Generally, you need a 14,000 BTU air conditioner for a 600 square foot area. This figure applies to standard climatic and room conditions. If you live in a hotter area, you may need a higher-capacity air conditioner. The opposite is true if you live in a cooler climate.
The figure also assumes single occupancy. If the room is likely to host more than one person at any given time, then you need a larger air conditioner to keep everyone feeling cool and comfortable.
The rest of this guide discusses in greater detail factors and considerations to help you find the best size air conditioner for your 600 square-foot room, depending on the unique conditions of your location and the room.
Understanding BTU Capacity Measurements (BTUs)
Air conditioner capacity is measured in British Thermal Units (BTUs). If you’ve shopped for a home heating system before, you’ll also recall that heaters are also measured in BTUs.
The British Thermal Unit (BTU) measures a cooling or heating appliance’s capacity to remove or add heat to a room per hour. It tells us how much heat the appliance can remove from the given area per hour for air conditioners? Therefore, a 10,000 BTU air conditioner can remove 10,000 BTUs worth of heat every hour.
Some air conditioners, especially central units, indicate the heat removal capacity in tons. Just remember that one ton = 12,000 BTUs.
Top Factors that Influence Air Conditioner BTU Sizing
The first primary consideration when shopping for an air conditioner is the size of your room or the application. Generally, it would help if you had a larger air conditioner for a larger space and vice versa.
Most experts recommend 10,000 BTU for applications ranging from 400 to 449 square feet, 12,000 BTU for 450 to 549 square feet, 14,000 BTU for 550 to 699 square feet, and 18,000 BTU for applications 700 to 1,000 square feet.
If you follow the recommendations above alone, you will pick a 14,000 BTU air conditioner for your 600 square-foot application.
Unfortunately, size isn’t the only factor determining how much cooling you need in the home or a specific room. Other critical considerations are as follows;
If you live in a warmer climate, you may need more air conditioning BTUs. The reason is simple – it takes a more powerful air conditioner to remove the excessive heat.
Consider two consumers with similar-size 600 square-foot bedrooms. Both are shopping for air conditioners to address summer heat. However, the first one lives in the generally cool UK climate, where average summer temperatures since 2015 have never exceeded 77˚F. Meanwhile, the second one lives in Dubai, where average summer temperatures hover around 100˚F.
You can quickly tell that the second consumer living in Dubai needs more cooling power to offset the scorching hot temperatures.
The Home’s Insulation Factor
What makes your home extremely hot in the summer is the property of heat to naturally transfer from areas of high concentration to those of low concentration. This is known as heat balance. In the absence of conscious effort to limit entry, the hot air from outside will enter the house, forcing the cool air out until the air inside is as hot as that outside.
You can create barriers through home insulation to limit the entry of warm air and loss of cool air. Indeed, walls and closed windows and doors serve as natural insulators.
However, the quality of insulation varies from one home to the next. The measure of your insulation quality is given as a resistance value (R-Value). Feel free to call an HVAC to help you measure the R-Value of your home.
A higher R-Value means a higher resistance to heat passage into or out of the home. Less heat allowed inside the house means you can do with a lower-capacity AC. The opposite is true. Remember that older homes are naturally less insulated compared to newer properties.
Which Part of the Home?
Not all rooms inside the house are equal. For instance, the bedroom tends to be house fewer people and has fewer airflow obstructions. The result is usually better climatic conditions. Even on the hottest of days, your bedroom will likely be cooler than the rest of the home. Bathrooms are also cooler than the rest of the home.
Meanwhile, the basement and kitchen tend to be some of the hottest parts of the home. For the kitchen, it’s primarily because of the cooking (heat) that goes on throughout the day. It makes it a tad more challenging to keep the temperatures at the desired level.
Basements are mostly warmer than the rest of the home because of the massive foundation walls that slow down temperature changes. Also, the basement has few outlets for heat to exit.
These differences often mean that you need a stronger AC for the basement and kitchen. In the kitchen, for instance, you’re advised to add 4,000 BTUs to the standard recommendation.
This is a factor a lot of consumers miss. The air conditioner’s efficiency determines how many BTUs worth of heat can remove vis-à-vis the amount of energy lost in the process to inefficiencies.
Let’s assume that you go by the standard recommendation and get a 14,000 BTU AC for your 600 square-foot sitting room. So, you come across two Pioneer products – the first a ductless mini-split rated at 90% efficiency and the other a window AC rated 70% efficiency.
Unfortunately, these two appliances won’t cool your home at the same rate. The mini-split can remove an impressive 12,600 BTUs of heat, losing the remaining 1,400 BTUs worth of energy to inefficiencies. Meanwhile, the window AC can only remove 9,800 BTUs of heat. The other 4,200 BTUs worth of energy is lost to heating and other inefficiencies.
Always keep this in mind. The higher the efficiency, the better. However, if you must pick a low-efficiency AC, then you’ll need a higher-capacity unit to compensate for the power lost to inefficiency.
Other Key Considerations
Other important factors to consider when shopping for an air conditioner for your 600 square-foot room include the number of occupants, shading/sunshine, and the ceiling height.
All the recommendations you’ve seen so far assume single-person occupancy. If the room in question regularly houses more than one person, add 600 BTUs for every extra person.
Thus, if it’s a bedroom used by four people, you need to add 600 BTUs for each of the three extra occupants, translating to 1,800 BTUs. Also, adjust the final figure by 10% up or down for sunlight-exposed and shady areas, respectively.
The above recommendations also assume a standard 8-foot ceiling height. For lower or higher ceilings, adjust the calculations as appropriate. For example, add 10% per foot for higher ceilings or remove 10% per foot for lower ceilings.
The Danger of Under or Oversizing an AC
As a final point, be very careful about overdoing air conditioning. Too little or too much cooling can have damaging effects on you and your family’s health, among other consequences.
Consequences of Under-sizing an AC
Undercooling means buying a humidifier too small for your home. It comes with two grave consequences;
- A small AC can’t keep you cool: If you want to stay cool and comfortable throughout the summer, you want the right size AC. Buying a unit recommended for 300 square-foot spaces, such as a 7,000 BTU AC, for your 600 square-foot bedrooms will leave the room feeling hot and sweaty.
- Faster wear and tear: A smaller AC needs to run faster and longer to keep up with the larger area’s cooling demands. The result is often more frequent breakdowns, more repairs, and ultimately a shorter appliance life.
- More noise, less comfort: Finally, when the AC needs to work harder, there’s a greater risk of noise. The fans become louder as the AC struggles to meet the cooling demands. Soon, the fans may get damaged and make even more noise.
Consequences of Oversizing an AC
An air conditioner too big for the 600 square-foot room is just as dangerous. For instance, buying a 25,000 BTU AC, typically recommended for large spaces between 1,000 and 1,200 square feet, can come with the following issues;
- Dry air: When air conditioners remove heat from the room, they also remove the moisture in the air. If it’s an unnecessarily large AC, it can deplete indoor moisture faster than the moisture can be replaced. The result is often dry air conditions that can cause dry skin and lips. Dry conditions also tend to trigger allergic reactions and asthma.
- Frequent on-off cycles: Modern air conditioners self-regulate by automatically going on and off to maintain the temperature on the thermostat. If your AC is too big for the room, it will reach the thermostat setting faster, thus go off more often. Shorter AC cycles can damage the compressor and compromise the AC fan.
So, What Size Air Conditioner is Best for 600 Square Feet?
The short answer is 14,000 BTUs. For the standard 600 square-foot room in an average climate, a 14,000 BTU air conditioner is optimal.
However, the actual value may vary depending on your climatic conditions, the insulation quality of the room, and the efficiency of the AC, among other factors.
For instance, if you live in a typically cool climate, you may not even need cooling in the first place. Meanwhile, those living in temperate climates may need an AC as large as 20,000 BTUs.