Due to the way air conditioners work, it’s not uncommon for them to produce moisture through condensation. Yet major water leaks indicate a serious problem, like clogged drainage or incorrect installation.
So what causes air conditioner vents to sweat? Is it normal for small beads of water to form on supply vents or not?
Georgia Air Cooling & Heating is a top HVAC company in Richmond Hill, GA. Our expert HVAC technicians know how confusing it can be to see water in unexpected places, especially when they connect to an air conditioning unit. Here, we explain the two most common factors leading to AC vent condensation and what you can do about them.
Condensation: A Brief Explanation
Condensation is the moisture that forms when water vapor in warm air interacts with a cold surface. Imagine drinking a cold soda from a can; the longer the cold can sits out in the open, the more droplets will form around its exterior.
The same thing can happen with an air conditioner supply vent. The water that occasionally forms on supply vents is condensate. The water signifies at least one of two things: that the supply vent is extremely cold or the air around the vent has high humidity or moisture content.
Why Condensation on Air Conditioner Vents Is Bad
Seeing condensation on air conditioner supply vents doesn’t necessarily mean the property has a faulty air conditioner. Still, the extra moisture can be a problem if you don’t remedy the situation quickly.
If you ignore the droplets on the vents, the water can eventually leak onto the walls and flooring. The moisture can damage drywall, contribute to wood rot, and cause premature corrosion and rusting of vent covers and air ducts. The water can also make it easier for mold, algae, and bacteria to grow in your home, which can pose a threat to your health with prolonged exposure.
What Causes Condensation on Air Conditioner Vents
A common misconception about why AC vents sweat is that the unit has a refrigerant leak. While a refrigerant leak could result in a water leak, the water that comes from the cooling unit stems from melting frozen coils, not condensation. The problem is also noticeable around the primary equipment instead of the supply vents.
Overly humid air and low supply vent temperature are the two air conditioner vent sweating reasons. The condensation is the result of the cold surface of the air vent being lower than the dew point of the water vapor hanging around the air near the vent.
Reducing your home’s humidity level is the simplest way to address condensation around your air conditioner supply vents. Raising the vent temperature is another option. Pinpointing the exact cause of your moisture problem will help you know which step to take.
Calculating Dew Point and Relative Humidity
When exploring what causes air conditioners to sweat, you should know how your property’s relative humidity and dew point contribute to the problem. A dew point refers to the temperature at which air must be for water vapor to condense and form dew, droplets, or frost if the temperature is below freezing.
According to the Air Conditioning Contractors of America, a 55-degree dew point is the perfect balance between temperature and relative humidity. Consider this breakdown of temperature and humidity levels when the dew point is around 55 degrees consistently:
- A temperature of 80 degrees corresponds to a relative humidity of 42
- A temperature of 78 degrees corresponds to a relative humidity of 45
- A temperature of 75 degrees corresponds to a relative humidity of 50
- A temperature of 72 degrees corresponds to a relative humidity of 55
- A temperature of 68 degrees corresponds to a relative humidity of 63
The lower you set your thermostat to cool your house, the more moisture vapor your indoor air can contain while maintaining a 55-degree dew point. On the other hand, a warmer residence will need a lower relative humidity level to prevent the dew point from rising above 55 degrees, which will make the formation of condensation on air conditioner supply vents more likely.
So what factors do you change to avoid condensation on your supply vents? Do you change the temperature or the humidity level?
To determine whether your temperature or indoor humidity level is the culprit behind wet air conditioning vents, you need to measure them. Once you have those figures, you can input them into a reputable online dew point calculator to see how how the numbers correspond with the ideal 55-degree dew point. That will tell you if your humidity is too high or if you need to adjust your air conditioner’s temperatures.
Steps to Reduce Indoor Humidity
Excessive heat and humidity can make being outdoors extremely uncomfortable and, in some cases, potentially dangerous for your health. Your home’s air conditioner will cool your property by absorbing heat and moisture from the indoor air. Still, your indoor humidity level can rise despite running the air conditioner regularly.
The dew point for outside air during the spring and summer months is usually higher than inside air, so when outdoor air seeps indoors, it elevates the water vapor circulating through your home. Below are several ways humidity can infiltrate your house and what you can do to prevent it.
Crawlspaces
During the summer, it’s common for homes with crawlspaces to have air leakage problems that result in high indoor humidity. The moist air from a vented crawlspace will rise into the main living areas of the house. Consider crawlspace encapsulation to create a vapor barrier between the ground of the crawlspace and the rest of the house.
Air Seepage
Most houses lack sufficient insulation and weatherstripping around windows and doors. As a result, the building can experience unexpected air seepage.
If you suspect your home has high humidity due to air seepage, schedule a blower door test to uncover the sources of your primary air leaks. Seal as many gaps, holes, and uninsulated spaces as possible to maintain reasonable indoor humidity levels during the summertime.
Open Windows
Whenever the temperature outside seems comfortable enough, you might justify opening some windows and doors to get fresh air into your residence. This habit usually wouldn’t be a problem, but you must remember to turn off the air conditioner when you do it.
Even if the outside temperature doesn’t feel overly hot, the air could have plenty of water vapor. By opening windows and doors, you’re inviting more moisture into your indoor air.
Your air conditioner will have to work harder to keep humidity levels reasonable. The presence of outside air will also make it harder for the air conditioner to maintain the thermostat’s temperature. If you must open windows to freshen your home, turn off the air conditioner to avoid putting undue stress on it and causing condensation on the supply vents.
Ventilation
It’s sometimes surprising to learn that some habits invite outdoor air inside, resulting in a shift in humidity. For instance, if you turn on the exhaust hood over your stove while cooking, the hood will blow the indoor air outside. However, outside air will also come in while the exhaust hood is running.
The same thing happens when you turn on the exhaust fans in your bathrooms. If you don’t want to minimize your ventilation usage, you should invest in a dehumidifier to keep your indoor water vapor level reasonable.
Dehumidifiers also work well if you have a large aquarium, take hot showers without running your bath exhaust fan, or have an indoor hot tub or steam shower. Those in-house amenities and practices can introduce more moisture into your home’s air.
Why Air Conditioner Supply Vents Are Too Cold
Knowing what causes air conditioner vents to sweat means understanding that sometimes the air conditioning system is the problem. A common issue is leaky air ducts. Part of the ductwork for your air conditioner may detach or have degraded seals, which encourages air seepage.
Sometimes that air seepage can make the ducts overly cool, resulting in condensation on the supply vents. Conversely, warm air from the attic mingling with the chilled air inside the leaky ductwork can also cause moisture to build up on the vents.
Try turning up your thermostat to raise the temperature of your air conditioner’s supply vents. You should also contact an HVAC professional to inspect your ductwork.
Contact Our Professionals for Reliable Solutions for AC Vent Condensation Causes
The same things that lead to frozen coils or water leaks from the unit itself aren’t necessarily what causes air conditioner vents to sweat. Still, if you’re having problems identifying the causes of moisture on AC vents in your home or notice other issues, our professionals at Georgia Air Cooling & Heating can help. As one of Richmond Hill, Georgia’s top HVAC contractors, our trusted and experienced technicians offer outstanding air conditioning repair and installation. Our licensed and insured crew also helps with upgrading AC units for maximum performance and excellent energy efficiency. Call Georgia Air Cooling & Heating at (912) 513-3756 today to schedule an appointment or to explore our special offers.