How Many Solar Panels to Run an Air Conditioner

If you ask the question how many solar panels to run an air conditioner, you will get different answers. There are a lot of variables involved so there is no single correct answer. Factors to consider include the AC power requirements, solar panel size, energy efficiency rating (EER), and how long you will use the AC.

You need five 350W solar panels and 5 hours of sunlight to run a 1500 watt air conditioner. A 200ah battery bank must be connected to the solar panels to if you want to run the AC at night.

This example uses a portable AC and does not account for energy efficiency ratio. Most window air conditioners have a cooling capacity of 3500W, with larger units up to 1440W. With the compressor off and running on fan, the power requirement drops to 750W. A 5 energy star AC uses less watts too. With these different numbers the calculations will have different results.

How Many Solar Panels are Needed to Run a 1 Ton Air Conditioner?

To run a 1000W AC you need six 250W solar panels. The quickest way is to divide the air conditioner watts by the solar panel watts you will use. 1500 / 250 = 6.

A 550 BTU/1500W AC consumes 7500W for those five hours. With five 350W solar panels it is possible to get 8750W, more than enough to offset the energy loss incurred during absorption. It does not have to be 350 watts as long as the total is 8750 watts. You could for instance, use several 320W Renogy Solar Panels and your Air conditioner will run.

But that is a general calculation and does not include factors like energy efficiency and how many hours the AC will be used. You need a more precise method like the one below.

A 1 ton AC consumes around 3500W, but with an energy efficient ratio of 3.1, this figure goes down.

3500W / 3.1 energy efficient ratio = 1129W

Assume the AC will run for five hours.

1129W x 5 = 5645W

So a 3500W AC with a 3.1 energy efficient ratio (EER) requires approximately 5700W of solar panel power. Round that off to 6000W or four 350W solar panels with 5 hours of sunlight available. You can also opt for eight 200W solar panels or any combo as long as the total is 7000W. You want that extra 500-1000W buffer for cloudy and overcast days.

The energy efficiency ratio is very important. While 3.1 is used here, the higher the EER the better. If you can get an AC with an 8.5 EER, power consumption goes from 1129Wh to just 411Wh or 2000W for 5 hours. You can run an 8.5 EER AC on three 200W or two 300W solar panels.

Aside from energy efficiency, the number of hours you run the AC and sunlight hours available are crucial. The longer you run the AC, the more solar panel power is required. This needs to be balanced with how any hours of sunlight are available too.

How Many Batteries Do I Need For a 1 Ton Air Conditioner?

So far the calculations have focused on solar panel requirements for an air conditioner. But to be self reliant you need a battery. With a battery the solar panel can store energy for later use. You can use the stored energy in the battery to run the AC at night for instance. Or you can run the AC on the battery and let other devices / appliances use the solar panel.

To find out the battery capacity requirement, divide the AC watt power consumption by the battery volt. In our example above the AC uses 5645W for 5 hours. With a 24V battery:

5645W / 24V = 235ah

So a 235ah capacity battery is needed for a 1 ton AC. Note that while we used 24V, other batteries use 12V, 48V etc. Use the volt figure that applies to your battery.

But what if our 1 ton AC has an 8.5 EER? From 5645W, the number drops:

5645 / 8,5 = 664W

664W / 24V = 27.6

Instead of 235ah you just need a 27.6ah battery capacity for the AC if you use a 24V battery. This is why you always have to check the EER of an AC, of any appliance actually.

Lithium ion batteries like the Lossigy 300 12V are best suited for air conditioning units, but lead acid batteries are going to work fine with an AC too. Keep in mind that the battery should only be used at 50% of its capacity. Recharge the battery when it reaches 50%. This is important especially if you’re using it with an AC.

Just as you would add 10%-20% to the total power for the soar panel, you should buy a higher battery capacity. Ratings for solar panels and batteries always assume optimum conditions, but you have to be prepared for days when it is not.

How Many Solar Panels Do I Need to Run a Portable Air Conditioner?

Portable air conditioners are among the most energy efficient in the industry today. You can buy a 5000 BTU portable AC that consumes only 550Wh. Run it for 6 hours and you get 3300W. With 5 hours of sunlight (we are going with the minimum here) a 700W solar panel will be enough.

A portable AC is a popular option among solar power users and RV owners. With is low energy use and portability, it is a good option if you want to be energy efficient with solar power.. As technology improves, expect more efficient portable AC units to appear.

The biggest drawback with a portable AC is its limited capacity. You can only use it in a room or another confined area. The solution is to install multiple portable AC systems or just get a large window or central unit. if you want to use an inverter to run portable ACs, this guide can help.

How Many Watts is Needed to Run a 5 Ton Air Conditioner?

A 5 ton AC requires 17520W. But again, that figure will go down once you factor in its EER. Going with an 8.5 EER:

17520W / 8.5 = 2061W

That is 2061 watts per hour. Multiply by 5 and you have 10305 watts for a 5 hour running time. A 5 ton AC requires six 400W solar panels to run for 5 hours with 5 hours of sunlight.

You can use this same method for any AC size. In fact things are even easier now as most AC units display their watt usage with the EER factored in. Now you can use the figures given to get an idea of how many solar panels are required.

What about Solar Powered Air Conditioners?

We cannot talk about AC units and solar panels without bringing up solar powered air conditioners. This has been the goal of the solar industry. While there have been great strides made the past few years, pure solar powered AC units are not yet widely available.

There are two reasons why solar powered AC units have not taken off yet. First, solar energy is only accessible during the day. If you want to run the AC at night, you need a storage system to store solar power. That is where batteries come in. Unfortunately, AC units consume a lot of power

You need a good sized battery to store energy for reserve. While the cost of batteries have gone down, it is still quite expensive if you purchase a higher capacity model. More so, that high capacity battery will only be used for storing AC energy. If you want to run other appliances and devices on solar power, you need a separate battery.

This applies to the solar panel as well. Throughout the calculations made here, the solar panel is used only for the AC. That is not practical for RV owners and anyone using solar power. The panels are used for a variety of appliances and devices. Imagine having dual 400W solar panels but being unable to use it on anything else except the AC unit.

Unless your home is completely solar powered, an AC unit rarely runs on solar power. AC units on RVs are small or hooked up to electrical power. The situation is similar to the refrigerator, another power hungry appliance.

Fortunately, development of solar powered AC units are ongoing. Whatever shortcomings and technological limitations being faced, they will be overcome in the future. When that time comes, you can expect those units to be even more efficient in using solar panels and batteries.

Conclusion

Air conditioners are still power hogs, but thanks to energy star efficiency, it’s been greatly reduced. As can be seen from the calculations here, consumption with an energy star complaint AC is half of a non compliant unit. This makes it easier to operate one of these on a solar panel, so expect their use to increase in the near future.