LS Aircon Servicing Singapore

Size of Aircon Unit

What Size of Aircon Unit Do I Need

Choosing the right size of aircon unit for your home is crucial for maintaining comfort and energy efficiency. An aircon unit that’s too small won’t cool your space effectively. At the same time, one that’s too large will consume more energy than necessary, leading to higher utility bills and potential humidity issues. This comprehensive guide will help you understand the factors to consider when selecting the proper size aircon unit for your needs, ensuring you stay relaxed and comfortable.

The Right Size of Aircon Unit for Your Space

Air conditioning has become an essential part of modern living, providing relief from the heat and improving indoor air quality. However, selecting the right size of aircon for home can be a daunting task due to the various factors involved. 

This guide aims to simplify the process by breaking down the key considerations and providing practical advice to help you make an informed decision. Whether installing a new system or replacing an old one, this guide will ensure you choose an aircon unit that perfectly matches your requirements. LS Aircon Servicing Singapore can also assist you with their services, like aircon installationgas top-upaircon chemical wash, etc. 

What Size of Air Conditioner Unit Do I Need?

Aircon units are typically measured in British Thermal Units (BTUs) or tons. The BTU rating indicates the amount of heat an aircon unit can remove from a room per hour. A higher BTU rating means a greater cooling capacity. 

One ton of cooling is equivalent to 12,000 BTUs. The size of the aircon unit you need depends on various factors, including the size of the space, the climate, and the specific characteristics of your home.

What size of AC unit do I need for the home?


1. Room Size

The most critical factor in determining the right size of aircon unit is the size of the room you want to cool. Measure the length and width of the room to calculate its square footage. As a general rule of thumb, you need about 20 BTUs per square foot of living space. For example, a 500-square-foot room would require an aircon unit with a capacity of approximately 10,000 BTUs.

2. Ceiling Height

Standard calculations assume a ceiling height of 8 feet. If your ceilings are higher, you’ll need a unit with a higher BTU rating to cool the space effectively. Add about 10% more BTUs for each additional foot of ceiling height.

Size of Aircon Unit i need

3. Climate and Location

The climate in your area plays a significant role in determining the right size aircon unit. Hotter climates require units with higher BTU ratings to maintain a comfortable indoor temperature. Additionally, consider the room’s location within your home. Rooms with lots of sunlight or on upper floors may require more cooling power.

4. Insulation

Proper insulation helps maintain a consistent indoor temperature and reduces the load on your aircon unit. If your home is well-insulated, you may need a smaller unit. Conversely, poor insulation requires a larger unit to compensate for the heat entering your home.

5. Number of Occupants

The number of people regularly occupying a room affects its cooling requirements. Each person generates body heat, which can increase the temperature. Add 600 BTUs for each person beyond the first two occupants to ensure adequate cooling.

6. Heat-Producing Appliances

Appliances such as ovens, stoves, and computers generate heat, increasing the cooling load on your aircon unit. Consider the presence of these appliances in the room when calculating the size of aircon unit.

Calculating the Right Size

To determine the appropriate size aircon unit for your space, follow these steps:

  1. Please measure the length and width of the room to calculate its square footage.
  2. Multiply the square footage by 20 BTUs (the general rule of thumb).
  3. Adjust for ceiling height by adding 10% for each foot above 8 feet.
  4. Consider the climate and add more BTUs if you live in a hotter area like Singapore.
  5. Add 600 BTUs for each additional person beyond the first two occupants.
  6. Account for heat-producing appliances by adding extra BTUs as needed.

Choosing the Right Type of Aircon Unit

1. Window Air Conditioners

Window aircon is suitable for cooling single rooms. They are easy to install and relatively affordable. When choosing a window unit, ensure it fits the dimensions of your window and has the necessary BTU rating for your room size.

2. Split-System Air Conditioners

Split-system aircon consists of an indoor unit and an outdoor unit. They are ideal for cooling multiple rooms or larger spaces. These units are more efficient and quieter than window units but require professional installation.

Size of Air conditioner Unit

3. Portable Air Conditioners

Portable air conditioners are versatile and can be moved from room to room. They are easy to install and suitable for temporary cooling needs. However, they tend to be less efficient than window or split-system units and require venting through a window or wall.

4. Central Air Conditioning

Central air conditioning is the most comprehensive solution for cooling an entire home. It uses a network of ducts to distribute cool air throughout the house. This system is the most expensive and requires professional installation but provides consistent and efficient cooling for large spaces.


Choosing the right size of aircon unit is essential for maintaining a comfortable indoor environment and optimizing energy efficiency. By considering factors such as room size, ceiling height, climate, insulation, number of occupants, and heat-producing appliances, you can determine the appropriate BTU rating for your needs. Understanding the different types of aircon units and their features will help you make an informed decision that meets your requirements. 

Frequently Asked Questions

When your unit operates for shorter durations, it doesn't filter the air as effectively as an appropriately sized air conditioning unit.
Ensure 2–3 feet of clearance on all sides to maintain sufficient breathing room for your condenser optimally.
A helpful rule of thumb is to allocate approximately 20 BTUs for every square foot of floor area.