“Why is my air conditioning working upstairs, but not downstairs?” Did you know that this question is one of the top key phrases that people search for in Google? In fact, if you type that question into Google, you’ll get more than eight million results! Clearly, this particular air conditioner malfunction is quite common. However, here in Arizona, most homeowners actually have the opposite problem. They get a nicely cooled off downstairs, but meanwhile, the upstairs is stiflingly hot. It’s not easy to sleep when it’s too hot upstairs, so this is definitely a problem that you’ll want to call an HVAC technician about.

Why Is My Air Conditioning Working Upstairs, But Not Downstairs: The Short Answer

If you’ve been having problems sleeping during the summer because it’s too hot upstairs, you’re not alone. It happens because of the laws of thermodynamics. Central air conditioners work by blowing chilled air into the home. Since hot air rises, the temperature on the second story of the home will rise. Meanwhile, the downstairs gets nicely chilled.

The thermostat will sense that the ideal temperature downstairs has been reached, and it will shut off the AC. This is why many homes in Arizona are unevenly cooled, with pockets of hot and cold air throughout the house. Of course, this isn’t the only possible reason for uneven cooling in your home. Another common culprit is an improperly sized central air conditioner.

The Role of a Properly Sized System

The comfort of your family and the energy efficiency of your system depend in large part on the proper sizing of the AC. This is one reason why it’s so crucial to choose a highly rated HVAC company with experienced, certified technicians. A certified technician will accurately measure your home and calculate the right size and capacity of air conditioning unit for your family.

It’s often assumed that the larger the AC unit is, the more comfortable the home will be. In fact, an oversized unit can prove disastrous for your family’s comfort—and for your energy bills and the overall lifespan of the system. An oversized system will cause the air to reach the thermostat’s setting too quickly. It will shut off before the entire home gets properly chilled. This is known as short cycling, and it causes significant wear and tear on the unit, as well as uneven cooling.

On the other end of the spectrum, an undersized AC unit is also problematic. It will lack the capacity to evenly cool the home. In addition, it will be forced to run longer than it should, which will inflict more damage from premature wear and tear. This will also lead to a shortened lifespan. In other words, you’ll have to pay to replace the unit earlier than expected.

The Registers and Design of Your Home

Another issue to consider is the design of your home. Do you have rooms with significant Western or Southern exposure? If so, you need more air flow to those rooms. If there is insufficient airflow, there will be uneven pockets of cold and hot air. In Southern Arizona homes, it’s ideal to have larger registers upstairs to increase the volume of air flowing there. This compensates for the hot air rising to the second floor.

The Importance of Sealed Ductwork

Often, problems with a home’s air conditioning aren’t actually caused by the air conditioning unit itself. There is a good chance the problem could be with your ductwork. Many homeowners have leaky ductwork and do not even realize it. When the ductwork isn’t sealed properly, positive pressure is created. This causes the air to flow to areas of the home that aren’t ideal, such as the attic and crawl spaces, rather than the downstairs and upstairs floors. If you have pockets of hot and cold air in your home, it’s definitely a good idea to ask the HVAC technician to evaluate your ductwork for leaks. If any leaks are detected, the technician can use a ductwork sealing product.

The Location of Your Thermostat

Every multi-story home should have multiple thermostats. If you have an older home or a poorly designed home, however, you might only have one thermostat on the ground floor. This can result in uneven cooling. Your HVAC technician may recommend adding another thermostat.

Are you still wondering “Why is my air conditioning working upstairs, but not downstairs?” Call Intelligent Design and request the next available appointment with one of our experienced and certified technicians. We’ll closely inspect your system, evaluate your cold and hot pockets, and figure out exactly what’s causing the problem. Then, we’ll explain our recommended solutions so you and your family can comfortably enjoy every part of your home. You can reach our friendly office staff in Tucson by calling (520) 462-1538.

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