Why Is It So Hot Upstairs? Tips for Keeping Your Upstairs As Cool As Your Downstairs
During the summer months, the upstairs of a two-story home is often significantly warmer than the downstairs, even when the air conditioning is running. This is a common complaint from homeowners with forced-air HVAC systems with a single thermostat located on the first floor. To understand why the system isn’t keeping the upstairs as cool as the downstairs, it helps to have a basic understanding of how a forced-air system works. Then you can apply a few DIY strategies that will help distribute the cool air more evenly throughout your home.
How Does a Forced-Air HVAC System Work?
A forced-air HVAC system begins at the thermostat. You set the thermostat to your desired cooling temperature, and when the temperature in the room rises above the setpoint, the AC unit kicks on to cool things down. Whenever your AC unit is running, it is drawing air in through return vents, cooling the air, and then forcing the air back out through the supply ducts and into the living space. When the temperature in the living space drops to the setpoint, the thermostat responds by shutting the AC down. Cooler air settles into the lower areas of the house (usually where the thermostat is located); while heat from the outside begins to warm things up again. Because heat rises, the temperature on the second floor rises first, causing the second floor to feel warmer than the first floor. This cycle of cooling down and heating up is one of the main reasons homes with forced-air heat never truly enjoy a consistent temperature, but there are some things you can do to minimize the upstairs/downstairs difference.
What Can You Do to More Consistently Cool Your Home?
Homeowners can perform a number of do-it-yourself adjustments to more evenly cool their homes and make them more energy efficient. Here’s a list of simple modifications you can do on your own, but if you’re not that handy or you just don’t feel comfortable, contact your local HVAC service provider. A qualified technician can easily show you how.
Adjust the dampers. If your vents have levers or dials, that means you can control the airflow by adjusting the dampers (the little louvers inside that move up and down to restrict or open airflow). If the second floor of your home is warmer in the summer months, keep the dampers on the second-floor vents fully open and only partially open the vents on the first floor to force more of the cool air to enter the second-floor areas. (Hint: If your downstairs is colder than your upstairs during the winter, restrict the airflow on the second floor and fully open the vents on the first floor to force more warm air downstairs. See: Why Is It So Cold Downstairs?)
Open top return vents. If you have a top/bottom return vent setup, open the top vents in the summer months. Opening the top vents will make your system draw in air from a higher point in the room where the warmer air collects. (Hint: In the winter months, close the top vents keep the warmer air in the room. See: Why Is It So Cold Downstairs?)
Use your ceiling fans effectively. If you have ceiling fans in your home, you can use them to directly cool a room as well as to improve the overall efficiency of your HVAC system. During the summer months, set the switch on the base of your ceiling fan so that the fan blades move in a counterclockwise direction. When the fan’s blades turn counterclockwise, they push the air in the room downward to create a cooling sensation on your skin even though the temperature of the room doesn’t change. Creating this effect makes it possible to set your thermostat a little higher but make it feel just as comfortable as if the temperature were set lower. See: Which Direction Should a Ceiling Fan Turn?
Pull your blinds and close your curtains during the day, especially on the second floor. Blocking the direct rays of the sun from entering your home during the day will naturally help keep the indoor temperature cooler and place less demand on your AC system.
If you’ve performed all of these adjustments and you’re still uncomfortable, your cooling system may be the wrong size for your home. If your system is too small, it will run longer and more often. If its’ too large, it will operate on shorter, more frequent cycles and potentially burn out the motor. Both of these sizing issues can result in higher energy bills and increased repairs due to mechanical wear and tear. If think your system is the wrong size, call a trusted HVAC contractor for an assessment. You should also have your system serviced annually for peak efficiency and peace of mind.