It might seem like a straightforward question. How is energy measured? After all, what could be simpler? The power goes on; the meter spins around and somewhere in the brooding under-caverns of Energy PLC, a bill oozes its way into existence.
The segue from conception to the mailbox takes place out of sight, but still, most of us have a broad idea of how that occurs.
But asking “How is energy measured?” is a little more involved than you might at first think. There are tariffs to consider sudden price hikes, and discounts. Estimated readings rarely rub shoulders with actual consumption.
And as for that bill-friendly metric of kilowatt-hours (kWh) well, it might not be exactly what you think it is.
So, Just How Is Energy Measured?
The short answer is, well, kind of short. Energy companies use a unit of energy known as the Kilowatt. More accurately, they measure energy consumption in Kilowatt-hours. The Kilowatt-hour(kWh) is a useful way of calculating the power consumption of appliances such as a TV, games console, or toasters.
One kilowatt-hour (kWh) is one hour of using electricity at a rate of 1kW. The electricity company tallies up how many kWh you’ve consumed and then calculates your bill accordingly.
What is a kWh?
Ok, but how much is a kilowatt? And what is a watt when it’s at home, anyway?
Well, unsurprisingly, a watt is a unit of energy. Named after British engineer and inventor James Watt, it’s not, truth to be told, a tremendous amount of energy. It amounts to only 1/746 of horsepower, and for that reason, it's often measured in Kilowatts instead. One kilowatt equals 1,000 watts.
Of course, that’s still quite an abstract concept to get your head around. Saying watt is a fraction of a horsepower tends to lead to more questions such as “What is horsepower?" And that won't do. Not when the task set is to answer “How is energy measured?”
It might be helpful then, to think of it in terms of appliances.
The Appliance of Science
The air conditioner is probably the most energy-hungry appliance you have in your home. Still, since not everyone has an air conditioner, let’s take a look at the number two spot. Enter the refrigerator, stage left.
Old-style refrigerators used to gobble up a whopping 1,400 kWh per year. And let's face it, that’s an awful lot of watts. Thankfully, modern fridge-freezers are a lot more energy-efficient. A typical apartment size fridge consumes around 350 kWh per year.
That’s a big difference and is one of the reasons why manufacturers are quick to highlight such energy-saving prowess. At least, they do so whenever they try to convince you to part with your older model.
But what about those items scattered around the house that only advertise power drain in terms of wattage? How do we figure out how much they cost?
Well, that’s where the math comes in.
Let’s take a lava lamp. Chosen at random for no good reason other than the fact that we know what wattage bulbs they use, this bastion of 60s illumination is something of a known quantity.
The first step is pretty simple, calculate the watts the lamp uses per day. All we need to do is multiply the wattage of the device by the number of hours you use it. Three hours seems a not unreasonable amount of time to bathe in the fuzzy illumination of melted wax globules.
That gives us a figure of 75 watt-hours per day. Of course, as already discussed, we need to convert that into kW. Dividing 75 watts by 1, 000 takes us to 0.075 kWh per day. Multiplying that figure by 30 gives us a value of 2.25 kWh per month. Yes, even in a leap year.
Now, all we need to do is figure out how much that costs.
Converting kWh to Dollars
Converting energy into its cash value sounds like alchemy, but as with the conversion of watts to kWh, it’s relatively straightforward.
There are, however, several factors at play, all of which need taking into account. The cost per kWh fluctuates over time and at any rate, differs from provider to provider.
There are fixed-rate plans, variable plans, green plans, and cancellation fees to consider. Some companies offer other incentives too. It all depends on which energy plan you go with, which in turn, depends on where you live. At any rate, shopping around is an excellent idea.
There are far too many energy companies for this little, “How is energy measured?” overview to cope with so let’s settle instead for some benchmark figures.
The average price as expressed in terms of cents per kWh fluctuates from state to state. For example, residents of Connecticut paid 23.35 cents per kWh in May 2019 while over in the Evergreen State, bills clocked in at only 9.81.
The differential stems partly from proximity to a fuel source and partly from topography. Hawaii’s wince-worthy rate of 33.43 best exemplifies local price differentials.
Still, the average price for Americans stood at 13.32 cents as of May 2019 for residential properties and 13.15 for commercial properties.
Lava Juice Redux
That allows us to calculate how much our fictional Lava Lamp costs the average American. The answer is 29 cents per month. Or, if you happen to live in Hawaii, just shy of 75 cents. It does seem a little unfair, but then they do have some fantastic beaches.
Our 80s era refrigerator, on the other hand, would cost the average American closer to $15 a month The $40 a month it would cost to run such an energy-inefficient beast of an icebox is too painful to consider.
Any discussion on tariffs then is an important one. Doubly so considering the topic here is not only "How is energy measured," but, also the natural segue that follows: "How might it cost less?"
Sites like MakeTheSwitchUSA are of great help here. By selecting your state and your current provider, it’s possible to take a look at all the options currently available. The price, as you’d expect, comes in the form of cents per kWh.
But other pertinent information is present as well. The length of any fixed-term contracts, cancellation fees that may, or may not apply alongside other special offers such as cashback. There’s also the option to filter for green tariffs.
Speaking of which.
It’s so Easy Being Green!
For the environmentally minded, a green tariff is something of a must. In recent years, 100 percent renewable energy has fallen from an expensive luxury into the lap of an affordable lifestyle choice. So you can absolutely consider it.
Clearview energy, for example, offers a rate of 10.29 cents per kWh for their 100 percent green plan making it cheaper, in that zip code at least, than most of the competition.
That makes it more than a little tempting for some.
Of course, not everywhere currently has access to green energy. But new programs roll out all the time. So, keeping an eye out for them is another one of those really great ideas.
How to Cut Down on your Consumption
Still, although green tariffs might end up saving you a few bucks, or at the very least help ease your conscience, the question of saving money stands. A smart home energy monitor might be just the thing you need.
All such monitors provide a rundown of electric usage in real-time, although others go one step further. Some, when combined with an associated companion app, provide metrics in the form of, dollars spent and even C02 produced.
A great way to ensure you keep an eye on those kWh to be sure.
But we don't have to stop with mere observation. Since we now know, thanks to this "How is energy measured?” guide that it all boils down to watts, it’s easy to see where the next step takes us. You just need to use fewer watts.
There are many opportunities to do so.
While our by now long-suffering lava lamp needs a traditional bulb to get things going, for other light sources energy-saving measures are a must.
The term watt-equivalent refers to bulbs that shine bright while using less power. Thus, a 60-watt equivalent bulb from Tenergy illuminates an equivalent of a 60-watt incandescent bulb but only consumes 9 watts of power.
And that’s not all. Installing night lights, fitting cooling thermostats, or even just buying a couple of surge protectors that allow you to isolate switches for appliances are a big help. All of those things help reduce your wattage and save you money on your bill.
So there we have it. How is energy measured? Why in terms of how much you use, of course. And sure, that seems like a fairly obvious point to make, but it’s easy to see why it so often eludes us. Because so many of us take power for granted.
It’s something that we’ve used our entire life and stopping to think about where it comes from is the first step towards using it more responsibly.
Checking the wattage of an appliance is often every bit as important as the base price. Power-hungry gadgets usually cost more than their less hyperactive brethren in the long run.
So we know what to do, know what to check, and hopefully, now realize that sleeping in the comforting glow of a 75 watt-hour lamp might be good for the soul.
But it’s far from ideal for the wallet.
Do you have any thoughts to share? Sound off in the comments below.