Factors That Impact Your Electric Bill

In our desert climate, weather is the single biggest driver of household electric usage. When temperatures climb, air conditioning runs longer and harder, which increases energy use even if you never change your thermostat setting. TEP bills are typically highest in the summer for this reason.

Your bill also reflects how efficiently your home keeps cool. Factors like insulation, window quality, and how much direct sunlight your home receives can affect how hard your air conditioner has to work.

Your bill includes average high and low temperatures for your ZIP code, which can help explain why your usage changed from one month—or one year—to the next.

Not all bills cover the same number of days. TEP billing cycles typically range from 25 to 35 days, depending on meter‑reading schedules. A bill that covers more days will usually be higher, even if your daily usage stays the same.

Your bill shows:

• The billing dates
• The number of billing days
• Your average daily energy use and average daily cost

If your bill seems high, comparing your average daily usage, rather than your overall usage, to the same month last year can give you a clearer picture.

Electricity use is measured in kilowatt‑hours (kWh)—the amount of electricity used by running one kilowatt of power for one hour. More time running high‑energy appliances like air conditioners, pool pumps, or electric vehicle chargers means higher kWh usage and a higher bill.

The best way to avoid being surprised by a high bill is to keep tabs on how much energy you’re using.

Energy is the only product most people buy without knowing how much they’re getting or what they’re paying. It can be very hard to tell, since the same thermostat setting results in variable energy use based on the outside temperature.

Your bill includes up to 24 months of usage history, allowing you to see trends and seasonal patterns. But if you want to make more proactive adjustments, you should make regular visits to our online energy tracker. My Energy Usage shows your daily and hourly consumption compared to your historic usage.

Phantom or “standby” power is energy drawn from appliances and devices that are not being used but are still plugged in. The average customer spends up to $100 each year on phantom energy loss, according to the U.S. Department of Energy.  Reduce phantom power with these tips.

Your bill may be higher if you have an outstanding balance from the previous bill. Double check your bill for an outstanding balance.

Changes at home often show up on your bill, including:

• More people living in the home
• Guests visiting for extended periods
• Working from home
• New electronics or appliances
• Home renovations or additions

More people and more time at home generally mean more lighting, cooling, cooking, and electronics use.

Adding electric equipment can increase your electric bill, including:

• Central or portable air conditioning
• Pool or spa equipment
• Electric vehicle chargers
• Heat pumps
• Additional refrigerators or freezers

While some technologies—like heat pumps or EVs—may raise your electric use, they can lower costs elsewhere, such as fuel or maintenance, and may offer long‑term value.

Solar customers may also see seasonal changes. Shorter winter days and cloud cover can reduce solar production, even though cooler temperatures do not harm solar panels.

TEP’s Budget Billing program spreads your expected annual electric costs into 12 more predictable monthly payments. Once a year, your account is reviewed to see whether you used more or less electricity than estimated. If usage was higher, your payment may be adjusted, reflecting an increase. Conversely, if you've used less energy than you've paid for, we'll owe you the difference.

Your total energy use is multiplied by the rate associated with your pricing plan to determine your energy charges. Even if your usage stays the same, rate changes can affect your bill. TEP’s last change in the basic rate was in 2023, although energy surcharges were reduced two years in a row.

TEP also offers several pricing plans, including Time‑of‑Use and demand‑based options, which can reduce bills for customers who shift energy use to off‑peak hours.  Our Pricing Planner tool can help you decide which plan is right for you.