Purchasing a new air conditioner for your home can be a difficult task. Although there are several practical considerations to keep in mind, nothing beats the importance of selecting the best size AC to cool your space. You don’t want to rush into a decision because it is a substantial investment. Even a rough estimate of the AC size may jeopardize the unit’s efficiency and cooling capacity.

Many people believe that all air conditioners are the same. After all, they work on the same principles and provide cooling. That, however, is not the case. The right size of an air conditioner is determined by various factors, including insulation, room size, number of windows, ceiling height, and others.

There are many reasons for air conditioner cost increases, including increasing the number of users. Although overuse contributes to rising energy bills, the main culprits are insufficient insulation and improperly sized air conditioners.

By carefully selecting the best air conditioner for the type of space it’s intended for, you could save yourself the heartache of a high-power bill.

When deciding on the size of your air conditioning unit, there are four major factors to consider:

We will discuss each factor in greater detail below.

How do the Dimensions Of The Room affect your choice of air conditioning unit

Each room in your house will require a different air conditioning capacity. In general, 0.12 to 0.15 kilowatts of power are needed per square meter of floor area. It is calculated by multiplying the length of a room in meters by its width. We must also consider ceiling heights, as rooms with enough height will always require more energy to cool.

How big of an air conditioner do I need for each room?

We match the appropriate air conditioner for the size of the room in your home here:

Room sizeRoom exampleAir-con kilowatt capacity
10-25 meter squareA small kitchen, study, lounge, small office, bedroom2.5kw
​25-35 meter squareBedroom, small lounge, small room with a high ceiling, office, mid-size kitchen3.5 kW
35-60 meter squareMid-size lounge, large bedroom, bedroom ensuite5-6 kW
60-80 meter squareOffice, large open plan area, small shop, large lounge7-8 kW


Insulation is a material installed within your home’s walls and ceilings to slow or prevent heat flow. Insulation makes your home thermally efficient by keeping heat inside in the winter or increasing the heating capacity outside in the summer. The R-value of any insulation product shows its performance (how well it resists heat flow).

When deciding on the size of your air conditioner, consider the level of insulation in your home. If your home is poorly insulated (has a low R-value), your air conditioner will have to work much harder to keep the place cool or warm. The most common types of insulation used today are reflective insulation and bulk insulation.


Your home’s geographical location will influence your cooling and air conditioning capacity requirements. Suppose you live in a subtropical climate zone with hot and humid summers, such as Africa. In that case, you’ll probably need a more powerful air conditioner than someone who lives in a temperate climate zone (i.e., Melbourne, The United Kingdom, etc.).


When deciding on the right AC unit size, consider the alignment of your home and the size and orientation of windows and glass doors in each room. Do you know which rooms get the midday sun? Generally, southern-facing rooms will be cooler, so they will not require as much cooling capacity as north-facing rooms, which receive the most sun during the day. Your climate zone will also influence the best orientation for your home.

Why Does Air Con Size Matter?

A properly sized air conditioner for your home will operate much more efficiently. When your system is too large or small, you may experience an unpleasant indoor climate and higher energy costs.

Small AC

Buying an air conditioner too small for your home means the unit is constantly running, and the indoor temperature is rarely cool enough. It’s also possible that you’ll notice uneven cooling throughout your house.

Large AC.

Buying an air conditioner that is too big for your house can cause it to cycle on and off all the time. The unit will turn on, rapidly reduce the indoor temperature, and then turn off. Repeating that cycle several times throughout the day causes premature wear and tear on your air conditioner.

How to Calculate the Required Air Conditioner Size

Some online calculators can help you figure out how much cooling or heating you need for your home. Depending on which calculator you use, the capacity takes a variety of factors into account, including:

Some air conditioner installers also offer online calculators and many typical size options on their websites if you are undecided about measures or just want a quick, reasonable estimate before diving into specifics.

To check out the right air conditioner for you, read on to follow these steps to guide you.

Step 1:Types Of Air Conditioners That Are Best Suited To Your Home

Three main types of air conditioners cool analogously. Your home is most likely equipped with one of the following systems: ductless air conditioning, portable air conditioning, or split-system air conditioning.

The split-system air conditioner is the most common type of Air Con unit. This system consists of an outdoor unit and an inner unit that work in tandem to cool and control the dampness position in your home. You need to mount the outdoor component on an external wall of the room that needs to be cooled. If the internal unit is to be mounted on an interior wall, you must install a pump to remove the condensate from the house. We rarely recommend this because pumps frequently become clogged and fail.

With this type of AC unit, you have a plethora of options. You can select a split-system AC based on your preferred energy-efficiency position, noise position, and budget by working with the right type of AC dealer. Cooling multiple rooms using this air con is more cost-effective.

One open-air unit connects to one or additional inner units in a ductless air conditioner. Because they only designed the internal units to cool one room, these systems are best suited for homes that want or bear different climates in each space. Because each room has its unit mounted on the ceiling, wall, or bottom, you can make one room cooler or warmer than another.

They made a portable air conditioner system up of one open-air unit. The unit contains all necessary mechanical factors, similar to the evaporator, compressor, and condensing coil. The portable system uses your home’s ductwork to cool the functional spaces, t. You can choose from the ensuing options grounded on your requirements and desire for an energy-efficient unit; you can choose from single or two-stage systems

Step 2 Examine The Conditions For The AC Size You Need.

Once you’ve determined which type of air conditioner is innovative for your home, look into the conditions for the style you want. Someone generally rates the energy efficacy and cooling capacity of air conditioners. It’s a good idea to be familiar with how those two factors are represented before answering the question, “what size AC unit do I need? “The Seasonal Energy Efficiency Rate ( SEER) of a system indicates its energy efficiency, and cooling capacity is measured in BTUh (British Thermal Units per Hour) or tons.

SEER Conditions

A SEER rating is calculated by dividing a unit’s cooling output by the total energy used over an average cooling season. An advanced SEER rate is attained when lower power is used. Keep in mind that the SEER rate represents a unit’s maximum effectiveness. The most common SEER rating is 14 or 16, but American Standard Heating and Air Conditioning provide units with SEER conditions as high as 22. Most units with advanced SEER conditions have two-stage or variable cooling stages.

What Exactly Is A BTUh Rating?

The BTUh rating describes how important energy your air conditioner or HVAC system uses to remove heat from your home in one hour. Tons (or weight) or BTUh are used to describe the result. A ton of cooling capacity equals BTUh. Weight conditions are assigned to home air conditioners. These conditions are in 0.5-ton supplements, performed on a scale of 1.5, 2,2.5, 3,3.5, 4,4.5, or 5-ton units. For illustration, if you wonder what size air conditioner a square foot home is demanded, you’d presumably go with a 3 or 3.5-ton unit with more stars, depending on your energy output.

Step 3 Calculate The Applicable AC Size For Your Home.

The capacity of your preferred AC unit is only one factor to consider when selecting the correct size AC. Calculate on the trusted advice of a Standard Client Care dealer to get the most out of your AC investment. To ensure that you choose the correct size AC, consider the following features:

Step 4: Request For An Energy Inspection As Well As A Manual J Computation.

You should also consider having a Manual J computation performed as part of an energy inspection. Numerous utility companies give these checkups and reports for free, but if not, an AC dealer or energy adjudicator can be hired to complete the examination. The Manual J computation considers numerous home and environmental characteristics listed above, furnishing you with a highly accurate estimate of the AC size you bear for your room.

Step 5: Match Your Home To The Chart

While consulting with a professionally trained dealer is the stylish way to determine the correct size AC for your room, the chart above can give you an idea based on the size of your home.

Choosing the stylish purchasing and installation company will help you get the most out of the modern AC for your room. The best advice we can give is to go for inverter units that reduce power outputs for smaller spaces.

If you’ve chosen your air conditioner, get in touch and we are more than happy to install it for you!

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