Air conditioners are one of the most energy-consuming appliances in anyone’s home.
In fact, according to the department of energy, air conditioners alone use around 6% of all the electricity produced in the United States.
For this reason, many homeowners nowadays are looking to take their central air conditioners off-grid to reduce their electricity bills and save the environment at the same time.
But how many solar panels do I need to power AC?
Well, there is no short answer to this question, as there are many different factors to consider such as ac wattage, run time, geographical location, roof tilt, and many more.
However, in this article, we will provide you with a step-by-step guide to help you know exactly how much solar power you need to power your air conditioner.
Also, at the end of the guide, you will find a data table that contains the most popular ac sizes and how many solar panels to run air conditioner.
So without further ado, let’s jump right into the first step.
Step 1: Calculate Your AC Energy Consumption
The energy consumption of your AC varies depending on the size, energy efficiency of the device (A++, A+, A, B, C, D, E), and how many hours do you this device per day.
To calculate how many panels you need to power your air conditioner, first, you need to check your AC Wattage.
A. Wattage Of The Air Conditioner
You can easily calculate the wattage of your Air conditioner by checking the table near the power cord.
This table will have important information such as Wattage, Amp, Volts, Energy Efficiency of the AC, and many more.
What we need is the WATTAGE (Power Consumption) and it’s measured in Watt, Watt-hour, or Watt/hour, which is how many Watts your AC use for every active hour.
But What to Do If I Didn’t Find the Wattage Section?
Well, don’t worry, you can easily calculate your air conditioner wattage using this simple equation:
For instance, let’s assume that your air conditioner voltage rating is 220 volts and its amperage rating is 15 amp, then your AC wattage is 3300 or 3.3 kW.
In other words, your AC consume 3.3 kW of energy per hour.
What if my air conditioner power consumption is in BTU?
British Thermal Unit (BTU) is the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit.
In this case all you need to do is to convert it to watts by using this awesome calculator.
B. Calculate your AC Monthly Energy Consumption
First, we need to calculate the daily power consumption, which can be done using this simple equation:
For instance, your AC wattage is 3.3 kW/hour, and it runs 3 hours/day.
This means that your AC daily energy consumption is around 16.5 kWh/Day.
Now, we can calculate the monthly power consumption, which is 495 kWh (16.5 kWh/day x 30 days).
Step 2: Figure Out The Solar Efficiency In Your Area
Your solar panel total power output depends on many factors such as:
- How many hours of direct sunlight your panels get per day
- How intense is the sunbeam
- Roof tilt
- Azimuth
- The efficiency of the panel
- Heat resistance
- And many more
For this reason, in order to calculate how much power do you need to run AC, you need to figure out your area solar efficiency.
The easiest way to do so is to use the PVWatts tool.
PVWatts is a calculator developed by the National Renewable Energy Laboratory (NREL) that uses weather data to provide you with an estimation of how much electricity will your solar panel produce.
Here is how to use the PVWatts calculator:
- Enter your address and click Go
- Click Go to system info
- Fill in your information
- Scroll down and fill in your electricity rate
- Click Go to PVWatts results
- Voila!
Here are the month-by-month results for a 1-kW solar array system in my location:
Step 3: Size Your System
Because of global warming, most people turn on their air conditioner starting from March and all the way to September.
So the next step is to take the average power output of these months.
In my case, it will be:
This means that my 1-kW solar system will produce around 128.5 kWh/Month during this period.
As mentioned, our central AC system requires 495 kWh/Month, and a 1-kW solar array in my location will produce 128.5 kWh/Month.
This means I need to install a 3.85-kW solar system or around Nineteen 200-Watt solar panels to power my central air conditioner.
How Many Solar Panels To Run Air Conditioner?
| AC Type | Run time | Monthly kWh Usage | Solar System Size | Number of 200-Watt Panels | Yearly Savings |
|---|---|---|---|---|---|
| Room Air Conditioner (500 Watt) | 7 hours | 105 kWh | 0.8-kW | 4 solar panels | $166 |
| Room Air Conditioner (1000 Watt) | 7 hours | 210 kWh | 1.5-kW | 7.5 solar panels | $332 |
| Room Air Conditioner (1500 Watt) | 7 hours | 315 kWh | 2.3-kW | 11.5 solar panels | $498 |
| Central Air Conditioner (3000 Watt) | 7 hours | 630 kWh | 4.5-kW | 22.5 solar panels | $997 |
| Central Air Conditioner (4000 Watt) | 7 hours | 840 kWh | 6-kW | 30 solar panels | $1329 |
| Central Air Conditioner (5000 Watt) | 7 hours | 1050 kWh | 7.5-kW | 37.5 solar panels | $1661 |
Related Article: How Long Does it Take for Solar Panels to Pay for Themselves
Last Words
The number of solar panels needed to power an air conditioner depends on 3 different factors:
- AC wattage
- Run time
- Geographical location
And as promised, in this article, we provided you with all the information you need to calculate exactly how much solar power you need to power your air conditioner.
Do you have any further questions?
If so, please share your thought with us in the comment section below.
