Air Conditioning Is Working Downstairs But Not Upstairs (11 tips)

You flip the switch and hear the satisfying hum of your air conditioner coming to life. You walk over to the thermostat to set it at your perfect temperature and head out for the day. But when you get upstairs, the cool air is nowhere to be found. What’s going on?

What to do if your air conditioning is working downstairs but not upstairs

One of the most common air conditioning problems is that the unit is not cooling the entire house evenly. A number of factors can cause this, but the most likely culprit is that the upstairs unit is not receiving enough airflow. If this is the case, there are a few things you can do to try to improve airflow and get your upstairs unit cooling properly again.

1. Single Air Conditioning System or Thermostat

If your home doesn’t have a new air conditioner, there’s a chance that it functions with just one cooling system and thermostat. However, if this is the case, be aware that single thermostats can often leave warm spots in other areas of your house because they only sense temperature for one area.

If your thermostat is on the first floor, it will only turn on the air conditioning when that area becomes warm. However, since temperature varies throughout the house, this setting often results in a hot upstairs and a cool downstairs.

Here’s how to fix it:

If you have a single air conditioning/heating unit, the ductwork may be converted and an additional thermostat installed.

You can do it by yourself if you know how or you can consult with an HVAC specialist.

2. The HVAC Unit Is on the First Floor

Air conditioners must both remove hot air and introduce cold air to the second floor. Because central HVAC units are situated on the first floor, this adds another level of complexity since cool air may continue to sink to the first floor. As a result, your HVAC unit must constantly push cold air up into the home. This can quickly overload your air conditioning unit, causing it to wear down fast.

Here’s how to fix it:

Make sure your ductwork is not leaking and that all the vents in your home are open. This will help ensure that cold air actually reaches the second floor. Is your AC properly sized for your home? An HVAC professional can help you determine if your unit is too small or needs to be replaced.

3. The hot roof can also impede the cooling process

This is a problem that is more common in homes with flat roofs. In the summer, the sun can heat up your roof, making it quite hot. This hot air will enter your home through the attic and cause the upstairs to be warmer than the downstairs.

Here’s how to fix it:

Make sure that your attic is properly insulated and ventilated.

Consider adding more insulation to your attic to help keep heat from seeping in and make your air conditioner work harder than necessary.

4. Faulty or Inadequate Ducts

If you have an old central heating and cooling system, it might be using outdated and inefficient ducts. The ducts might have leaks or be installed improperly in the first place. You might also not have enough ducts reaching the second floor.

Here’s how to fix it:

Consult with an HVAC professional to see if your ductwork needs to be replaced or repaired.

If you don’t have enough ducts reaching the second floor, they can be added.

5. Your HVAC Unit Is Cooling More Rooms Than Its Capacity

It’s possible that your HVAC system can’t keep up with the recent changes in your home. For example, it might only be able to cool a two-story house with four bedrooms. If you’ve added more rooms recently, it may be running at full capacity or beyond.

Here’s how to fix it:

If your HVAC unit is running constantly, it might be time for an upgrade. A new, more powerful unit will be able to cool your home more effectively and evenly.

6. The Temperature on Your Thermostat Is Too High

A common issue for people with more than one story in their home is that the second floor is often too hot. The reason for this is that most people set the same temperature for both floors, without taking into account that hot air rises.

To fix this problem:

Try setting the temperature of your second floor two degrees lower. Smart thermostats and sensors can be a big help when trying to maintain different temperatures in multiple rooms or floors.

7. Increase Airflow to the Second Floor

The HVAC dampers can be adjusted to increase air circulation on the second floor. During the summer, close the dampers for the first-floor vents to force more air through the second-floor vents. If you cannot find the dampers or your HVAC unit does not have them, you can close the registers on the first floor.

8. Clean or Replace Your Air Filters

In the summer, dusty and clogged air filters block airflow and hamper your HVAC unit’s ability to keep the upstairs cool. Cleaning out your air filters on a regular basis and changing them after every three to four months is a must.

9. Instead of “Auto,” keep your HVAC fan on “On.”

If your thermostat’s fan setting is set to “auto,” change it to “on” to address the issue of the AC not cooling upstairs. Turning on the blower fan will provide an equal distribution of air throughout the house. When the fan is turned on “auto,” it only activates when real cooling is taking place. When the fan is turned on “on,” however, even if the cooling cycle has been switched off, the fan circulates air around your home.

10. Upgrade Your HVAC Unit

The average lifespan of an air conditioner is 10-15 years. If your HVAC unit is older than this, it may not be able to properly cool your house. Another frequent problem is that many houses have the wrong size of HVAC equipment installed. To determine whether you need to replace your HVAC unit or if it is too small to cool the second floor of your home, talk with a reputable HVAC specialist.

11. Invest in a Ductless Air Conditioner for your home

If your central air conditioner is struggling to keep your upstairs cool, consider purchasing a ductless unit.

There are many types of ductless air conditioners on the market today – mini-splits, portable units, and window units among them. These ACs offer a self-contained way to cool one room each and have become increasingly popular in recent years.

Ductless air conditioners make it easier to create climate zones and are more cost-efficient since you only use them in the rooms you’re occupying.

Final thoughts

It’s no surprise that many homeowners face air conditioning problems in the summer. Between dusty filters and clogged ducts, there are a number of potential causes for an AC unit not cooling upstairs. While some solutions, like cleaning your air filters, are easy enough to do yourself, others may require more time or money. If you’re struggling to keep your home cool this summer, it might be time to try one of these 11 solutions. Hopefully, one of them will help you achieve the perfect temperature in every room of your house.