Thinking about running your central air conditioner with a generator?
Our detailed guide simplifies the process. Learn to calculate the precise generator size, ensuring your home stays cool without hiccups.
Enjoy a comfortable and uninterrupted summer.
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What Size Generator Do I Need To Run Central Air Conditioner?
For a central air conditioner, you need a generator offering at least 3500 watts of starting power and 3000 watts of running power per ton. A 3-ton or 36,000 BTU AC requires a generator with at least 10,500 watts starting and 9,000 watts running.
Generator size chart for different AC sizes:
| AC Size (Tons) | AC Size (BTUs) | Starting Wattage (Watts) | Running Wattage (Watts) | Generator Size (Watts) |
|---|---|---|---|---|
| 1.5 | 18,000 | 5,250 | 1,750 | 6,000 |
| 2 | 24,000 | 7,000 | 2,333 | 8,000 |
| 3 | 36,000 | 10,500 | 3,500 | 12,000 |
| 4 | 48,000 | 14,000 | 4,667 | 15,000 |
| 5 | 60,000 | 17,500 | 5,833 | 18,000 |
For small central AC (up to 3 tons) we recommend to use DuroMax XP13000EH Dual Fuel Portable Generator.
And for large central AC (from 4 tons) we recommend using Generac Standby Generator.
Different Types of Generators Suitable for Running Central Air Conditioners
There are three main types of generators for running central AC.
Portable Generators
Portable generators are like helpful friends. They come over when you need them. They’re easy to move and can work with many fuels.
That means you can use gasoline, diesel, or even propane. But there are some things to watch out for. These generators can be loud.
Your neighbors might not like the noise. And they can make the air dirty. That’s not good for breathing. They also need regular care. Just like a pet! If you pick this type,
Make sure it can handle all your electric things. A transfer switch is a must. It’s a tool that keeps things safe.
Inverter Generators
Inverter generators are like fancy gadgets. They’re a bit more modern. They’re close in size to portable ones. But, they have magic inside.
This magic changes the power to make it smooth. That’s great for things like air conditioners. These generators adjust their speed.
So, they use less fuel and make less noise. But there’s a downside. They cost more money. They also might not power everything you need.
When picking this type, check its power. Also, a low-oil shutdown feature is good. It turns the generator off if the oil is too low.
Standby Generators
Standby generators are like superheroes. They’re always ready to help. They sit outside your house. If the power goes off, they turn it on by themselves.
They can use natural gas or propane. They can power everything in your home. But, these heroes come with a big price tag. You need experts to set them up.
They also need regular check-ups. They can’t be moved. So, if you move houses, they stay behind. If you pick this type, look at its power.
Also, a cooling system is a must. It stops the generator from getting too hot.
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Calculating the Exact Generator Size for Your Central Air Conditioner
Understanding BTU and Wattage
BTU stands for British Thermal Units. It measures heat. Wattage measures electricity.
To find out how much electricity your air conditioner uses, you can convert its BTU to watts. Multiply the BTU by 0.293 to get the wattage.
If your air conditioner is 24,000 BTU, its wattage is 7,032. This is a crucial step. Knowing your air conditioner’s wattage helps you pick the right generator.
Consideration for Start-up vs. Running Wattage
Every air conditioner needs more power to start than to keep running. This start-up power can be three times the running power.
If your air conditioner uses 7,032 watts to run, it might need 21,096 watts to start. Generators also have two power ratings.
Surge rating is the maximum power for a short time. Continuous rating is the power for a long time.
Your generator’s surge rating should be more than your air conditioner’s start-up wattage. Its continuous rating should be more than the running wattage.
Importance of a Buffer or Safety Margin
It’s wise to add extra power to your calculations. This extra power is a safety margin. It covers errors or unexpected power needs.
You may want your generator to run your air conditioner, a fridge, a TV, and some lights. First, add up their wattages. This sum is 7,982 watts.
Add a 20% safety margin. The total becomes 9,578.4 watts. This is your safety buffer. It ensures your generator can handle all your devices safely.
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Factors to Consider When Choosing a Generator for Your Air Conditioner
Here are some factors that you should think about:
Total Electrical Load
The first factor is the total electrical load that you want to run with your generator.
This is the most important factor that determines the size and type of generator that you need.
You should make a list of all the appliances or devices that you want to power with your generator and find out their wattage ratings.
You should also consider their start-up wattage and running wattage, and add them up accordingly.
You should also add a buffer or safety margin of about 20% to account for any errors or fluctuations.
Efficiency of the Air Conditioner
The second factor is the efficiency of the air conditioner that you want to run with your generator.
The efficiency of an air conditioner is measured by its SEER (Seasonal Energy Efficiency Ratio), which is the ratio of its cooling output (in BTU/h) to its energy input (in watts) over a typical cooling season.
The higher the SEER rating, the more efficient the air conditioner is.
The more efficient the air conditioner is, the less power it needs to run, and thus, the smaller the generator you will need.
You can find out the SEER rating of your air conditioner by looking at its label or checking its manual or manufacturer’s website.
For example, if your air conditioner has a SEER rating of 14, it means that it produces 14 BTU/h of cooling for every watt of electricity that it consumes.
Generator Fuel Type
The third factor is the fuel type of the generator that you want to use to run your air conditioner.
Different types of generators use different types of fuel, such as gasoline, diesel, propane, or natural gas.
Each type of fuel has its own advantages and disadvantages in terms of availability, cost, storage, performance, noise level, emissions, and maintenance.
You should choose the fuel type that best suits your needs and preferences.
Noise Level
The fourth factor is the noise level of the generator that you want to use to run your air conditioner.
Generators can be very noisy, which can be annoying for you and your neighbors.
The noise level of a generator is measured in decibels (dB), which is a unit of sound intensity. The higher the decibel rating, the louder the generator is.
You should choose a generator that has a low decibel rating or one that has a muffler or a sound enclosure, which are devices that reduce the noise of the generator.
Location and Ventilation
The fifth factor is the location and ventilation of the generator that you want to use to run your air conditioner.
Generators need to be placed in a safe and secure place, away from any flammable or combustible materials, such as gasoline, wood, paper, or cloth.
They also need to have enough space around them for air circulation and cooling.
They also need to have a proper exhaust system that vents the harmful emissions away from your home and the environment.
You should choose a generator that has a carbon monoxide detector, which is a device that alerts you if the carbon monoxide level in the air is too high, and prevents poisoning or suffocation.
Price and Budget
The sixth factor is the price and budget of the generator that you want to use to run your air conditioner.
Generators can be very expensive, both in terms of initial purchase and ongoing maintenance.
You should choose a generator that fits your budget and offers good value for money.
You should also consider the operating cost of the generator, which is the amount of money that you spend on fuel, oil, filters, spark plugs, batteries, and other parts and accessories.
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Warranty and Brand Reputation
The seventh factor is the warranty and brand reputation of the generator that you want to use to run your air conditioner.
Generators can be very complex and delicate machines, and they might break down or malfunction at some point.
You should choose a generator that has a good warranty and customer service, and that comes from a reputable and trustworthy brand.
You should also check the reviews and ratings of the generator online or offline, and see what other customers have to say about it.
Local Regulations and Permit Requirements
The eighth factor is the local regulations and permit requirements of the generator that you want to use to run your air conditioner.
Generators might be subject to some rules and restrictions in your area, such as noise limits, emission standards, safety codes, zoning laws, or homeowner association policies.
You should check with your local authorities or utility company before buying or installing a generator, and make sure that you comply with all the regulations and requirements.
Maintenance and Upkeep
The ninth factor is the maintenance and upkeep of the generator that you want to use to run your air conditioner.
Generators need regular care and attention to keep them in good shape and performance.
You should follow the manufacturer’s instructions on how to operate, store, clean, inspect, service, repair, and replace your generator.
You should also keep a record of all the maintenance activities that you do on your generator, such as changing the oil, replacing the filters, checking the spark plugs, testing the battery, etc.
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FAQs About The Right Size Generator To Run A Central Air Conditioner
What fuel type works best for central AC generator needs?
Natural gas or propane provides continuous runtime ability. But gasoline standby units are more affordable.
How often should I test and maintain the generator for AC?
Test the generator monthly and service it at least annually or every 200 run hours to keep it ready for emergency central AC power.
Should I hire an electrician to install the generator?
Yes, A Certified Electrician Is Required To Safely Connect The Generator To Your Home Wiring Via A Transfer Switch.
How can I reduce generator noise with the AC running?
Utilize A Protective Outdoor Housing Enclosure And Vibration Dampening Mounts To Minimize Sound.
The Bottom Lines
Mastering the right generator size ensures your central air conditioner runs smoothly. With our guide, you’ve gained the knowledge to make informed decisions.
Remember, considering wattage and adding a safety buffer is vital. Now, confidently keep your home cool, knowing your generator’s got you covered.
Stay chill and power on!
