Thinking of installing a window AC? Or do you want to know how many watts a window AC uses? Nowadays, saving on energy costs is important, and a window AC is much more affordable than a central AC or split AC.
Window ACs are a great option because they require just a good window; they don’t take up a lot of space and can fit into compact places. They don't come with separate outer units; everything a window AC needs is inside one unit. Plus, they’re really portable.
Our guide has everything you need to know about using a window AC, electrical units, and using an AC with a solar generator. If you have a solar generator like the BLUETTI AC200P, that’s all you need to run your AC with the solar generator.
Key Terms: BTU, Watts, Running Watts, Rated Watts, Watt-Hours
BTU: Referred to as a British Thermal Unit, BTU measures the heating or cooling output of an HVAC system, like an AC, furnace, or heater. Simply put, 1 BTU is the energy needed to lower the temperature of 1 pound of water by 1 degree Fahrenheit.
Watts: This is the rate of energy consumption or production. We multiply amps by volts to find wattage: Watts = Amps x Volts.
Running Watts: This is the amount of continuous watts that keep an appliance operating. It’s the wattage that an appliance needs to function normally, representing the real consumption of electricity at any given time.
Rated Watts: This is the electricity consumed when the window AC unit is running at full cooling capacity.
Watt-Hours: This measures the watt consumption over a period of time. An AC that uses 1000W for 6 hours will have used 6000 watt-hours. Watt-hours = Watts x Hours.
How Many Watts Does a Window AC Use?
How many watts a window AC uses depends on a few factors, such as the size of the AC, the outside temperature (hot or moderate), and the room size.
A small window AC uses around 500 watts, while a medium-sized one uses 900 watts, and a larger window AC can use 1440 watts or more. An average window AC rated at 5000 BTU (or approximately 1465 watts) consumes 500 watts of energy at full capacity. It consumes 4000 watt-hours of power in 8 hours.
The table below shows the estimated wattage against BTU for 3 different window ACs over 9 hours:
| AC BTU | Estimated Wattage (Watts) | Daily Kilowatt-Hours for 9 Hours |
|---|---|---|
| 500 | 147 | 1.32 |
| 2000 | 586 | 5.28 |
| 8000 | 2345 | 21.10 |
How to Calculate the Power Consumption of a Window AC
Before powering an existing window AC unit with solar power, you need to find out the window AC power consumption. You can convert the BTU values into watts or multiply amps by volts. kWh is the unit your bill comes in. Follow the steps below to find your power consumption in kWh, and we will calculate the total cost based on the kWh value.
Finding Window AC Wattage
We can use two methods to find the wattage of a window AC.
BTU to Watts:
1 BTU = 0.29307107018321 watt-hours. Let us assume your window AC has a BTU rating of 5000 BTU/hour.
Watts = BTU × 0.29307107018321
5000 × 0.29307107018321 = 1,465.355 watts.
Multiply Amps by Voltage:
A device operating on 12.21A at 120V would consume:
Watts = Amps × Volts
12.21 × 120 = 1,465.2 watts (rounded to three decimal places).
Convert to Kilowatts and Kilowatt-Hours
Watts to Kilowatts:
kilowatts = watts / 1000
1,465.355 / 1000 = 1.465355 kW.
Kilowatts to Kilowatt-Hours:
Kilowatt-hours = kilowatts × hours
1.465355 kW × 6 hours = 8.79 kWh per day.
Total Cost of Power Consumption
Multiply kWh by the rate of electricity in your state. We will assume it is $0.12 per kWh.
Daily Cost = Energy consumption × Cost per kWh
8.79 kWh × $0.12 = $1.055 per day.
You can estimate the daily cost by looking at the amperes or the wattage. However, the BTU to kWh conversion gives us a much clearer and more accurate value.
Tips for Reducing Window AC Energy Usage
After determining your window AC’s power consumption, the next step is to adopt effective tips to reduce energy costs.
Regular Maintenance and Filter Cleaning
Regular maintenance and cleaning of the filter result in more efficient cooling. Your AC works more effectively when it doesn’t have to deal with blocked airflow or dirty vents. Always clean the filters regularly and ensure nothing is clogging them.
Additionally, don’t skip regular maintenance due to the added expense. AC technicians can fix worn-out electronic components, replace wires, and clean parts. All of this helps your AC maintain its cooling capacity.
Proper Installation
Make sure that your AC is properly installed. It should be level so that it drains correctly, and follow the user manual to place it in a way that avoids outside air intrusion. If needed, hire a professional for this job.
Avoid Direct Sunlight on Window AC
Ensure that your window AC outdoor unit isn’t installed in direct sunlight. Also, the room where you’ve installed your AC should have fewer or smaller windows to minimize sunlight and heat. Direct sunlight and a hot room increase the performance load on your AC, reduce efficiency, and increase power consumption.
Set a Suitable Temperature on the Thermostat
Instead of setting your AC at 24 or 26 degrees Celsius, set it to a comfortable temperature like 26 or 29 degrees. The lower the thermostat setting, the more power your AC consumes. Setting it a few degrees higher, between 26-29, will consume less electricity than keeping it at 24 degrees.
Room Setting
Make sure that all gaps, such as under the door and windows, are properly sealed to prevent warm air from entering. Additionally, you should use thermal curtains or blinds on your windows. This will help prevent sunlight from penetrating easily and keep the room cool.
Similarly, it’s a good idea to have ceiling fans in your room. Ceiling fans help distribute cold air and keep your room cooler even at a lower AC setting.
Programmable Stopping Timer
If your AC has a smart thermostat, you should program it to turn off when no one is in the room and maintain an appropriate temperature at all times. You can set it to turn off when you leave and start up again when you return home. Smart thermostats and programmable timers help you save on window AC energy costs and reduce your electricity bill.
Upgrade to a New AC
Is your AC outdated? If you’re serious about cutting down on energy costs, it’s time to say goodbye to your old AC. Look for newer models of window ACs with ENERGY STAR labels that are more energy-efficient and will lower your power consumption. Consider ACs with smart thermostats and programmable timers.
How Many Watts of Generator Do I Need for a Window AC?
With the ever-increasing cost of electricity and the likelihood of power outages, it’s wise to have a backup power option for your window AC. Instead of petrol or diesel generators, consider opting for solar generators.
Solar generators like the BLUETTI AC200P + 3*PV200 Solar Generator Kit are environmentally friendly, noise-free, and cost-effective in the long term. The system has a 2000 Wh capacity, 4800W surge capability, 17 outputs for multiple devices, and seven different ways to recharge, including AC, solar, or car power.
Whatever generator you choose should be able to handle the wattage of your AC, so it’s important to select a generator with a higher wattage than your AC unit. You can run a medium window AC unit with a 1000-watt generator; however, for a larger unit, you should opt for a 2000-watt solar generator.
Additionally, you need to consider the battery capacity, as you must account for power consumption over time. A battery capacity of 1500 watt-hours will run a window AC at 600W for only 2.5 hours (not 6 hours), so battery capacity is crucial.
After determining that your desired solar generator has a higher wattage than your AC unit (both starting and running watts), divide the battery capacity in watt-hours by the AC power consumption in watts to calculate the duration of time.
Time (hours) = Battery Capacity (watt-hours) / Power Consumption (watts)
If you want to increase the battery capacity of your current solar generator, you can look into the BLUETTI B300 Expansion Battery. It has a 2000W maximum load capacity, 100W USB-C, a USB-A port, and a 12V/10A car output, among other features. However, make sure your solar generator supports an expansion battery.
Final Thoughts
Now you know everything there is to consider before buying a solar generator for your window AC unit. Don’t have a window AC? Think again. Investing in a modern, ENERGY STAR window AC will reduce your energy consumption.
Pairing it with a solar generator is the icing on the cake. Even after going solar, you still need to regularly maintain and clean your AC and follow evergreen tips to reduce power consumption and live more energy-efficiently.
FAQ:
Q. Will a 2000-watt generator run a window air conditioner?
If your AC has a starting wattage below 2000 watts, a 2000-watt generator can run your window AC. Window ACs have a starting wattage that is 2-3 times higher than the running wattage, but that’s just the initial wattage needed to turn on. Always check your AC specifications to avoid overloading.
Q. How much electricity does a 10,000 BTU window AC use?
A 10,000 BTU AC typically uses around 700-1200 watts per hour when running. To find usage in kilowatts, multiply the wattage by the duration and divide by 1000. If your 10,000 BTU AC uses 1000 watts for 5 hours, it would consume 5 kWh of energy. Always check the AC specifications and consult your electricity bill for estimated appliance costs.
Q. Does a window AC use a lot of electricity?
Compared to central AC units, a window AC doesn’t use as much electricity. On average, a window AC requires 500-1440 watts, while a typical central AC uses 3500+ watts. However, a window AC can use more electricity on hot days, and continuous use can increase costs as well. If properly maintained, a window AC is a more affordable option.
Q. Does a window AC consume more electricity than a split AC?
Generally speaking, a window AC consumes more electricity than a split AC due to several factors. Split ACs have an advanced design and better heat exchange systems that allow them to cool a room quickly. In contrast, window ACs have all their components, such as the compressor, in a single unit, which can lead to inefficient cooling and higher power consumption.
