We know an air conditioner is a power hog, consuming at least a thousand watts per hour. Using your air conditioner non-stop can easily translate to high electric bills.
Would it not be awesome if you could lower your monthly electric bills by altering the way you power your air conditioning unit? Solar power offers a cost-effective way to use residential ACs. However, I am sure you have asked yourself, how many solar panels to run air conditioner?
Unfortunately, nobody knows how many solar panels you need for your setup because your system is different from others. However, this article will help you gain a clear picture of the number of solar panels to run air conditioning in your home.
- How Many Solar Panels for Air Conditioning Units?
- How Much Power Does an Air Conditioner Require to Cool the Home?
- Why Do ACUs Have Tonnage Ratings?
- How Many Solar Panels Does a 5-Ton ACU Need to Run?
- How Many Solar Panels Does a 2-Ton AC Need to Run?
- How Do You Account for Solar Panel Production?
How Many Solar Panels for Air Conditioning Units?
Determining the number of solar panel to run AC requires matching the solar panel’s wattage rating with the air conditioner’s power requirements.
For example, suppose you have a 3,000-watt central air conditioner. In that case, you need a solar panel capable of delivering at least 3,000 watts.
Most residential solar panels today can only produce anywhere between 100 watts and 415 watts. Hence, if you get a 100-watt solar panel, you will need 30 of these panels to run your air conditioner. Alternatively, you can install ten 300-watt solar panels to supply power to your air conditioner.
How Much Power Does an Air Conditioner Require to Cool the Home?
According to the US Energy Information Administration, air conditioning ranks fourth (8%) among the principal sources of energy consumption by American households. The first three are space heating (43%), other uses (21%), and water heating (19%).
Air conditioners consume at least 200 kilowatt-hours (kWh) per month, going as high as 1,800 kWh per month.
If you have a small compact window-type AC, the average power draw is 500 watts per hour. On the other hand, a larger window unit can use 1,440 watts per hour, while a medium-sized window AC consumes about 900 watts per hour.
A centralized air conditioning system might run as high as 3,000 watts hourly, especially during the summer. However, if you set the AC to fan mode only, you can reduce power consumption to only 750 watts per hour.
Hence, if you have a 500-watt AC running for eight hours every day, you can expect to consume 120,000 watts or 120 kilowatts per month.
Why Do ACUs Have Tonnage Ratings?
Knowing an air conditioner’s wattage rating does not give you information about its cooling efficiency. That is why many solar panel installers and air conditioning experts refer to an ACU’s tonnage rating. In general, the higher the tonnage rating, the more air volume the ACU can cool per hour.
However, it would still be best to check your air conditioner’s wattage and tonnage rating. For example, one 1-ton ACU might use 588 watts, while another 1-ton unit might require 751 watts. In this scenario, it would be best to get the 588-watt, 1-ton ACU.
How Many Solar Panels Does a 5-Ton ACU Need to Run?
If you have a 5-ton ACU, installing a single solar panel for air conditioning this size is insufficient. The highest wattage rating for a solar panel so far is 415 watts. A 1-ton air conditioner will require 1 kWh to 1.2 kWh.
Suppose you run your air conditioner for four hours when you need it the most, such as at noontime. A 1-ton air conditioner will consume up to 4.8 kWh (1.2 kWh x 4 hours) during this period. In that case, a 5-ton AC will consume 24 kWh (4.8 kWh x 5 tons) over four hours.
Let us also say you only have 300-watt solar panels. A single solar panel can produce 1.2 kWh over four hours, provided you have the ideal conditions. If not, you can expect the solar panel’s output to be less than its rated value.
We can use the above values to compute the number of solar panels needed to run a 5-ton AC. We must divide the AC’s power requirements by the solar panel’s energy generation. Hence, we get 20 solar panels (24 kWh ÷ 1.2 kWh = 20).
If you intend to use the 5-ton AC for five hours running on solar power, you must supply it with 6 kWh per ton. The AC’s power expenditure is 30 kWh over five hours. Hence, you will need 25 300-watt solar panels (30 kWh ÷ 1.2 kWh) to keep your 5-ton AC running on solar power for five hours.
Evidently, the higher the AC’s energy expenditure or consumption, the greater the number of solar panels you need to use.
How Many Solar Panels Does a 2-Ton AC Need to Run?
We can estimate the number of solar panels a 2-ton air conditioner needs. Multiplying the average AC power consumption per ton (1.2 kWh) by four hours will give us 4.8 kWh per ton. Since we have a 2-ton unit, the energy consumption is 9.6 kWh (4.8 kWh x 2).
A 300-watt solar panel delivers 1.2 kW over four hours. Hence, the number of solar panels you need to run a 2-ton ACU is eight (9.6 kWh ÷ 1.2 kWh).
What if you do not have a 300-watt solar panel that can power an air conditioner? What if the only available option is a 200-watt panel? In that case, this solar panel can only deliver 800 watts over four hours (200 watts x 4 hours).
We can recalculate our solar panel requirements by dividing 9.6 kWh by 0.8 kWh (equivalent to 800 watts). The result is 12 200-watt solar panels.
Hence, it is safe to assume that a solar panel’s maximum wattage rating can also impact the number of solar panel units you need to power your air conditioner.
If you decide to use the latest 415-watt solar panel, you will only need six solar panels. A single 415-watt solar panel can produce 1.66 kWh over four hours. When you divide the 2-ton ACU’s energy expenditure by 1.66 kWh, you will get 5.78 or six 415-watt solar panels.
How Do You Account for Solar Panel Production?
Some regions are rich in solar energy all year round, allowing them to produce solar power efficiently. You can determine the solar panel’s watt requirement by dividing your AC’s energy expenditure by your region’s solar production ratio, as follows.
- Southwest: 1.5 to 1.8
- West Coast: 1.4 to 1.8
- Mountain West: 1.3 to 1.6
- Southeast: 1.2 to 1.5
- Mid-Atlantic: 1.1 to 1.35
- Midwest: 1.1 to 1.3
- Northeast: 1.0 to 1.3
- Pacific Northwest: 1.0 to 1.15
Suppose you live in Arizona with a solar production ratio of 1.7, and you have a 3,000-watt AC. In that case, the adjusted wattage is 1.765 kWh (3,000 ÷ 1.7). Hence, you need six 300-watt solar panels (1.765 kWh ÷ 0.3 kWh).
Unfortunately, if you live in Rhode Island with a solar energy production ratio of 1.0, you will need ten 300-watt solar panels (3,000 watts ÷ 1.0 = 3,000 watts; 3,000 watts ÷ 300 watts = 10).
The answer to the question, how many solar panels to run air conditioner, depends on the following:
- The AC’s energy requirements
- The solar panel’s power generation capabilities
- Number of hours running the AC
- The location’s solar production ratio
Although there are other factors you can consider, these parameters should give you a rough estimate of the number of solar panels you need to run your air conditioner.