Knowing how many solar panels to run an air conditioner isn’t a simple answer. There are many factors that you need to take into consideration.
From the size of the air conditioner to the solar panel’s power output, there are factors on both sides of the party.
We’re here to break down these factors, do some calculations, and end up with an answer depending on what kind of air conditioner and solar panel you have installed.
Solar Panels for Air Conditioning Units
When we talk about appliances being powered by solar energy, we often refer to solar panels as the primary supplier.
Through harnessing the sun’s natural energy, solar panels provide AC power to our appliances, providing a safe, renewable energy source.
The benefits to using this energy over something like burned fossil fuels are it reduces your carbon footprint, and you won’t constantly need to fill up on gas.
In terms of what you can power with solar panels, the sky’s the limit. But, aside from air conditioners, people wonder how many solar panels to charge an electric car and other power-hungry appliances.
Solar panels, in general, are just a really good investment, especially if you stay in an area with hot humidity and plenty of sunlight.
For your appliances at home, determining how many solar panels I need to power up the appliances isn’t too complicated as they pull a constant current.
In other words, once you know the power rating of an appliance in watts, you can find a solar panel that matches the wattage.
Appliances like fridges, freezers, and air conditioners aren’t as simple, however, due to them containing motorized compressors.
This means that the power they draw would vary and need to be averaged out.
An air conditioner would need around 1,200 watts of solar panels for each ton of cooling capacity. This is assuming the solar panel is exposed to 4 peak-sun hours per day.
If you want to use a battery instead of an inverter, a 100Ah battery is recommended per ton for each hour anticipated during the air conditioner’s running time.
The benefit of this is that it’ll allow your solar panel to power up your air conditioner when irradiance is low and provides a reservoir to supply the motor surge current.
Solar panel systems that are designed to run home appliances make use of an inverter to change the DC voltage produced by solar panels into usable AC for domestic use.
When we talk about a ton in air conditioning ratings, it’s a value representing the amount of cooling necessary to freeze 2,000 pounds of ice in one day.
Veterans in the world of air conditioning refer to it as a “short ton span.”
The bigger the value of the tonnage, the more air can be cooled each hour.
One ton is represented as 3.5 kW (kilowatts), meaning that a one-ton air conditioning unit will have a wattage of 3,500. If you figure out the kilowatts, you know how to calculate solar panel output in watts.
Both air conditioners and solar panels have a rule of thumb guideline for sizing the system. For instance, one of these rules states that an air conditioning unit will pull around 7A for every 1 ton of its cooling capacity.
However, this will change as the tonnage changes.
How Much Power Does an Air Conditioner Use
Every air conditioner uses a different amount of power. Therefore, to determine the power consumption, the BTU (British Thermal Unit) is an important variable in our calculations.
Let’s compare three different air conditioning units with three different BTU ratings.
A 5,000 BTU AC uses around 500 W, a 10,000 BTU unit uses around 1,000W, and a 15,000 BTU conditioner uses around 1,500W. Notice how there’s a 500W jump between them?
This constant jump remains mostly true, with it only differing from 100W on the days where it's not constant.
In terms of amps, it’s a bit different. A 5,000 BTU AC will run at around 41A if it’s plugged into a 12V battery hooked up to a solar panel.
If we use the same system we used in the previous test, the 10,000 BTU air conditioner will run at around 83A while the 15,000 BTU air conditioner will run at around 125A.
Questions to Ask Yourself
There are a few questions you need to ask yourself before you can build a solar system to power an air conditioner.
- How long will the air conditioner be running?
- Are batteries required to run your air conditioner? And if so, what type of battery is best suited for the solar system?
- What’s the size of your solar panel?
- Do you have an inverter?
Answering these questions before we can think about hooking up our solar panels to an air conditioning unit is critical in ensuring that everything runs smoothly.
Choosing to run your air conditioning unit using solar panels will also save you a good amount of money as ac units are responsible for a large amount of power consumption.
Checklist to Know How Much Solar Power You Need
The size of your solar panel or solar array solely depends on how much energy you intend to use daily.
If you want to use a battery, the size of the battery bank depends on how many days you want your energy storage to last during cloudy days.
The charge controller you need should properly manage the energy between your solar panels and battery banks.
Lastly, the inverter you need depends on what appliances you want to run off your system, and in this case, we want to power an air conditioner.
To know how to size out these components, you need to make a checklist of every appliance you plan to power. This is done by reading the power consumption rating found on the appliance and the output rating.
If you have the volts and amps, simply multiply them together, and you will have the appliance’s wattage.
Once you have the wattage of your air conditioner along with any other appliances you may want to power, list the amount of time you spend using them each day in hours.
We then take the output wattage and multiply it by the hours, and voila, we have a measurement called watt-hours.
If you just want to figure out the watt-hours of your air conditioner, multiply the two values and see how it relates to your solar needs.
We don’t want a solar panel that performs under our required watt-hours, so you must do proper research before purchasing a brand and installing a brand new solar panel.
How Many Solar Panels to Run AC
All air conditioning units have different efficiency ratings, meaning if we used their electrical kilowatt ratings as a comparison, it wouldn’t reflect their cooling power.
In other words, if we have 2 AC units that are rated at 1.5 kW, there’s a strong chance that they might not have the same cooling power.
For this, we look at the energy efficiency ratio, telling us how well an air conditioning unit cools.
The EE rating system is based on an outdoor temperature of 95 degrees Fahrenheit and an inside temperature of 80 degrees Fahrenheit.
We need to take the air conditioner unit’s British thermal unit (BTU) and divide it by the electrical rating of the unit in Watts. After this, you will be left with a ratio that’ll indicate the efficiency of the ac.
If you have an air conditioning unit that has an EER of 11, it falls under the category of being an efficient AC.
Anything below 11 and around 10 is recommended for countries or locations that experience hot, humid climates.
Another power rating that people in the ac market look at is the SEER rating. This takes into account an air conditioner's cooling capacity over a range of outside temperatures instead of fixating on one or two specific values.
The S in SEER means that the ratings are seasonal.
When the motor inside an air conditioning unit starts up, it pulls more current than when it runs continuously.
The value of the running current is always dependent on the load, but the surge, also known as the inrush current, is the highest amperage that the motor pulls.
Surge currents only last for a few seconds, and the heating effect on the wiring isn’t too drastic or significant.
However, your breakers and fuses would need to be sized accordingly so that they can accommodate a random surge without causing a power trip.
This has important implications for a solar system wanting to run an air conditioning unit.
For example, if your ac is running during the day without a battery being used as an energy reservoir, the solar panel's wattage rating would need to be big enough to supply the motor surge current of the ac.
Now that we’ve explored what happens in an air conditioning unit on the load side, we can investigate the supply side in depth.
Solar Panel Options
Keep in mind that these 100W air conditioners are small and are typically fitted onto a room’s window to keep a room cool.
If you use a weaker solar panel such as 100W one, then having an array of 2 to 4 solar panels will be sufficient.
Whatever the wattage of your ac unit, always ensure that your solar panel matches it. If it doesn’t, put together an array of solar panels until their total wattage exceeds the wattage of the ac unit.
But we need to look at the bigger air conditioning units that will require more power.
Let’s say we have an air conditioner that uses 4.9 Amps at around 115 volts. To get the wattage, we multiply those two values together, getting around 564W per hour.
The average running time for an ac during the day is 8 hours or a third of the day.
We would need over 2100 watts of power to keep a 565-watt air conditioner powered because we have to go with an off-grid solar panel that uses batteries.
If you want to run this air conditioner unit purely off of solar, you want to have that excess power stored in batteries.
However, if you have a grid-tied system where you are feeding power into the grid, the solar panels won’t work after a certain time. This will leave you powering your ac off the grid overnight and if it's overcast.
Another factor to consider is that you need so much power during those limited sun hours each day to provide enough excess power above and beyond the wattage on the ac.
Using the batteries will ensure that you have enough power to last you all day and night.
200W Solar Panel Review
While there’s no specific solar panel designed for an air conditioning unit or system, we recommend Shop Solar Kit’s 200w solar panel if you want to power up a smaller ac.
For a central air conditioning unit, you want to ensure that you have an array made up of these solar panels.
This monocrystalline, high-efficiency solar panel is built to last and can power up your batteries, appliances, and, most importantly, your 100W air conditioning unit.
Air Conditioning units aren’t the prettiest sight to behold when stacked up on the outside of your house, so having a solar panel that doesn’t look too pretty won’t do your home any good.
Fortunately, the 200W solar panel from Shop Solar Kit is a matte black design with an aluminum frame.
It comes with pre-drilled holes compatible with ground mounts and Z brackets, making it easy to install anywhere you please.
The solar panel weighs in at around 27 lbs, making it easy to pick up and carry should you need to relocate.
In terms of dimensions, we are looking at a 58x26x1.4-inch design, and these measurements, paired with the solar panel’s light design, make it easy to install on top of an RV.
This also gives you an idea of how many solar panels per acre you would need if you wanted to expand and add more.
The rigidness of the solar panel makes it built to last, being able to withstand challenging environmental conditions and ensuring that you get your money’s worth.
Staying true to its name, this solar panel has a maximum power output of 200W. It also has a maximum voltage of around 21V with a current of around 10A.
Outside of an air conditioning unit, you can power anything that doesn’t exceed the total power output of the solar panel.
But staying true to the topic of air conditioners, this solar panel can go on the road with you to power your RV’s ac.
However, an RV’s air conditioning system will be more than a 100W air conditioner you use in your room. So, it’ll be best to have an array on top of your RV.
Who Is It For
This solar panel is geared toward those wanting to power a smaller air conditioning system that doesn’t use an excessive amount of power.
These units are priced at around $240, giving you a lifetime of customer support and a 25-year limited power output warranty.
To put that price into perspective, the average price is around $10/square foot wanted to know how much solar panels cost per square foot. So you are getting a pretty good bang for your buck.
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