Issues Caused by an Incorrectly Sized Air Conditioner

Posted: 2023-07-20

In the past, air conditioning used to be a luxury reserved for the privileged few. Nowadays, the majority of homes are equipped with AC units, which have become an integral part of our lives, especially during the summer. However, not all homes have the right-sized air conditioner installed.

At Four Seasons Air Specialists, your trusted HVAC company in Lino Lakes MN, we provide valuable information on the significance of proper AC sizing.


When it comes to home comfort systems, size plays a crucial role, and bigger is not always better. When selecting an air conditioner for your home this summer, it is vital to consult a qualified professional who can determine the appropriate size for your specific needs. They will calculate the necessary cooling capacity required to keep your home comfortable.

Several factors influence the type of AC unit you need, including the materials used in your building, the size and orientation of your house, the number and location of rooms, the type and efficiency of windows and doors, the climate in your region, the ceiling height, and more.

Let's explore the reasons why an improperly sized system can pose significant problems.

Excessive Power

If your air conditioner is too large for your home, it will have excessive power. An oversized system cools the space too quickly, causing the thermostat to shut down the system before it completes its full cycle and adequately cools your home. In the HVAC industry, this is referred to as "short cycling."

Air conditioners are designed to produce a specific amount of cooled air over a certain time period. However, when short cycling occurs, the system's efficiency is compromised, leading to premature wear and tear. An oversized AC unit is more likely to experience decreased efficiency and have a higher risk of breaking down prematurely compared to a properly sized system.

High Utility and Repair Costs

Oversized air conditioners are significantly less efficient compared to properly sized units. They frequently cycle on and off throughout the day, consuming more energy than necessary. This results in higher utility bills and increased expenses for repairs and system maintenance.

Similarly, an undersized air conditioner can also lead to elevated energy costs. The unit has to work harder to cool your home, resulting in excessive electricity usage. During the peak of summer, an undersized AC may even shut down the entire system due to motor overheating or frozen coils. Even with a programmable thermostat set to your desired temperature, an undersized unit may struggle to provide the level of comfort you desire.

Unsatisfactory Comfort

An air conditioner has two essential functions: cooling the air in your home and removing excess moisture. To eliminate moisture, the air must pass over the evaporator coils, which can lower the temperature by as much as 20 degrees Fahrenheit. When the coil's temperature drops below the air's saturation point, water vapor condenses on the coil's surface.

In the case of an oversized system, it fails to adequately dehumidify the air passing over the cooling coils, resulting in excessive humidity in your home. This creates a breeding ground for mold and mildew. Excessive humidity combined with high temperatures can also pose health risks, particularly for individuals with preexisting heart conditions, potentially leading to heatstroke.

Unfortunately, with an oversized system, the AC cools the room too quickly. As a result, it runs for shorter periods compared to a properly sized unit. Consequently, water cannot adequately condense on the coil and is redistributed into the room, leading to a sticky and uncomfortable feeling.

Hot and Cold Spots

Many homeowners opt for smaller air conditioners due to their lower price. However, choosing a cheaper unit does not always result in savings. If your air conditioner is too small for your home, it will struggle to maintain a consistent temperature, resulting in uneven cooling. Certain rooms may be cooler than others, potentially necessitating the purchase of an additional cooling system.

Consult the AC Experts

For guidance in selecting the right system for your home, reach out to Four Seasons Air Specialists, your reliable Centerville heating and air conditioning contractor.