How much power does an RV AC use? A guide to RV air conditioners’ power usage

In this article, I aim to provide a clear understanding of the electricity consumption of RV air conditioners.

In order to do that, I’ll first explain the different aspects of your RV AC’s electricity usage that need to be considered, namely its Power Usage (Wattage) and Energy Consumption (kWh), and the difference and the relationship between them.

I’ll then discuss each of these aspects separately and show you how to determine them as accurately as possible.

Let’s dive in.

Understanding electricity consumption: Power vs Energy

To understand the electricity consumption of your RV air conditioner, you’ll first need to understand how that electricity consumption is measured.

There are 2 main units that matter the most when trying to measure electricity usage: kWh and kW, and although they look similar, they measure two different aspects of electricity, and should not be used interchangeably.

• kWh: This stands for kilo-Watt-hours and is equal to 1000 Wh (Watt-hours). kWh and Wh are the conventional units for measuring Electrical Energy. For example, we can say that an RV air conditioner consumes 10 kWh (or 10,000 Wh) per day, or a solar panel produces 1 kWh (1000 Wh) per day.
• kW: This stands for kilo-Watts and is equal to 1000 W (Watts). kW and W are the conventional units used to measure Electrical Power. For example, we can say that an RV AC unit is using 1000 Watts of power at a given moment, or, a solar panel is producing 120 Watts at a given moment.

The difference, or rather, the relationship between kWh (Energy) and kW (Power), is that Power measures the rate at which Energy is being transferred (consumed or produced). This relationship can be expressed as follows:

Energy (in Wh or kWh) = Power (in W or kW)  x Time (in hours)

For example, if a TV continuously uses 30 Watts of power and is left on for 10 hours, it could be said that the TV consumed 300 Wh of energy during those 10 hours (30 Watts x 10 hours).

If the same TV is only left on for 30 minutes (0.5 hours), it could be said that it consumed 15 Wh during that 30 minutes (30 Watts x 0.5 hours).

Learn more about Energy (kWh) and Power (kW), and the difference between them here.

There are 2 more units that measure electricity, which would be useful to know about. These units are Amps (A) and Volts (V), which respectively measure Amperage (Current) and Voltage (Potential).

Learn more about Amps and Volts here.

Now, there is a relationship between Power (Watts), Current (Amps), and Voltage (Volts), and this relationship is expressed as follows:

Power (in Watts) = Amperage (in Amps)  x Voltage (in Volts)

For example, if an air conditioner operates at 120 Volts, and is rated at 10 Amps, the power rating (wattage) of the air conditioner can be calculated as such:

Power (W) = Amperage (A)  x Voltage (V)

Power (W) = 10 A  x 120 V

Power (W) = 1200 Watts

Power (kW) = 1.2 kilo-Watts

Now that we’ve covered the basics, let’s dive into the electricity requirements for RV air conditioners.

How much power does an RV air conditioner use?

The amount of power that an RV AC uses will mainly depend on the Capacity of the air conditioner, which is measured in BTUs (British Thermal Units). The higher the BTU rating of the RV AC, the more power (watts) will be required to run it.

The typical BTU rating for an RV air conditioner is 13500 or 15000. Air conditioners of this capacity will typically have a running wattage of around 1300-1500 Watts and a starting (surge) wattage of about 6000-7000 Watts.

However, Class A RVs are bigger and therefore require a higher cooling capacity. In Class A RVs, air conditioners are typically rated at 27000 BTUs and use 3000 watts of power when running, and require up to 13000 Watts of power to start.

The following table provides estimates of the power and current requirements of RV air conditioners based on their BTU ratings:

BTU Rating	Avg. Running Wattage	Starting wattage	Avg. Amperage at 115-130 V(AC)
7000	700 Watts	2500 – 3500 W	6 Amps
10000	1000 Watts	4000 – 5000 W	9 Amps
12000	1200 Watts	4500 – 5500 W	10 Amps
13500	1400 Watts	5500 – 6500 W	12 Amps
15000	1500 Watts	6000 – 7000 W	13 Amps
27000	2700 Watts	11000 – 13000 W	24 Amps
30000	3000 Watts	12000 – 14000 W	24 Amps

Please note that the “starting wattage” represents the amount of power that the RV AC unit needs to start. This is a surge in power that usually lasts for less than a second but should be taken into consideration when sizing equipment, specifically, when sizing inverters.

Also, please note that the “Average Running Wattage” values provided in the table are still estimates, the actual power usage of your RV AC will not only depend on its capacity, but will also depend on the specific model and its efficiency.

Below I explain how you can determine the power usage of your RV AC unit more accurately.

How much power does your RV AC use?

In general, there are 3 methods through which you could accurately determine the power usage of your AC unit:

1- Use the Energy Efficiency Ratio (EER):

In the U.S., appliances usually come with an EnergyGuide label (yellow label). In the case of air conditioners, these yellow labels contain the BTU rating and an EER (Energy Efficiency Ratio).

Both of these ratings can be used to determine the power usage of the air conditioner:

Running Wattage (W) = BTU rating (BTU)  ÷ EER

For example, here’s an EnergyGuide label from a 10000 BTU AC:

The power usage of this particular air conditioner can be calculated as such:

Power Usage (Watts) = BTU rating (BTU)  ÷ EER

Power Usage (Watts) = 10000 BTUs  ÷ 11

Power Usage (Watts) = 910 Watts

As of 2023, most RV ACs have an Energy Efficiency Ratio (EER) of at least 10. So, If you can’t find the EER specific to your unit, divide your RV AC’s BTU rating by 10 and you’ll have a pretty close estimate of its power usage (in Watts).

1- Use the Amperage (A) and Voltage (V) specified by the manufacturer:

The specification label of your RV AC, which is usually stuck to the side of the outdoor unit on the roof, contains all the information you need to determine the power usage of your AC.

Once you find it, if it doesn’t already specify the power usage in Watts, look for the specified Amperage and Voltage.

The Amperage rating of the air conditioner will usually be specified in Amps (or A for short) under RLA and/or FLA.

RLA stands for Running (or Rated) Load Amps and refers to the maximum amount of electrical current (in Amps) that the compressor should draw when steadily providing the maximum output. For example, in the image above, you can see that the manufacturer specifies a 12.2 Amps compressor’s RLA.

FLA stands for Full Load Amps, and in this case, refers to the maximum amount of current that the air conditioner’s fan uses when providing the maximum output. For example, in the image above, you can see that the manufacturer specifies 3.4 Amps as the fan motor FLA.

Now, both the compressor and the fan draw current when the RV AC is running, so both the compressor’s RLA and the fan motor’s FLA should be used to calculate the power usage of your ac unit.

In our particular example, the total amp draw of the air conditioner is:

Total Amp Draw (Amps) = Compressor’s RLA  + Fan Motor’s FLA

Total Amp Draw (Amps) = 12.2 Amps  + 3.4 Amps

Total Amp Draw (Amps) = 15.6 Amps

Now that we know the amperage of the air conditioner (15.6 Amps) and the manufacturer clearly specifies 115 Volts and the Voltage of the unit, we can calculate the power usage as such:

Power (Watts) = Amperage (Amps)  x Voltage (Volts)

Power (Watts) = 15.6 Amps  x 115 Volts

Power (Watts) = 1794 Watts

According to these calculations, the air conditioner in our example should at most use 1794 Watts of power under full load.

What we’ve just calculated is the “continuous” power usage of the unit, which is the amount of power it uses in its steady state of operation. However, as previously mentioned, when the unit is initially turned on, it will draw a higher amount of power.

This amount of power that the RV AC uses when starting up can also be calculated using the Voltage rating of the unit (115 Volts) and the Surge Current specified by the manufacturer:

For example, in the specifications label of this AC unit, you can see that the manufacturer specifies 63 Amps as the “Compressor’s LRA”.

LRA stands for “Locked Rotor Amps”, and it indicates the amount of current that the compressor uses in starting conditions. Using this specification, the surge wattage of the RV AC unit can be calculated as such:

Surge Power (Watts) = Surge Current (LRA) (Amps)  x Voltage (Volts)

Surge Power (Watts) = 63 Amps x 115 Volts

Surge Power (Watts) = 7245 Watts

According to the specifications of this air conditioner, the unit should be expected to use up to 7245 Watts (7.245 kW) of power when you turn it on. Although this power surge is only momentary, it should still be taken into consideration when sizing an inverter that can run your RV AC unit.

Now, as explained at the beginning of this article, the power usage (Watts) of the air conditioner is only one aspect of its electricity usage. An even more important aspect is the Energy Consumption of the unit, especially if you’re planning on running the RV AC on solar or on batteries.

This brings us to the next section.

How much energy does an RV air conditioner use?

As mentioned above, the amount of energy that your RV AC consumes will mainly depend on the power it draws when it’s running, as well as the unit’s usage duration.

However, just like any air conditioner, the energy consumption of an RV air conditioner will also depend on other factors, such as:

• The outdoor temperature
• The indoor temperature setpoint
• The quality of the RV’s insulation
• The efficiency of the unit

Be that as it may, as a rule of thumb, the average RV air conditioner will generally consume between 0.8 and 1.5 kWh of energy per hour. For example, if you leave your RV’s air conditioner for 6 hours a day, the AC unit should consume between 5 and 9 kWh of energy per day.

To provide some more perspective, the following table estimates the energy consumption of RV air conditioners of different BTU ratings:

BTU Rating	Est. Hourly Energy Consumption	Est. Daily Energy Consumption (Assuming 8 hours/day of usage)
7000	0.45 – 0.6 kWh/hour	3.6 – 4.8 kWh/day
10000	0.6 – 0.85 kWh/hour	4.8 – 6.8 kWh/day
12000	0.75 – 1 kWh/hour	6 – 8 kWh/day
13500	0.8 – 1.15 kWh/hour	6.4 – 9.2 kWh/day
15000	0.9 – 1.3 kWh/hour	7.2 – 10.4 kWh/day
27000	1.6 – 2.3 kWh/hour	12.8 -18.4 kWh/day
30000	1.8 – 2.6 kWh/hour	14.4 – 20.8 kWh/day

The figures provided in the table above should give you an idea, but keep in mind that they are still estimates. You can, however, determine the energy consumption of your RV AC more accurately using the power rating (wattage) of the unit and its usage duration (in hours).

Let me explain.

As I’ve mentioned before, the relationship between Power Usage (Watts or kiloWatts) and Energy Consumption (Watt-hours or kiloWatt-hours), can be expressed as follows:

Energy Consumption (in Watt-hours) = Power Usage (in Watts)  x Usage Duration (in hours)

or

Energy Consumption (in kiloWatt-hours) = Power Usage (in kiloWatts)  x Usage Duration (in hours)

For instance, if a light bulb uses 50 Watts of power continuously whenever it’s ON, and is left on for 8 hours, the amount of energy that the light bulb consumes over those 8 hours is:

Energy Consumption (in Watt-hours) = Power Usage (in Watts)  x Usage Duration (in hours)

Energy Consumption (in Watt-hours) = 50 Watts  x 8  hours

Energy Consumption (in Watt-hours) = 400 Wh

Energy Consumption (in kiloWatt-hours) = 0.4 Wh

The energy consumption of an RV air conditioner can be calculated in the same manner. However, contrary to a light bulb, when the air conditioner is left on, it doesn’t necessarily run 100% of the time. The AC’s compressor turns ON/OFF relative to the temperature.

When the air conditioner is turned on, the compressor runs constantly until the set temperature is reached. The compressor then turns on and off in a way that maintains the set temperature.

The percentage of time for which the compressor is actually drawing power is referred to as the “Duty Cycle”, and the formula for calculating the energy consumption of the RV AC is:

Energy Consumption (in Watt-hours) = Power Usage (in Watts)  x Usage Duration (in hours) x Duty Cycle (%)

The duty cycle will vary depending mainly on the outdoor temperature; the higher the temperature, the longer the compressor is going to have to run, and the greater the duty cycle. However, as a rule of thumb, using a duty cycle of 80% should provide some good estimates.

So, as a rule of thumb, you could calculate the energy consumption of your RV AC using the formula:

Energy Consumption (in Watt-hours) = Power Usage (in Watts)  x Usage Duration (in hours) x 80%

For example, let’s assume that the power rating of your RV AC is around 1500 Watts and that you leave it on for 8 hours a day. The daily energy consumption of the AC unit can be estimated as such:

Energy Consumption (in Watt-hours) = Power Usage (in Watts)  x Usage Duration (in hours) x 80%

Energy Consumption (in Watt-hours) = 1500 Watts  x 8 hours x 80%

Energy Consumption (in Watt-hours) = 1500 Watts  x 8 hours x 0.8

Energy Consumption (in Watt-hours) = 9600 Watt-hours

Energy Consumption (in kWh) = 9.6 kWh

Now, if you’re looking to run your RV air conditioner on solar panels and batteries, I’ve written a couple of detailed posts about the topic. Here are the links:

• How much solar power to run an RV AC
• How many batteries to run an RV AC

However, before you go ahead and read those, please note that the energy consumption of rooftop RV air conditioners makes the proposition of running them on solar a little difficult and expensive.

So, I recommend you start by reading this article, in which I provide a few tips on reducing the energy consumption of your RV AC and suggest a different approach that should make the project cheaper and more realizable.