Choosing the right size central ac for your home can be challenging if you don’t know what to consider. Yet, you cannot afford to get it wrong. A whole-house air conditioner is an expensive investment that needs prior deliberation.

Luckily, it’s easy to determine what ac size is suitable for your home. If you’re still wondering, “What size central air conditioner do I need?” read on. By the end of this article, you will learn two methods you can use to get a direct answer to your question.

Contents

## The Estimation Method

The estimation method hangs on the HVAC industry rule of **thumb: 20 BTU per square foot.**

The formula is straightforward. You can calculate how many BTUs you need to cool your home by multiplying the area in sq. ft. by 20 BTU.

### How many BTUs Do I need for 2,400 sq feet?

We will use the estimation formula above to calculate how many BTUs you need to cool 2,400 sq. ft. (Area x rule of thumb)

2,400 sq. ft. x 20 BTU = 48,000 BTU

In other words, you need 48,000 BTUs to cool 2,400 sq. ft.

### What Ton size air conditioner do I need for 2,400 sq. ft.?

Air conditioners are available in several tonnage sizes. These include 1.5 ton, 2 ton, 2.5 ton, 3 ton, 3.5 ton, 4 ton, and 5 ton. You can convert BTU to tons if you want to know the capacity of the ac in tons.

The rule in conversion is **one ton equals 12,000 BTU.** Therefore, you need to divide 48,000 BTU by 12,000 BTU to get the capacity in tons.

48,000 BTU ÷ 12,000 BTU = 4 tons.

So, a 4-ton air conditioner will cool 2,400 sq. ft.

## The Accurate Method

The estimation method takes the area of the house into account. However, many other factors impact the cooling load.

A professional contractor using the Manual J process to calculate your home’s cooling load will consider these factors. These include insulation, ceiling height, number of people living in the house, sun exposure, etc.

If you don’t want to hire a contractor, our AC BTU calculator can simplify the Manual J process for you. This is a more accurate way of finding the capacity of the ac unit in very little time-read under a minute.

### What Size AC Unit do I Need for My House? (Calculator)

We will work using the following conditions

- Climate region: Zone 3
- Insulation grade: Good
- Sun exposure: Average
- Number of windows: 5
- Number of doors: 2

According to the calculator, you need a central ac with 43,200 - 51,840 BTUs to cool 2,400 sq. ft.

To get the capacity in tons, you can use the **ac tonnage calculator** (link to AC Tonnage article) instead.

### AC Sizing Chart for 2,400 sq ft House in Different Climate Zones

The following table shows different ac sizes for 2,400 sq. ft. in varying climate regions.

Climate Zones | Recommend Air Conditioner BTU Size | Recommend Air Conditioner Tonnage Size |
---|---|---|

Climate Zone 1 & 2 (hot) | 52,800 - 72,000 btu | 4 - 5 ton |

Climate Zone 3 (warm) | 48,000 - 57,600 btu | 4 - 5 ton |

Climate Zone 4 (moderate) | 43,200 - 52,800 btu | 3.5 - 5 ton |

Climate Zone 5 (cool) | 38,400 - 48,000 btu | 3 - 4 ton |

Climate Zone 6 (cold) | 33,600 - 43,200 btu | 3 - 3.5 ton |

Climate Zone 7 (very cold) | 28,800 - 38,400 btu | 2.5 - 3 ton |

## Final Word

On estimate, you need a central ac with a 48,000 BTU capacity to cool a 2,400 sq. ft. house. But if you want a more accurate answer, use our AC BTU calculator since it considers various factors. All you need to do is fill in the required details in their respective boxes. It will take you less than a minute.