What size of mini split air condition do I need?

What Size of Mini Split Air Conditioner Do I Need?

Choosing the wrong AC size can ruin summer comfort. Consider mini split AC the size carefully following Della's practical guidance. Check it out!

Imagine spending a scorching summer day in a cool and comfortable room, all thanks to the mini-split air conditioner you bought. But split ACs are not quick consumables; you need to consider some important factors before making a decision, which of them is size. But how do you determine the right size? Don't worry, Della will help you solve any problems you might encounter on the way to achieve bliss without wasting money or energy.

How to Know the Cooling or Heating Capacity for Mini-Split Air Conditioners?

What is the Meaning of BTU in the AC system?

In the AC system, we use BTUs (British Thermal Units) to describe the size of an AC system. BTU is commonly used to indicate the cooling or heating capacity of an air conditioner, that is the size of an AC. One BTU is defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. Therefore, a higher BTU rating indicates that the air conditioner has greater cooling or heating capacity.

Why is BTU important?

Intuitively, people might assume that a higher BTU is always better for an air conditioner. However, this is not the case. Different rooms require different BTUs of air conditioners. If an air conditioner is sized too large or too small, it can lead to various issues:
If you have an AC that is too small, the air conditioner will need to run at high loads for long periods, which may:
  • Resulting in overly dry indoor air.
  • Increasing electricity consumption.
  • Accelerating equipment aging.
Conversely, if the air conditioner is too big, it will run short cycles frequently to maintain the set temperature, which may:
  • Resulting in rooms being too hot or too cold consistently and reducing comfort.
  • Leading to too short operating times to reduce indoor humidity levels.
  • Increasing power consumption due to frequent short cycling.
  • Accelerating equipment aging.
Therefore, the right size of an air conditioner is crucial. Except for impacting efficiency and lifespan, the wrong size of mini split AC affects your living experience and operating costs significantly.
 Room Size (Square Feet) BTU Capacity
 100 to 250 sq ft 6,000 BTUs
 250 to 300 sq ft 7,000 BTUs
 300 to 350 sq ft 8,000 BTUs
 350 to 400 sq ft 9,000 BTUs
 400 to 450 sq ft 10,000 BTUs
 450 to 550 sq ft 12,000 BTUs
 550 to 700 sq ft 14,000 BTUs
 700 to 1000 sq ft 18,000 BTUs
 1000 to 1200 sq ft 21,000 BTUs
 1200 to 1400 sq ft 23,000 BTUs
 1400 to 1500 sq ft 24,000 BTUs
This chart provides the basic BTU capacity of a mini-split system corresponding to room size in square feet. However, adjustments may need to be made based on different room types and other factors.

Adjust your BTUs based on Room Types

The required BTU (British Thermal Units) for a mini-split air conditioning system in different rooms can vary based on the room's size and specific needs. Here are the recommended BTUs for common room types for reference:
Living Rooms and Family Rooms
These areas typically require a larger capacity due to their size and the amount of activity. For a room of about 300-400 square feet, you might need a split air conditioner around 9,000 to 12,000 BTUs. That is, add 1000-4000 BTUs to the calculated BTUs.
Smaller than living areas, bedrooms usually require less cooling capacity. For a standard bedroom of about 150-250 square feet, around 5,000 to 6,000 BTUs would be suitable.
When cooking in the kitchen, the kitchen temperature is often much higher than usual. So for a kitchen of about 300 square feet, consider an AC system with at least 12,000 to 14,000 BTUs.

Other Factors That Affect BTUs

The mini-split calculation steps are a good foundation to start with. However, to select an appropriate size for a mini-split system, except for considering room types, you should also consider these 7 factors. These factors also significantly impact the system's heating and cooling efficiency. Here are the factors and BTUs adjustments based on them for your reference:
Ceiling Height
Standard calculations are based on an 8-foot ceiling. If your ceiling is higher, the air conditioner will need to cool or heat more air. For each additional foot in height, increase the BTUs by about 12.5%.
Rooms with more windows or those facing south get better light, but they also get hotter during the day. If the room gets more sunlight, increase the BTUs by 10%; conversely, if the room gets less sunlight, decrease the BTUs by 10%.
Your geographical location determines the extreme temperatures in your area, which affects the mini-split size needed. For example, if you live in hotter states like Florida or Texas, increase the BTUs by 10% to meet additional demand. However, if you live in colder states like Minnesota or New York, you might need an air conditioner with better heating capacity.
Insulation Quality
Well-insulated rooms retain temperature-controlled air better, reducing the load on the mini-split system. In poorly insulated rooms, increase the BTU capacity to account for greater energy loss.
Crowded spaces can feel stuffier. Therefore, if a room often has more than two occupants, add about 600 BTUs for each additional person.
Other Heat Sources
Besides kitchen appliances, many household electronics also generate heat, such as computers, TVs, and projectors. More electronics mean you might need more BTUs.
Based on these factors above, calculate your base BTU requirement using the room types and then adjust them based on the other factors. This ensures that your mini-split system is neither overworked nor underutilized.
However, you can also consult professional air conditioner manufacturers for help. Della can calculate the most suitable air conditioner size for you based on your home's layout.

In Conclusion

Calculating the right size of mini-split air conditioner for yourself isn't complicated, but you need to take some time to think about it. Doing so can not only improve the efficiency of your air conditioner and save you costs, but more importantly, it can maximize your comfort during the summer!
As a professional HVAC manufacturer, Della aims to create a more comfortable life for every consumer with our new generation of air conditioners. If you are interested in our air conditioners, please feel free to check them out and contact us. We are all ears!


Leave a comment

All comments are moderated before being published.

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.