Whether you are buying an AC for the first time or are thinking of replacing the old unit, the first thing you may look for in the air conditioner is tonnage. People usually find it difficult to determine the AC tonnage and the only option they have is to believe in the salesman.

Also, you may like to get a unit with the same AC tonnage as your existing unit. In this case, you should know how to read the tonnage of an AC unit.

This complete guide will make this tricky process easy for you so that you can determine AC tonnage from the model number and make much better decisions.

**What is AC tonnage**

BTU (British Thermal Units) is the term used to measure the heating and cooling capacities of an air conditioner. A single Btu is equal to the heat produced by one birthday cake candle.

Why ac capacity in ton? Tonnage can help you determine the cooling capacity of an air conditioner.

One ton means that the air conditioner can transfer heat at a rate that can cool down a ton of water in 24 hours. 12000 Btu/hr is considered as an air conditioner of one ton. It also means that a one-ton air conditioner can take out the heat produced by 12000 birthday candles in an hour.

**What is AC tonnage per square foot**

AC tonnage per square foot is the term used to measure an area that can be cooled by an air conditioner. This is necessary to calculate before making a decision.

You should measure the area that needs to be cooled and then determine the AC tonnage that will be capable of doing this. It is clear that the bigger an area will be, the higher AC tonnage will be required.

Below is a detailed table of AC tonnage and their capacity per square foot to help you out.

Area Square Feet | BTU | AC Tonnage |

600 sq ft | 12,000 BTU | 1 Ton |

900 sq ft | 18,000 BTU | 1.5 Tons |

1,200 sq ft | 24,000 BTU | 2 Tons |

1,500 sq ft | 30,000 BTU | 2.5 Tons |

1,800 sq ft | 36,000 BTU | 3 Tons |

2,100 sq ft | 42,000 BTU | 3.5 Tons |

2,400 sq ft | 48,000 BTU | 4 Tons |

2,700 sq ft | 54,000 BTU | 4.5 Tons |

3,000 sq ft | 60,000 BTU | 5 Tons |

3,300 sq ft | 66,000 BTU | 5.5 Tons |

3,600 sq ft | 72,000 BTU | 6 Tons |

As a thumb rule, you need about 0.0016 tons of air conditioner or 20 BTU of cooling per square foot. So, if you are going to buy an air conditioner for about 1000 sq foot place, you would need an air conditioner of:

**AC Capacity = 1200 sq ft * 0.0016 tons/sq ft = 2 Tons**

**How AC tonnage is calculated**

You can get a general idea by the fact that you will need 1 tonnage air conditioner for 600 sq ft place. This is a general estimation but some formulas can help you to calculate the exact AC tonnage.

The first way to calculate tonnage is to just multiply the number of square feet of your room by 0.0016. This will give you AC tonnage value in no time. Suppose you are going to buy an air conditioner for 600 sq ft area, you can calculate AC tonnage by:

**AC Tonnage = (Area of Room in Square Feets) * 0.0016 tons/sq ft**

**AC Tonnage = 600 * 0.0016 = 1 Ton**

You can also calculate AC tonnage in terms of British Thermal Units or BTU. Experts claim that you need about 20 BTU of capacity for one square feet area. So you can calculate tonnage for 600 sq ft area by:

**AC Tonnage = (Area of Room in Square Feets) * 20 BTU**

**AC Tonnage = 600 * 20 BTU**

**AC Tonnage = 12,000 BTU**

Now as you have AC tonnage in BTU, simply divide the final value with 12,000 as it is the number of BTU in a one-ton air conditioner, such as:

**AC Tonnage = 12,000/12,000**

**AC Tonnage = 1 Ton**

**What tonnage of AC do I need**

The answer to this question can easily be taken by calculating the square foot area of the room and then deciding the best suitable AC for that area. While the area corresponding to the AC tonnage has been mentioned above in the table, you can do a general estimation by calculating the area first and then multiplying the value with 20. This will give you the exact BTU necessary for the room and diving it with 12,000 will give you the final value as AC tonnage.

**How to calculate AC tonnage for a room**

Although all the methods and ways to calculate AC tonnage for a room have been briefly described, you can get it done with a simple method as well. The method also starts with taking the area and then moving forward.

Suppose that you need to calculate AC tonnage for a room of 20 (length) by 10 (width) feet. Simply multiply them to get the area in square feet as:

**Area = L * W**

**Area = 20 * 10**

**Area = 200**

Now take the square root of the area while diving with 10.

**Square Root = Area/10 SqRt**

**Square Root = 200/10 SqRt**

**Square Root = 1.41**

This calculation suggests that an air conditioner of 1.5 tons would be the best choice for your 10*20 feet room.

**Is 1 ton AC sufficient for 150 sq ft**

1 ton AC is probably the best option for a room of about 100 to 600 sq ft. Some external factors can affect the efficiency but if the room is just 150 sq ft, 1 ton will be more than sufficient in almost all weather conditions. You may need to add 5 BTU per square feel if the room is under extreme sun heat or vice versa. The normal value is 20 BTU per square foot.

**How many kilowatts does a 3 ton ac unit use**

In normal conditions, a 3-ton air conditioner unit uses from 3000 to 3500 watts per hour. Some ACs may use less or a bit high watts depending on the brand or varying weather conditions. The normal range of AC tonnage and their kilowatts usage of energy is as:

AC Tonnage | KiloWatts Per Hours |

1 Ton Air Conditioner | 1,000 Watts |

1.5 Tons Air Conditioner | 1,500 Watts |

2 Tons Air Conditioner | 2,000 Watts |

2.5 Tons Air Conditioner | 2,500 Watts |

3 Tons Air Conditioner | 3,000 Watts |

**Thumb rule for AC tonnage calculation**

The thumb rule of AC tonnage calculation is just to take the area by L * W * H of the room and then divide the value by 1,000. This will directly give you the required tonnage for the room. Suppose you have a room of 10 * 10 * 10:

**AC Tonnage = 1000/1000**

**AC Tonnage = 1 Ton**

**How to find the tonnage of an AC unit**

You can find the tonnage of an air conditioner unit just by looking at the AC unit as there is a combination of digits usually known as the model numbers. This model number looks like a single value but has various kinds of information engraved in it.

While looking for a model number, look at the data plate that has various kinds of information regarding the unit. It is found on the sides of the air conditioner’s outdoor unit. The model number will be a combination of both letters and numerical in a single line.

Look for an even number in the value as AC tonnage is mentioned from 18 to 60 range in model numbers. When you get your number from the air conditioner, simply divide the number by 12 as there are 12,000 BTU in the one-ton air conditioner. This will give you exact AC tonnage without any hard-to-do math.

Even Number in AC Model Number | AC Tonnage |

18 | 1.5 Tons |

24 | 2 Tons |

30 | 2.5 Tons |

36 | 3 Tons |

42 | 3.5 Tons |

48 | 4 Tons |

60 | 4.5 Tons |

The position of even numbers in model numbers varies from model to model or brand to brand. You should know the exact place of tonnage numbers so that you can get the right tonnage instead of getting the wrong assumptions.

**York tonnage by model number**

To determine York tonnage with the help of the model number, you should look for the first two digits of it. These two digits are the representation of AC tonnage. The value can differ in some decimals but it will be quite equal to the exact AC tonnage or BTUs. Suppose your York model number is YHE60B21SA, So, the tonnage of the AC will be as:

**AC Tonnage (Capacity) = First Two Digits of Model Number / 12**

**AC Tonnage = 60/12**

**AC Tonnage = 5 Tons**

**Carrier tonnage by model number**

First of all, you need to decode the model number or simply know the right position of numbers that are representing the AC tonnage. While finding Carrier tonnage by model number, you should probably look for the 7th and 8th position digits in the model number.

The biggest indication of these numbers’ authenticity is that they usually range from 18 to 60 in the model number. Suppose we have a Carrier model number as 38EZB030211, the AC tonnage will be as:

**AC Tonnage (Capacity) = 7th and 8th Digits of Model Number / 12**

**AC Tonnage = 30/12**

**AC Tonnage = 2.5 Tons**

You can get AC tonnage by the general estimation that the digits “30” indicate 30,000 BTU of cooling capacity in your air conditioner. As 12,000 BTU is the cooling capacity of a one-ton unit, dividing 30,000 by 12,000 will directly give you 2.5 as result.

**Trane tonnage by model number**

When it comes to determining Trane Tonnage by model number, you should look for the 5th and 6th digits of the air conditioner’s model number. Do keep this fact in mind that this position includes all digits as well as letters of the air conditioner model numbers. You can get a clear idea by analyzing the Trane model number which is TWF024B140C0. The AC tonnage for this number will be as:

Digit | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |

Model Number | T | W | F | 0 | 2 | 4 | B | 1 | 4 | 0 | C | 0 |

**AC Tonnage (Capacity) = 5th and 6th Digits of Model Number / 12**

**AC Tonnage = 24/12**

**AC Tonnage = 2 Tons**

**Lennox tonnage by model number**

Where all the above-mentioned brands come with a single line model number, the Lennox model number is a cluster of different groups. Each group could be of two to four digits with having “-” in the middle.

For knowing the Lennox using the model number, you should look at the second cluster of the model number. It usually has three digits where the first digit is 0 and the next two digits represent the tonnage. Suppose, if you have a model number XC21-048-222-01. The second cluster having 048 is representing the tonnage which will be given as:

**AC Tonnage (Capacity) = Second Cluster of Digits / 12**

**AC Tonnage = 48/12**

**AC Tonnage = 4 Tons**

**Goodman tonnage by model number**

To know the Goodman tonnage, look for the 7th and 8th position digit or the 4th and 5th position digit from the bottom. The Goodman model number is usually in the form of GSZ140361KF:

Front Position | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 |

Model Number | G | S | Z | 1 | 4 | 0 | 3 | 6 | 1 | K | F |

Bottom Position | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 |

**AC Tonnage (Capacity) = 7th and 8th Position / 12**

**AC Tonnage = 36/12**

**AC Tonnage = 3 Tons**

**Bryant tonnage by model number**

The 8th and 9th position digits in the model number are the number that is representing the Bryant tonnage. This air conditioner model number is usually PA3ZNB042000ABRP. So the tonnage can be taken by:

**AC Tonnage (Capacity) = 8th and 9th Digit / 12**

**AC Tonnage = 42/12**

**AC Tonnage = 3.5 Tons**

**Daikin tonnage by model number**

For Daikin tonnage by the model number, you should look for the first two digits following 3 letters. These numbers will be divisible by 6 or 12 so that you can get the values in BTUs and determine the best suitable air conditioner capacity for your room. For model number, RXS12LVJU, the AC tonnage will be as:

**AC Tonnage (Capacity) = First Two Digits from Right / 12**

**AC Tonnage = 12/12**

**AC Tonnage = 1 Tons**

**Amana tonnage by model number**

The position of AC Amana tonnage varies in old and new air conditioner models. While in old air conditioners, Amana tonnage was written as the first two digits of the model number just after 2 to 3 letters. But in new models in the market, the tonnage is mentioned at 7th and 8th position in the model number. For older models, the number may look like RHS24ADE1, while ASC1304813D is in newer ones.

**American standard tonnage by model number**

Look for the number that’s divisible by the 6 or 12 and has been positioned at 7th and 8th from the front while 8th and 9th from the button. It can be said that American standard tonnage is usually placed almost in the middle of the air conditioner model. The model number for American Standard tonnage is almost like 4TTB3054D1000CA. Here 60 is representing the AC tonnage dividing the value by 12 will give the answer as 4.5 tons.

**AC Tonnage (Capacity) = 7th and 8 digits of Model Number / 12**

**AC Tonnage = 54/12**

**AC Tonnage = 4.5 Tons**

**Heil tonnage by model number**

Finding Heil tonnage by model number is probably the easiest as it is rightly placed in the middle of the model number. Most commonly the digits representing the Heil tonnage are surrounded by letters but the number can only come in minimum cases. In terms of their positions, it can be said that digits are placed at the 5th and 6th positions both from the front and bottom of the model number. The model number could be ACB12AKA1.

**AC Tonnage (Capacity) = 5th and 6th of Model Number / 12**

**AC Tonnage = 12/12**

**AC Tonnage = 1 Tons**

**ICP tonnage by model number**

ICP stands for International Comfort Products and its air conditioner is considered one of the best in the market. The number for tonnage is usually placed just at the 5th and 6th position of the model number but can be moved one place back or forward. In this case, finding the value divisible by 6 or 12 will help you out. ICP model number is in the form, WCH3484CKC101.

**AC Tonnage (Capacity) = 5th and 6th of Model Number / 12**

**AC Tonnage = 48/12**

**AC Tonnage = 4 Tons**

Curious to know how many watts does a 15000 btu air conditioner use or what is the best 12000 btu air conditioner room size?