Simple Electricity Basics
for Outdoor Cooling

Choosing the best outdoor cooling options sometimes requires a little knowledge of basic electricity. You need to know if this outdoor fan or that portable air conditioner or that other cooler will work with your electricity supply. Product descriptions say 220 vac or 76W/.6 amps, but what does that mean?

Most outdoor cooling solutions use electricity: misting systems that use pumps, misting fans, outdoor fans, swamp coolers, and portable air conditioners all use electricity. Here’s how you can know if this outdoor fan or that portable air conditioner or that other cooler will work with your electricity supply and how much electricity it will use.

Here’s a brief overview of how electricity works and a few important definitions. At the end is a word picture to help you understand and remember how basic electricity works.

Anything electrical you buy should be compatible with your power supply. But a lot of people don’t realize that power supplies vary from country to country, and power needs vary from appliance to appliance. With more and more things being made and imported from more and more countries, it’s helpful to know how to make sure the two will go together.

The basic electrical information to look for on an appliance are its CURRENT, VOLTAGE and FREQUENCY ratings as well at its AMPS (ampere) and WATTS (wattage) ratings.

These things will tell you:

  • whether that electrical appliance will be compatible with your electricity supply
  • how much electricity that appliance uses


is the “AC” in:220VAC or the “DC” in: 12VDC

Power is supplied by one of two “Currents” — “Alternating” or “Direct”. The appliance and power supply must be working with the same kind of current. AC current (Alternating Currency) is the kind supplied by your local electric company. You might think of this as “long distance” current because it can travel very far along electrical lines. It may go through a power station and several transformers before it gets to your appliance.

DC current (Direct Currency) comes from a battery, usually powered by a car, truck, boat or recreation vehicle. With DC current the wires go directly from the battery to the appliance — no power stations, no transformers. Some appliances can switch their currency needs between AC and DC, and there are converters that can be purchased separately to convert between the currents.

VOLTAGE or “Volts” for short

is the “V” in: 220VAC or 2611W / 9AMP

Volts are the measurement of electricity’s force, or pressure. It measures how strong the current is that is supplied by the electric company to any one outlet, or how strong the current is from the battery. Voltage is a measurement of potential energy available, not how much is actually used.

The voltage to an outlet can be increased or decreased by changing the wiring. For example, a 110VAC outlet can be modified to supply 220VAC.

Many electrical appliances are dual voltage. By simply changing a switch they can be run on 110V or 220V, for example. Given a choice, outdoor fans will run better on higher voltages (more potential energy), especially if they need a long wire or extension cord to reach the power supply (picture a stronger force needed to push the electricity along those long wires).

There are a dozen or so voltages available worldwide. Voltage supplied varies from country to country. The United States and much of Latin America uses either 110V or 220V, depending on the wiring. 220V and 230V may be the most commonly used worldwide.

Many small appliances draw on the lower voltages in the 100s range, but these can generally be used only in the United States and much of Latin America where 110V is supplied. Larger and more powerful fans need higher voltages in the 200s range to work correctly.

There is some flexibility in voltage compatibility between an appliance and a power source –most electrical power systems have slight variations in voltage due to demand or other factors. A difference of 10 or so volts makes no difference, but large differences can damage your electric appliance.

HERTZ / Frequency

is the “Hz” in: 120V 60Hz

Hertz is the measurement of the electricity’s “frequency” or how quickly it “cycles”. The frequency most used worldwide is 50 hertz. 60 hertz is used in about 20% of the world including most of Northern, Central and Southern American countries, plus many Pacific Island nations and Saudi Arabia.

There are only two frequencies. There is no flexibility with frequencies. If an appliance works on one frequency it will not work on the other.

AMPERES or “Amps” for short

is the AMP in: 2611W / 9AMP

Amps measures the amount of electricity actually used. Electrical appliances need a certain amount of electricity to do their job. They draw that amount from the volts in a line. The “A” of “Actual” or “Amount” can help you remember the “A” of Amperes. Bigger, stronger appliances need more amperage, maybe 20 amps or more. Smaller appliances need less, often less than 1 amp. They both draw electricity from the same voltage supply (120V), but they each draw different amounts of electricity from that supply.

WATTAGE or “Watts” for short

is the “W” in: 2611W / 9AMP

The power of an electric appliance is measured in watts. Wattage tells you how much electricity works (converted to watts) to actually run the appliance. You can use the “W” of “wisely used” or “work” to remind you of “W” in “watts”. The number of watts listed on any appliance will tell you how much electricity the appliance “works” with.

One watt is about the amount of energy it takes to raise a 12 ounce can of soda 1 foot in one second. The power a 60 watt incandescent lightbulb uses could raise a 24-can case of soda 2.5 feet each second. Imagine lifting one case of soda onto a 2.5 foot tall table every second for an hour. That’s the mechanical effort required at the power plant to provide 60-watts of power for an hour.

Plugs and Outlets

The plugs on electric appliances are designed to prevent their being plugged into an outlet with an incompatible power supply. Plugs and outlets are rated by a company called NEMA (National Electrical Manufacturers Association) who standardizes them internationally. These illustrations show what the most common plugs and outlets look like.

NEMA 5-15 plug configuration
NEMA 6-20 connection configuration
NEMA 6-30 connection

The 5-15 (the first, on the left) is the kind you will see mostly in homes and offices – with the two vertical rods – and is designed for electrical appliances that draw up to 15 amps. The 6-20 (second, center) is also very common and is often in residential garages, offices and factories where more powerful electrical appliances that draw 20 amps are often used. The 6-30 (third, right) is for electrical appliances that draw 30 amps and is more commonly seen in factories, warehouses and areas where more powerful appliances are typically used. Of course, there are other configurations for appliances that draw even more power.

All plugs on outdoor electrical appliances have a grounding (earth) pin that helps prevent electrical shorts and fires.

For personal safety some units are fitted with a GFCI (Ground Fault Circuit Interrupter) that detects power fluctuations that might cause electrocution. The GCFI shuts off the power (“interrupts the circuit”) to an appliance when a dangerous fluctuation occurs.

Some newer appliances may have a LCDI (Leak-Current Detection and Interruption) plug. These detect any leaking current, which would happen if the cord was damaged or frayed, which could cause a fire.

Both GFCI and LCDI equipped plugs have “Test” and “Reset” buttons that are simple to check whenever you use your electrical appliance.

Estimating Electricity Use

Electricity use is determined by the amount of watts an appliance uses. When you buy electricity you are charged by the kilowatt-hour (kWh). Using 1,000 watts for 1 hour equals one kilowatt-hour.

1,000 watts are called a kilowatt. A kilowatt-hour (kWh) is equal to the energy of 1,000 watts working for one hour. Kilowatt hours are determined by multiplying the number of watts or kilowatts required by the number of hours of use. For example, if you use a 40-watt light bulb 5 hours a day, you have used 200 watts of power, or .2 kilowatt-hours of electrical energy.

You can use this formula to estimate any electrical appliance’s energy use:
Wattage × Hours Used Per Day ÷ 1000 ≡ Daily Kilowatt-hour (kWh) consumption

Here’s an example:
One portable air conditioner I saw uses 1,400 watts of electricity. If I wanted to use it for four hours a day I would be using 5,600 watts (1,400 × 4 ≡ 5,600), which is the same as 5.6 Kilowatt-hours (5,600 watts divided by 1,000 ≡ 5.6 kilowatts). I then need to learn how much my local electric company charges me for each Kilowatt-hour. My electricity costs $.10 US per kilowatt-hour. So this portable air conditioner will cost me $.56 U.S. in electricity each 4-hour day I use it, or 14¢ per hour.

To recap, you would need to use the wattage for the appliance you are considering, estimate how many hours a day you will use it and multiply those numbers together. Divide by 1,000 to get kilowatt-hours, then multiply the number you get by how much your electric company charges per kilowatt-hour.

I Don’t Understand Electricity!

A story about an outdoor fan to help understand

I personally have a terrible time understanding basic electricity. But I’ve had to learn in order to write some of the pages for this site. So I’ve put together this little story to help myself understand and remember.

The Characters

Picture a banking relationship between the banker power supply and the customer appliance. This may seem silly, but sometimes silly things can be the most helpful.

We will use the character of a “fan” (an enthusiastic supporter) to represent the customer / electrical appliance. It seems appropriate to use a fan since this site is about outdoor cooling, and one terrific cooling method that uses electricity is an outdoor fan. This fan happens to really love the outdoors. After all, it is an outdoor fan.

The bank represents the power supply. Its success depends on making loans from their “vault”, so there is some pressure from management to get that vault’s volts out and moving around.

This is not intended to be perfectly accurate but to help you get a picture of how these basic electrical concepts work. I hope it helps.

Here’s how I’m using some basic electricity terms in the story:

  • In our banking analogy, “Currency” is the same as electrical currency (same word without the analogy — how convenient!).
  • VOLTS is the amount that’s constantly supplied to the bank’s Vault. (The “v” in “Vault” can help you remember the “v” in “Volts”. In fact “vault” and “volt” kind of sound alike.) It also measures how much the fan needs to constantly have available.
  • Hertz relates to the “Frequency” of spending and lending cycles (again, same word).

The Plot

“Our fan is looking for a bank that uses the same currency as s/he does. In real life, everyone needs to agree on what kind of money or currency they are using and it’s no different here. Many banks have currency converters that will exchange the currency from one country to the currency of another. But this particular banking company uses alternating currency because it has many bank branches. Alternating currency lets them move it from one branch to another. There are also smaller banks that use direct currency, but these are strictly local banks. Our fan has been set up to work with alternating currency, so this fan may be able to work with this bank.

This local branch always carries 110 volts in its vault, supplied constantly by the main branch. Our fan works best with a steady supply of 120 volts, but the bank can make that adjustment so this is just about the right fit. 80 volts would not cover the fan’s needs, and the high fees of a bank that has 220 volts could break the fan. So this might work, but we’re not sure yet.

The fan needs to make frequent withdrawals on a 60 hertz spending cycle. Some banks work on the “50 hertz” lending cycle, so withdrawals would have to be less frequent. But this bank works on the “60 hertz” lending cycle, and that’s exactly what our fan needs. This relationship will work.

The fan makes actual withdrawals of 2 amps from the vault, but how it’s used shows how smartly the fan spends it. What does the fan do with those withdrawals? It wisely invests 240 watts, putting that energy to work to cool people down.”

Did you follow that?

I hope it made basic electricity a little more clear. I hope it will make it a little easier to pick out your next appliance — an outdoor fan, perhaps?