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A 5kw solar system is enough to run a medium sized house, but what about air conditioners? How many can you run and for how long? If you want to power your AC with this solar system, there are many options available.
A 5kw solar system produces up to 20kw a day and can run two 1.5 ton 15000 BTU air conditioners. This system can power a 2 ton split AC for up to 9 hours under ideal weather conditions.
How Many Air Conditioners Can a 5kw Solar System Run?
A 5kw solar system can generate up to 20kw a day, enough for a small to medium sized home. These systems have 17 x 300W or 16 x 320W solar panels and are bundled with an inverter and system monitor.
If you want to run several AC units in your home, use this formula to find out how many the system can run. This calculation also works for refrigerators and other appliances running on solar power.
AC hourly watt usage x runtime
A 5 star 1.5 ton split AC uses 1.5kw an hour. If you run it for 8 hours that is 12kw.
If you have a 3 star 1.1 ton window AC that uses 1.15kw for 9 hours, it will consume 10.35 kw.
In reality you probably won’t be running multiple large AC units at the same time. You will probably use portable window AC units in each room, but that will not be a problem for a 5kw solar system.
It comes down to the AC size and how many hours you run it. Most AC units run for at least 12 hours during summer.
If you have a 1.5 ton split AC that would push the system to the limit. This does not even account for the other appliances the system runs. But if you are on the grid this would not be a problem as you can always revert to electricity.
The following list shows the most commonly used AC units and their hourly power consumption. Multiply the figure by the running time to determine how many kilowatts it consumes.
Air Conditioner Power Consumption Comparison
Keep in mind these are just estimates. The power consumption of your AC will be different depending on the settings you chose. Refer to your instructions for details.
For more about EER and energy efficiency ratings, click here.
5 Star Split Air Conditioner
- 1 Ton – .99kwh
- 1.5 Ton – 1.5kwh
- 2 Ton – 1.7kwh
3 Star Split Air Conditioner
- 1 Ton – 1.08kwh
- 1.5 Ton – 1.5kwh
- 2 Ton – 1.9kwh
2 Star Split Air Conditioner
- 1 Ton – 1.15kwh
- 1.5 Ton – 1.7kwh
- 2 Ton – 2.2kwh
3 Star Window Air Conditioner
- 1 Ton – 1.15kwh
- 1.5 Ton – 1.6kwh
2 Star Window Air Conditioner
- 1 Ton – 1.25kwh
- 1.5 Tons – 1.74kwh
These are estimates based on standard settings. If you select a higher setting the system will consume more power. If your AC is not certified energy efficient it is going to use even more watts.
Whether you are on on or off the grid, make sure to buy an AC with a good EER rating. The savings you get will be substantial and frees up more power for other appliances.
How Long Will an Air Conditioner Run on a 5kw Solar System?
This is going to depend on the AC type, runtime and whether your home is on or off the grid. So let us take a look at each one.
If you want to run multiple AC units, keep the following in mind:
A 5kw solar system can produce up to 20kw a day. But the output will be shared by other appliances in your house. it won’t just be for the AC.
If you have a 2 ton split AC and it uses 1.7 kilowatts an hour, it can technically run for 11 hours. 1.7 kw x 11 = 18.7 kw, within the capacity of a 5kw solar system.
But that will only happen if the entire system is dedicated to the AC. If it runs other appliances like a coffee maker, microwave, toaster, refrigerator, the runtime will be shorter.
It really comes down to how many hours you run the AC, how many watts it consumes and how much of the solar system can be set aside for the AC. Because there are so many factors the runtime will differ from one case to the next.
If you run a 1.5 ton split AC for 9 hours a day it will consume 13kw. That leaves 7kw for other appliances assuming the system generates 20kw. However if you are on the grid you can go to electrical power if there is insufficient power.
When you are off the grid, make sure there are enough batteries not just for the AC but other appliances you want to run. List all the appliances you run and you will see how much power can be set aside for the AC.
Do I Need Batteries to Run an AC on a 5kw Solar System?
If you are on the grid, batteries are not required. But if you are off the grid, batteries or a generator is necessary.
A 5kw solar system can generate up to 20kw with 4 to 5 sun hours. Once the sun goes down, you need a storage system to store this energy.
If your home is tied to the grid, the extra energy goes back to the power company. This is added to your credit and you can access this anytime. This is how most solar powered homes in the US are set up.
The benefit of a grid tied home is availability of electricity. You can run everything on solar power. But if solar isn’t enough you can switch to electrical power.
AC units work best in grid tied homes because they use so much power. Even a large solar system is dependent on the weather, so expect production to drop during cloudy days.
Battery Requirements For Off Grid Homes
If you are off the grid, batteries are needed to store the energy so you can use it later when the sun goes down. How many batteries you need depends on your daily usage and the inverter input.
Majority of 5kw solar systems have a 96V to 120V inverter. If your system produces 20kw a day, you need a 6 x 200ah battery bank.
Lithium is the best choice for air conditioners. For this setup we recommend the Ampere Time 200ah 12V LiFePO4 batteries because they have a longer depth discharge than AGM.
This assumes you use half the solar system output during the day. If you consume more than half, you can settle for a 4 x 200ah battery bank.
The more power you consume in the day, the smaller the battery bank required. The batteries are there to store excess unused power, so the less energy left over, the fewer batteries needed.
Again you don’t need batteries if you are on the grid. The extra power generated by the solar array goes back into the system. But for off grid homes, you will want to save that energy in case you want to run the AC for extended periods.
How to Reduce AC Power Consumption
- Buy an energy efficient AC. This is the single most important thing that you can and should do. The difference between modern and old AC units is significant. The higher the EER rating, the less power it will consume.
- Turn the AC off at night. If your AC has been running all day, turn it off during the night. It is cooler any way. This will save energy and is good for the AC compressor.
- Insulation. Insulate your house so cool air does not get out. Your air conditioning unit will use less power if there is cool air in the house already.
- Replace the air filter. Dirty and clogged filters force an AC to work harder and consume more power. Have these cleaned or replaced by a technician, and performance will improve.
- Clean the ducts and vents. No long explanation needed here. Keep these clean and your AC will run
- better and more efficiently.
A 5kw solar system requires a considerable investment, but it is a good one for the long term. If you have a medium sized home and use an air conditioner regularly, 5kw will do just fine.