As summer approaches and the weather grows warmer, air conditioning usage increases. With the new focus on indoor air quality, you may wonder if and how air conditioning affects IAQ. Let’s address several myths surrounding air conditioners and understand how they actually impact your space’s air quality.
Common Air Conditioning Myths
Air conditioners bring outdoor air inside.
False. Air conditioners recycle air that is already present in your home. The cool air that passes through providing a comfortable temperature while the A/C unit is running is a result of refrigerants, fans and evaporator coils. It is not the result of outdoor air being brought into the home.
Air conditioners purify air or air conditioners filter pollution.
False. Air conditioners cannot and do not purify air. The air filter located near the return air duct or air handler does filter dust, pollen and other allergens. But it’s a misconception that the air filter is a part of the air conditioner itself, rather air filters are a part of the entire HVAC system. Air filters with a higher MERV rating are better able to filter particles and filter finer particles compared to lower MERV ratings. Yes, air filter choice matters–but no, the condensing unit itself does not clean indoor air.
How Do Air Conditioners Actually Work?
Let’s take a look at how an A/C system actually works and what it really does. That is–for a central air conditioning system or whole-home air conditioner.
First, the fans in an air conditioning unit draw warm air in through a vent and blow it over the evaporator coil. The evaporator coil is filled with refrigerant which removes heat from the warm air. The heat is removed in such a way that the refrigerant transforms from liquid into a gas. Next, the refrigerant travels toward the compressor which constricts the gas, increasing the temperature and pressure of the refrigerant.
Third, the refrigerant moves toward the condenser located outside of the home. (This is the actual condensing unit and the only outside portion of the HVAC system AKA what most likely comes to mind when you think of A/C!) The refrigerant is exposed to the air outdoors, returning to its liquid state as the heat is absorbed by outdoor air. Finally, the refrigerant travels back toward the evaporator coil and the process repeats.
Does Air Conditioning Help or Harm Indoor Air Quality?
An A/C system is not an IAQ solution. In reality, air conditioning does little to actively improve indoor air. More often than not, A/C actually worsens indoor air quality.
The main purpose of air conditioning is to improve occupant comfort by cooling the air and regulating temperature. It does so by circulating already present air. (That is, stale and polluted indoor air, hence the need for fresh air ventilation.) It’s also common practice to close all windows and doors when the A/C is running. Albeit understandable as doing so saves money and allows the air conditioning to run effectively, it does further trap indoor contaminants.
Plus, when an air conditioning unit is not properly maintained or is run more often than necessary, indoor air quality decreases. Here are a couple ways to notice if your A/C system is worsening IAQ:
Indoor Air Pollution
If the air in your home is polluted with VOCs and allergens, your air conditioner is likely worsening the situation. Due to the fact that air conditioners recycle indoor air without purifying it, the unclean air circulating indoors further decreases indoor air quality.
Air circulation without ventilation can result in symptoms such as nasal issues, itchy eyes, headaches, dizziness or difficulty breathing. In extreme cases, asthma attacks and pneumonia may develop.
If your home’s A/C unit is constantly blowing dry cold air–your skin, eyes and nose may dry out. This can cause the skin to become itchy and flaky.
When our mucus membranes become dry, we are more susceptible to illness. This susceptibility is compounded by home air conditioning circulating polluted air. Symptoms may include dizziness, headaches and fatigue.
An air conditioning unit that is not maintained can be a hazard to those who suffer from allergies and asthma, increasing the frequency and intensity of symptoms and attacks.
Air Conditioning and IAQ Solutions Work Well Together
Of course, we do not expect you to give up your A/C. Nor are we suggesting it. Rather, it’s crucial to understand that an air conditioning unit is just one piece of the puzzle. An HVAC system in toto consists of various parts and mechanisms. By itself, an A/C unit cannot contribute to healthy indoor air quality. However, when the unit is complemented by additional devices that install directly and work with the HVAC system, indoor air quality thrives.
Solutions such as a whole-home humidifier, dehumidifier, ERV or HRV, upgraded MERV 13 air filter, air purifier or an indoor air quality monitor will work hand-in-hand with HVAC systems to improve indoor air quality. And that’s why IAQ control options are a helpful add-on for your home!