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Why Does the Air Feel Thick in My House?


Stale air is difficult to describe, but you recognize it when you encounter it. Thick, stuffy air is a more serious indoor air quality issue than most people realize. If the air in your home doesn’t smell fresh, it isn’t. We’ll explain below why the air feels thick in your house and why it’s important to address the situation.

What Makes Air Feel Thick, Stale, and Stuffy?

High humidity alone can make the air feel thicker and stuffier. The extra moisture can make it feel warmer and stickier. It’s also a sign your HVAC system isn’t doing its job. Aside from providing heating and cooling, the system condenses and drains moisture. If your home is more humid, the unit should be checked for issues like a clogged condensate drain line, dirty coil, or blocked filter.

But stale air is more than about excess moisture.  A combination of factors can cause an unpleasant odor. Here’s what can contribute to the telltale scent of stale air:

Carbon Dioxide

We exhale carbon dioxide (CO2) with every breath. If there’s a lack of ventilation, CO2 can build up and cause the air to feel stuffy. High carbon dioxide concentrations can make you feel drowsy or fatigued and can cause headaches, nausea, and eye and throat irritation. It’s known to reduce productivity and, according to some studies, may be one of the potential causes of “Sick Building Syndrome”.

Microbial Volatile Organic Compounds (MVOCs)

Often caused by the growth of bacteria and fungi, MVOCs are carbon-based molecules that can trigger strong odors even in low concentrations. Metabolic waste products from microorganisms can create musty and ammonia- and sulfur-like odors. A consistent presence of moisture and lack of ventilation can cause MVOCs to build up and make the air feel thick and stale. 

Why Is Stale Air More of a Problem in Modern Homes?

Buildings are designed differently than they were in the past. Older structures allowed more outside air in, which helped filter old air. But this wasn’t energy efficient, especially where the temperature difference between outdoor and indoor air was greater. A tighter envelope improves efficiency and lowers electric bills but reduces air filtration, making you more likely to encounter stale, thicker-feeling air. 

What to Do When the Air Feels Thick in Your House

An increase in humidity and CO2 in an enclosed crowded room, caused by people breathing, is enough to make the air feel stale. Brief exposure is typically not dangerous. But consistent exposure to some pollutants can be harmful or, at the very least, lead to chronic coughing, fatigue, headaches, and eye, nose, and throat irritation.

You’ll need to ventilate the room to freshen up the air. Opening windows is often effective. You can also turn on ceiling fans to promote circulation, while some window fans pull stale air out of a room. In enclosed, moisture-prone rooms like the bathroom, kitchen, or laundry room, exhaust fans can help eliminate stale air.

Another solution is to schedule professional maintenance. A technician can inspect, clean, and repair your HVAC system so it doesn’t contribute to indoor air quality issues. And clean or change air filters at least every 60 days. However, installing a high-efficiency particulate air (HEPA) filter helps eliminate some of the smallest airborne particulates.

Monarch Home Services Can Help Improve Indoor Air Quality

If the air feels thick in your house, our licensed technicians can employ various methods to improve indoor air quality. We install air filtration systems, air scrubbers, and ductwork as well as clean and seal ducts to address air quality issues. To get started, request service online or call (661) 215-6580.

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