Electricity and Utility Costs

Electricity and Utility Costs - How much does it cost to run this?

Have you ever tried to understand how much it costs to use electricity to do something like charge your car or run your dryer? It's not super difficult to get lost in the weeds when trying to understand what the costs are. As a consumer, you may worry about the charge on your electric bill, or the environmental impact, or the amount of time it takes, etc. Even starting with the financial burden can be complicated. But with a little simple math (read: a four letter word that can trigger most people), and knowing your starting point, it's totally doable. So let's break out the shovels and dig into it, shall we?

Knowing Your Starting Point and Utility Cost

What is your starting point? First, let's talk about your starting point for what the utility company is billing you when you plug something in. For instance, in my area, the last time I checked, peak demand times are between 5-9 pm, M-Sa. That means electricity is going to cost a little more during that time because there’s more stress being put on the electrical grid. Families are coming home and turning on their ovens, washing machines, furnaces, dishwashers, then the water heater has to turn on to replace what’s being used, and so on. For this discussion, we’re assuming it’s not peak demand time. Just a standard $.155 (fifteen-and-a-half cents) per kilowatt-hour (kWh), which is roughly what it is in my region right now. The math we’ll cover has been rounded to the closest penny. Because utilities add up quick - you know the game.

What’s a Kilowatt-Hour?

Kilowatt-hours are an electrical unit you see on your electric utility bill and it’s the measurement the company uses to charge you. It’s a unit of work which represents how much generated power is being used by showing the amount of energy consumed. Imagine it is all based on a kilowatt being used to power something every hour. It’s a bit tricky because it’s a unit that doesn’t feel very much like a kilowatt, and even less like an hour, unless you use easy examples. An example would be turning on an oven that uses 9,000 watts (9 kilowatts or kW). Ignoring the cycles the oven goes through to reach and maintain an internal temperature, if you had it on for exactly one hour, you would theoretically be charged 9 kWh. Multiply 9 by $.155 and you just spent about $1.40 to run your oven for an hour.

I Keep Hearing How Inefficient My Space Heater Is

Another example would be a space heater. Say you set the thermostat on it to 72 degrees. To get your room up to 72 degrees, it runs for 15 minutes when you first turn it on. You look on the back of the heater and you see it consumes 1,500 watts. You need to convert watts to kilowatts, so that’s 1.5 kW. 1.5 kW consumed in 15 minutes (¼ hour) is equal to around $.06 (1.5 kW x $.155 / 4 = $.058). If the heater has to turn on every 10 minutes and run for 5 minutes, then that’s $.077 per hour after the first 15 minutes. Of course, this example assumes quite a bit, including about the perfectly insulated room in a house that has a constant temperature outside of it. Gets us there though. Usually it’d be more than six to eight cents an hour because of a lot of factors not covered in this article.

My Space Heater Doesn’t Have a Thermostat

Okay, so if your 1.5 kW heater runs nonstop for 14 hours from the time you get home to the time you get up to get ready for work, you’re maybe looking at 14 x 1.5 x $.155 = $3.26. That’s weeknights. $16.28 per week. If you assume the average of 4.3 weeks in a month, you spend over $50/month for one space heater. Weekends, you turn the fireplace on, because you know electricity is expensive and you remembered peak demand time probably means you’re spending more than that so you bury your head under your pillow. Maybe now’s not the time, but rates are probably going to keep going up. I know in the ten months since I originally wrote this article, it’s gone up almost 25% where I live, in the Pacific NW, where according to the EPA, we get around half of our energy from renewables .

Thanks For the Bad News. Where Else Am I Hemorrhaging Money?

Do you own an electric car? Of course you do, that’s why I wrote this article anyway. If you charge an electric car with your 50 amp charger, you can expect it to use some portion of that - typically 80%. Most residential chargers, such as the Tesla Gen 3 wall connector, are commonly put on a 50 amp breaker. Since the vehicle actually determines what the current flow will be, another estimation is necessary. Here, we say it’s best to assume you’ll get 80% of the max size of your circuit (even though looking at the booklet for installing a NEMA 14-50 outlet, which since they both would commonly be put on a 50 amp breaker, when you look in your breaker panel would be theoretically delivering the same electricity as the wall connector - Tesla says max output is 80% of the 80% = 32 amps). Depending on how long you need to charge your car after it drove you around, you’re looking at approximately $1.19-$1.49 (32-40 amps deliverable) per hour to charge the car. There is a difference in how much current is flowing through the wires over time because of how electric car batteries charge, but we’re ignoring that.

Actually, I Drive a Hybrid Plug-in.

So if you forget to charge the car overnight or you drive a certain distance between charges, you run on mostly gas, right? According to fueleconomy.gov, it’s a little less than twice as much money to run on gas only for the first 25 miles. Caranddriver.com reported in 2018 an Ioniq gets 39 mpg in Hybrid mode, which kicks in automatically when the car runs out of useable charge. 25 / 39 = 0.64. If you pay $4.00 per gallon of gas, it’s closer to $2.56 to drive the first 25 miles.

The car is equipped with an 8.9-kilowatt-hour battery, but won’t go below 20% charge. If you have to charge 7.12 (8.9 x 0.8) kWh, the cost to charge from your Level 1 (120V) cord is equal to 7.12 x $.155 = $1.10. Thus, don’t forget to plug that car in, even if you don’t expect to have time to charge it to full.

Assuming you use the 120V factory charger cord and you get 27 miles of driving from a full battery, cost can also be thought of in a different way. (Is “convenience cost” a thing?) If it takes 6.5 hours to charge with the Hyundai charger cord, you get 27 / 6.5 = 4.15 avg miles of range per hour of charging. You lose 4.15 miles for every hour the car isn’t charging. Going back to the Tesla wall connector, the Model 3 gets 37 miles for every hour it’s charging at 40 amps. We can safely say the convenience cost of not charging an all-electric vehicle is much higher than forgetting to charge your hybrid - plus, you still have the option of using gas when driving a hybrid.

ClipperCreek Charger Alternatives for the 2018 Ioniq

2018 Hyundai Ioniq PHEV Quick Reference Guide

Wow, That’s Nerdy and Helpful All At Once. You Also Mentioned the Dryer?

When you went out earlier, you had to stop and buy some fresh oranges. It started dumping rain and because today of all days there was a huge line, you need to dry your clothes. If your dryer consumes 5,000 watts on the hottest setting, you would expect to pay roughly $.39 during non-peak hours if your clothes are dry in a half hour (5 kW x $.155 x .5).

TIPS from the Journeyman

Every appliance that uses electricity should have a tag on it that shows several things: its UL listing (or not), the voltage needed to run the appliance, the wattage it consumes, input and output if it has a transformer, etc. Pay attention to that because it can literally pay to have knowledge.

Never run a space heater on an extension cord - always plug directly into the wall outlet. A power strip is better than an extension cord if you need to move it away from the wall outlet some distance, but that is still not as safe as plugging directly into a wall outlet. Here are some reasons why your plug can heat up. Also, leaving a space heater unattended can be unsafe. Check the plug every time you use it to make sure it’s in all the way and ensure it’s not discoloring the outlet or faceplate. Don’t be afraid to replace the heater. A $25 space heater is cheaper than a house. That’s not a cost anyone wants to have to calculate.

(Originally published in March 2022 with $.12/kWh numbers.)

(Note on authenticity - this article is AI-free. I am the only contributor, if you don't count links.)