Portable Air Conditioner Running Cost (Ultimate Guide)

Here’s everything you need to know about portable air conditioner running cost. No fluff, just the facts.

My name is Daniel, I am an electrical engineer, and in this article, I am telling you all about the average running cost of portable air conditioners in different locations, for different models. You’ll find a formula to calculate the exact running cost of the portable AC you want to buy.

And if you stick around to the end of the article, I am telling you exactly what to do to reduce your portable air conditioner’s electricity usage!

Quick answer: The running cost of a portable air conditioner is around $25.20 a month for moderate usage (4h daily) and for the US-average electricity rate of 14 cents per Kilowatt-hour. You can reduce your portable AC running cost with a careful window setup and insulation.

But that’s only an average value. Let’s see how the running cost of a portable AC will turn out for you.

How much does a portable air conditioner cost to run?

First of all, the running cost depends on many factors. One is the duration you use your portable AC each day. Another is the electricity rate you pay, which differs depending on your location.

And of course, it depends on the power consumption of your portable AC.

Let’s have a look.

Hourly, daily, and monthly portable air conditioner running cost

Your portable AC running cost depends on how much you use your portable AC. If you use it twice the time, you pay twice the price.

The average electricity rate in the US is 14 cents per Kilowatt-hour.

Also, let’s assume an average power usage of your portable AC of 1500W. That’s a slight overestimation. Most ACs use around 1300W of power. The 1500W accounts for the high summer heat times, where your portable AC uses its maximum cooling capacity.

It’s always better to overestimate a little than to be surprised by an unexpectedly high electricity bill.

With an average power usage of 1500W and 14 cents per Kilowatt-hour, you pay 21 cents every hour you run your portable AC.

Here’s a table showing you an average portable AC’s running cost for an average electricity rate, for different durations.

Of course, you mostly don’t use a portable AC 24 hours a day for a whole month. They are noisy. And also, you are not always at home.

Even 8 hours a day is a lot when it comes to averages. On a free Sunday, you might turn on your portable AC for 8 hours continuously. However, just the day after, at work, you work overtime and get groceries and you need your portable AC only for 2 hours.

Because of all these out-of-house times, I am using the 4-hour value as the most applicable average portable AC running time for most people.

So, the result of this first section is:

Running a space heater costs you $25.20 a month on average.

Portable air conditioner running cost by state

The running cost of a portable AC unit depends heavily on your local electricity rate. If you have the option to improve rates (by switching providers), then I highly suggest doing that.

I collected a complete list of the current average electricity rates in all US states. For each state, I added the monthly cost of running an average 1500W portable AC for 4 hours a day.

As you can see, there are huge differences in the monthly portable AC running cost depending on the state you live in. In fact, in some states, you pay more than double other states’ rates.

The most expensive & cheapest states to run portable ACs

Especially Hawaii and Alaska pop out. They have incredibly high electricity rates. However, in freezing Alaska, you mostly do not care about air conditioning.

On the US mainland, New York, New Hampshire, and California are among the most expensive states. In each of those, you’d pay more than $40 on your monthly electricity bill just to run your portable AC.

A short reminder: The US average monthly portable AC running cost is around $25.

On the cheap and affordable end of the spectrum are (among others) Utah, Washington, Missouri, Montana, and Nebraska. In those states, the cost is 50% lower than in the expensive states. Here you pay only about $20 a month. With 23$, Texas is in the lower-middle field. 

It looks as if higher wage states are usually higher rates-states.

So, as you see, a very important indicator of your monthly portable AC cost is the location you live in. Where you live causes either significant savings or expenses as compared to the average. And you can hardly justify moving states just to reduce your portable AC expenses.

Luckily, there are other things you can control to save money while cooling your home. Keep reading and I’ll tell you how to improve your portable AC’s efficiency and get the most cooling bang for your buck.

Portable air conditioner running cost for different models

Before we look at cost optimization, let’s see whether portable AC running cost depends on the model you have.

Let’s have a look at the power consumption of the three most popular portable AC models:

I intentionally picked three ACs with different BTU ratings, found their wattages, and calculated the efficiency for each of them.

Before we look at the running cost, let’s first note one thing: We see that the power consumption (in Watts) directly increases with the cooling capacity of the space heater.

The amount of Watts a portable AC draws is one direct indicator of the running cost.

Additionally, in the third column, you can see how much cooling capacity (in BTUs) you get per Watt for each heater. The more BTUs you get per Watt, the higher the efficiency.

Interestingly, all portable air conditioners have roughly the same efficiency in BTUs per Watt. Which is around 10 BTUs per Watt.

Efficiency does not depend on the AC model

If one model was significantly more efficient than another, then the efficiency value would vary more.

But it is apparent that all heaters, regardless of brand and model, give you the same amount of cooling capacity per invested Watt. For me, that means, I don’t have to get the most expensive portable air conditioner. The running cost of it will be the same as for a cheaper one and I won’t get much more cooling out of it.

As a rule of thumb, it seems that you can estimate the power consumption of a portable AC by dividing the BTU rating by 10.

Now, let’s finish this section by looking at the exact running cost of the same portable air conditioners.

To calculate the running cost of each portable AC, I assumed the US-average electricity rate of 14 cents per Kilowatt-hour (kWh). You can see that running cost directly increases with the wattage. Wattage (as we’ve seen previously) directly increases with BTUs.

The brand and model of the portable AC do not matter. The higher the BTU number, the higher the running cost.

Nice to know: You pay on average $1.68 per 1,000 BTUs of cooling capacity per month.

How to calculate the cost of a portable AC?

Calculating the cost of running your portable AC is actually very simple.

Just do the following:

• Check your portable AC’s BTU rating. Divide it by 10. That’s approximately the average power consumption (in Watts) of your portable AC. Note that number.
• Check your personal electricity rate. Ideally, you get the value from your latest electricity bill. But as a rough estimate, you can also pick your state’s average electricity rate from the big table above. Note that number.
• Use this formula to get your personal hourly portable AC cost:
  Power consumption (in Watts) × Electricity rate (in Dollars per kWh) / 1000 = Your personal running cost

Ensure that you use the formula with your electricity rate in Dollars, not in Cents, eg. if you pay $0.20 per Kilowatt-hour, then use $0.20 in the formula, not the value “20” (Cents / kWh).

How to reduce Portable AC running cost

All portable ACs have a built-in thermostat to sense the ambient temperature and control the cooling power.

On the thermostat front panel, or using a remote, you set a target temperature. This target temperature is the temperature that you ideally want your room to have.

Then the AC takes care of your wishes.

Decrease power consumption through clever usage

You can reduce your portable AC’s running cost by setting realistic and moderate thermostat target temperatures. This ensures that your AC is running within its capacity.

If you set a rather moderate target temperature, just a few degrees below the current temperature, the AC will cool only for a short period and then switch to an energy-saving mode when the target temperature is reached.

In this energy-savings mode, the portable AC will wait until it senses an increase in the current room temperature again. Only then will it power the compressor again to cool the room.

That’s the magic of thermostats: They automatically turn on and off the device in order to reach the temperature you wish. Some thermostats, don’t even turn on and off the device entirely. Some use complex computations to find the optimum power consumption to reach the target temperature. But that’s another story.

Reduce average power consumption through moderate settings

If you use your portable AC with moderate cooling settings, the average power usage will be significantly reduced.

However, if you set a target temperature that is too low, your portable AC will run in maximum power consumption mode endlessly.

The main reason is a limitation of portable ACs: Because they are blowing air out through one hose, they create negative air pressure in your room. This negative air pressure sucks in hot air from neighboring rooms and from outside (through door and window gaps and anything else that is poorly insulated).

In this case, the hot air coming into your room cancels out the cold air produced by the portable AC and the temperature does not change.

This means, that every portable AC has a limit on how much it can cool. If you set a target temperature that’s below this limit, your portable AC will run on full power all the time causing a very high electricity bill.

The solution is simple. Don’t overwork your little cooling buddy:

Just by setting realistic, moderate settings, you can save up to 30-50% on your AC’s electricity bill.

Don’t expect a portable AC to cool an 86°F (30°C) room to 64°F (18°C).

Big fixed wall AC units can accomplish this. Your portable AC can’t.

Reduce AC power consumption through proper installation

First of all, make sure that your windows and doors are closed.

Then, ensure that your AC’s window hose kit is properly sealed. Check that there are as few gaps as possible.

I know that it is almost impossible to perfectly seal your window using the window kit you received together with your portable AC. At least this has been the case for me. All windows have different shapes and sizes.

So, when you get your portable AC window ket, it is usually a one-size-fits-all product. Or you ordered some custom-length window kit. But still, it does not fit perfectly. 

Nevertheless, carefully install the window kit and do your best to close as many gaps as possible.

Insulate the hose

Portable ACs always run in bursts of cooling (you can hear a change in sound when the compressor starts extracting heat, just like in a fridge). During that time, feel the exhaust hose of your portable AC. You notice that it feels very warm.

Even the fact that you notice it getting warm means that the heat re-enters your room. The heat that should leave your room through the exhaust hose leaks through the hose. Either it penetrates the badly insulating plastic material, or there are actual holes in the hose.

You can fix this using an additional hose insulation wrap.

Check that there are no holes in the hose. Holes are very easy to fix using regular duct tape. Or you can use a special insulating HVAC tape.

Are portable ACs as efficient as regular ACs?

I wish I could tell you portable ACs are as efficient as regular ACs, but most aren’t. Most portable air conditioners are single-hose models.

Single-hose portable ACs are not as efficient as regular ACs. 

The major downside of almost all portable ACs is that they come with one hose only to blow the heat out of your room. This one hose sucks in the air from your room. However, this creates a suction (negative pressure) in your room which sucks in the hot air from other rooms or even from outside.

This heavily reduces the efficiency when compared to regular ACs.

There is one type of portable AC that does not have this downside: Dual-hose portable air conditioners.

These portable ACs suck in air from outdoors, extract the heat, blow the cool air into your room and then blow the extracted heat out of your room. 

My favorite dual-hose portable AC is the Whynther ARC 14S (click to view it on amazon). It is more efficient than any single-hose portable AC. 

The second hose compensates the suction effect and gives us almost the same efficiency as a regular AC unit. The only downside a dual-hose portable AC has when compared to a regular AC is the length of the airways (hoses). To overcome the length of the airways, the fans have to be stronger and waste a part of the energy that could be used for cooling.

Dual-hose portable ACs are almost as efficient as regular ACs.

When to get a portable over a window or wall unit?

Portable air conditioners always come with a cost. While they are practical for moving them around the house wherever and whenever you need them, they lack the efficiency a “real” window unit or a wall unit provides.

I’d say you should get a portable AC if you don’t want to or you can’t install a regular AC your living space.

Also, a portable AC will do a perfectly sufficient job if you just want to cool down a regular-sized room occasionally. 

Whenever you want to spare yourself installation hassle, cost, and professional help, get a portable AC.

Conclusion

Portable air conditioners are heavy-duty appliances and need lots of power to cool your room. However, clever usage (through picking the right temperature), as well as a proper setup with hose insulation and a carefully sealed window will improve your portable AC’s efficiency.

The monthly running cost of a regular portable AC with moderate usage is around $25, which is a worthwhile investment. At least I’d rather pay $25 for a reliable cold breeze than melt in the high summer heat.