54 per kWh.
Taking the example above, with the AC bill of $95.60/month, an increase of rate to $0.54 per kWh could cause your AC bill to go up to $224.64. That’s a huge cost difference, so definitely make sure you understand your TOU rates, and plan accordingly.
Cost Factor #5: Conditions of your home
Other factors that may increase your AC bill include:
1. Home size
The larger your home, the more expensive it will be to run your AC.
After setting the thermostat, your AC won’t shut off until the entire home has reached your desired temperature. For larger homes with more square footage to cover (including ceiling height) this means your AC will be running longer, incurring more electricity charges.
If your home is poorly insulated, expect to pay more for AC. This is because your home isn’t set up to limit the amount of hot air coming in, so your AC will have to run more often. Additionally, if your AC is constantly going on and off, the start up times will incur more power usage.
This only applies to central AC, but if your ducts need repair, your AC won’t be as efficient, and will increase your energy costs. Although it might cost you money to fix, the long-term savings are worth it.
Outdated air conditioners aren’t very energy efficient, and if it hasn’t been well maintained either, expect to pay higher electricity bills. In this case, it might be cost effective to replace it.
Want transparent prices from an air conditioning expert? Contact True Home Heating and Air Conditioning.
Our team of licensed technicians is here to listen to your specific AC needs and budget. With no obligation quotes and zero up-selling, you can trust you’ll get only the best advice for what’s true to your home.