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:
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Resulting in overly dry indoor air.
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Increasing electricity consumption.
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Accelerating equipment aging.
Conversely, if the air conditioner is too big, it will run short cycles frequently to maintain the set temperature, which may:
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Resulting in rooms being too hot or too cold consistently and reducing comfort.
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Leading to too short operating times to reduce indoor humidity levels.
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Increasing power consumption due to frequent short cycling.
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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.
How to Size Your Mini Split System?
When sizing a mini-split system, it's important to know the cooling and heating requirements of your space. This helps prevent energy waste and ensures effective temperature control. Della will help you step by step with steps to calculate the right BTU, a sizing chart, and a space-specific guideline for your reference.
How to Calculate Mini Split-Size?
Calculating the correct size for a mini-split air conditioner mainly involves 2 steps.
Measure Your Room Area
You don't need to be too detailed since each room's layout is different. Just estimate and add up the areas of the spaces where you want air conditioning.
Calculate BTU
As a basic guideline, you can use approximately 20 BTUs per square foot of living space. For example, a 300 sq ft room typically needs about 6,000 BTUs.
Mini Split AC BTU Sizing Chart
After calculating, if you are still unsure about your results, Della offers you the BTU sizing table to reference, which is based on years of service experience.
| 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 |
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.
Bedrooms
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.
Kitchens
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.
Basements
These spaces can vary widely in size, but for a typical area of 500-700 square feet, you might consider 12,000 to 18,000 BTUs, depending on the level of insulation and humidity.
Home Offices
For a smaller home office, around 100-150 square feet, a mini-split with about 5,000 BTUs would suffice.
Bathrooms
Generally small, a bathroom might only need around 2,000 to 4,000 BTUs, depending on its size and humidity levels.
Covered Patios and Sunrooms
You can consider these areas similar to living rooms if they are enclosed and insulated. That is, for about 300-400 square feet, you might need around 9,000 to 12,000 BTUs.
Garages
If the garage is used as a workshop or commonly occupied space and measures around 400-500 square feet, it could require a mini split air condition of around 9,000 to 12,000 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%.
Sunlight
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%.
Climate
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.
Occupancy
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!
