As an HVAC expert, I have seen many homeowners make the mistake of thinking that a bigger air conditioner is always better. However, this is not necessarily true. When it comes to air conditioning units, size matters. In fact, choosing the right size air conditioner for your home is crucial for optimal comfort and efficiency. First, let's define what we mean by "size" when it comes to air conditioners.
The size of an air conditioner is measured in tons, which refers to the amount of energy it uses to remove heat from your home in one hour. One ton is equivalent to 12,000 BTUh (British Thermal Units per hour). This means that a 5-ton air conditioner has a cooling capacity of 60,000 BTUh. When determining the appropriate size for your home, there are a few factors to consider. The first is the square footage of your home.
Air conditioners are rated in increments of 0.5 tons, with options ranging from 1.5 tons to 5 tons. For example, a 2,000 square foot home would typically require a 3 or 3.5-ton unit, depending on the climate you live in. However, simply dividing the load or capacity by the floor area may not give you an accurate number. For instance, a 3-ton air conditioner in a 3,000 square foot house would result in a load of only 0.001 tons per square foot. To get a more practical number, we can divide the square footage by the tonnage.
In this case, we would get 1,000 square feet per ton. Based on this calculation, only 12% of homes would come close to having an appropriately sized air conditioner using the rule of 400 to 600 square feet per ton. In fact, the average load of 75 homes we studied was about 1,200 square feet per ton. This means that the air conditioning equipment we chose was, on average, 28% larger than the cooling load. So why is it important to choose the right size air conditioner? Well, for starters, an oversized air conditioner can lead to higher energy bills. It will also cycle on and off more frequently, which can cause wear and tear on the unit and shorten its lifespan.
On the other hand, an undersized air conditioner will struggle to cool your home efficiently, resulting in discomfort and potentially higher energy bills as well. Designing an HVAC system starts with choosing the right size air conditioner. It's essential to look at the number of square feet per ton to determine if you're in the right ballpark. For newer homes, this number should be less than 1,000 square feet per ton. If it's higher, it could mean that either the calculation is incorrect or your home is not as energy-efficient as it should be. As an example, I recently installed a 1-ton Midea modulating agitator (essentially a mini-split in a can) in my 1920s vintage house that is approximately 2,400 square feet.
With all interior doors open, this unit covers 100% of my cooling load at an average indoor temperature in the mid-70s F. This translates to a ratio of one ton per 2,400 square feet under design conditions. Without this window unit turned on, my central air with 5-ton ducts only has a duty cycle of about 50%, even when outdoor temperatures reach 90°F. This indicates a load ratio of one ton per 1,000 square feet at outdoor temperatures that are 10°F or more above the 1% design temperature. Understanding how the size of an air conditioner can affect the comfort of your home is crucial. That's why it's essential to rely on reliable advice from an American Standard customer service dealer when making this important decision.
They can take into account various variables, such as insulation, type and number of windows, number of floors, and type of construction, to determine the appropriate size for your home. In conclusion, when it comes to air conditioners, bigger is not always better. Choosing the right size air conditioner for your home is crucial for optimal comfort and efficiency. Don't make the mistake of assuming that a bigger unit will automatically cool down your home better. Instead, consult with an HVAC expert to ensure that you have the right size air conditioner for your specific needs.