How To Tell If Your Air Conditioner Is Too Big For Your Home

When it comes to bank account balances and diamond rings, bigger is always better. However, the same can't be said for your air conditioner. An oversized a/c unit may cool your home faster, but it can cause a host of other problems. Here's how to tell if your air conditioner is too big for your house and what you can do to fix the problem.

Why an Oversized Air Conditioner is a Bad Idea

The top reason why an oversized air conditioner is a problem is because the system won't properly reduce the humidity in your home. When untreated air passes over the cooling coils in the a/c unit, some of the moisture it contains is extracted and the dryer, cooler air is sent back into the home. Only a small amount of water is taken out at a time, though. So to properly dehumidify the space, the air conditioner must run for a long enough period of time.

An oversized air conditioner, however, cools the air too quickly and shuts off long before the humidity can be reduced to an acceptable level. In addition to making you feel uncomfortably moist, the high humidity can make it easier for mold to grow in the home.

Another problem with oversized air conditioners is they can actually wear out faster. Air conditioners turn on when the temperature in the home rise above the thermostat setting and turn off once the home has been cooled below the set point. Because an oversized air conditioner cools the home much faster, it will turn on and off more often than is normal for this type of appliance. This can result in a shorter lifespan and more money spent in repairs.

Additionally, the frequent turning on and shutting down results in wasted energy because the air conditioner will spend a few minutes cooling itself down each time it turns on before it starts treating the air. This effort is wasted each time the unit turns off shortly after turning on.

Symptoms of Oversized System

If you live in an area where there is a lot of moisture in the air, then the most obvious sign your air conditioner is too big is it will fail to dehumidify your home. The space will be cool but muggy and clammy. However, this is not a problem for people who live in dry areas.

Another symptom is the appliance will turn on and off more than normal. Generally, the air conditioner should only run about 2 to 3 cycles per hour for about 10 to 15 minutes each time. This may vary a little depending on the outside temperature and how low you have your thermostat set. If your system is running a lot more often or for much shorter periods of time, then it may be too big for the space.

You can also determine if your system is oversized by calculating how many BTUs are required to cool your home. You can do this by multiplying the square footage of your home by 25 BTUs. For example, a 2,000 square foot home would need a system with a minimum BTU output of 50,000. If your unit's output is significantly higher than your calculation, then it may be too big for your home.


The ideal solution is to replace the unit altogether. If you're in the market for a new air conditioner, then work with a knowledgeable HVAC technician to get a system that's the right size for your home.

If replacement is not an option for you, then the alternative is to mitigate the effects of the system. For instance, purchase a separate dehumidifier to reduce the moisture content in the air. Set the thermostat as high as is comfortable to minimize the number of times the unit cycles.

For more tips on dealing with an oversized air conditioning unit or to get a broken unit repaired, contact an HVAC contractor like Perry Heating Cooling in your area.