The Truth About Cheap Filters and Your Airflow
The main job of any air filter is to keep the entire heating and cooling system clean and running smoothly. However, most cheap 1-inch filters use a loose, large-weave material that primarily traps only the biggest particles. This means:
- Poor Indoor Air Quality (IAQ): A cheap filter allows smaller, more dangerous particles to pass right through and continue circulating in your home—and into your lungs.
- System Contamination: Over time, these fine particles build up on the HVAC system’s blower motor and evaporator coil, reducing efficiency, straining components, and potentially leading to expensive repairs.
Think about what’s actually floating in your home’s air: dust mites, pet dander, mold spores, bacteria, viruses, and human skin particles. A low-grade filter can’t stop most of these tiny contaminants.
📈 Understanding MERV: The Key to Air Filtration
To understand filter quality, you need to know the MERV rating (Minimum Efficiency Reporting Value). This rating scale (typically 1–16 for residential use) measures how effectively a filter captures particles of different sizes:
| MERV Rating | Particle Size Trapped | What It Captures | Typical Residential Use |
| 1–4 | Larger than 10 μm | Pollen, lint, carpet fibers | Basic filtration (often cheap, fiberglass filters) |
| 8–11 | 1.0 – 10.0 μm | Mold spores, pet dander, fine dust | Good balance of air cleaning and system protection |
| 13+ | 0.3 – 1.0 μm | Bacteria, smoke, viruses, sneeze droplets | High-efficiency, best for allergy/asthma sufferers |
A cheap filter is usually a low MERV filter (4 or less). For better air quality, you should aim for a MERV 8 or higher, if your HVAC system can handle it.
🥇 The Case for Media Air Cleaners (Thicker Filters)
The best solution for superior indoor air quality and HVAC protection is often a media air cleaner that uses a thicker filter.
- Superior Filtration: These filters are often 4 to 5 inches thick, offering a much larger surface area than 1-inch filters. This increased surface area is critical because it allows for a higher MERV rating (like MERV 11 or 13) without severely restricting airflow—a common issue with high-MERV 1-inch filters.
- Longer Lifespan: A 5-inch media filter can last for 6–12 months before needing replacement, compared to changing a 1-inch filter every 1–3 months. This saves you time and ensures consistent performance.
- High-MERV Performance without Airflow Issues: Because of their depth, media filters can maintain optimal system airflow and efficiency while capturing viruses, bacteria, and mold that can make you sick.
💨 Want Odor Control?
For homes concerned about odors from cooking, pets, or smoking, we recommend a carbon-coated media filter. The activated carbon absorbs odors as the air passes through, providing a cleaner, fresher smell to your indoor air.
🛠️ Installing Your Filter Correctly
Whether you use a standard or media filter, correct installation is simple but crucial:
- Check the Arrow: Always look for the arrow printed on the filter frame. This arrow must point TOWARD the furnace/air handler (in the direction of the airflow).
- Slide and Secure: Slide the new filter into place until it fits snugly.
- Record the Date: Write the current date on the filter’s frame or note it down so you know exactly when to check it again. Don’t wait until you see one of the Five Signs of a Dirty Furnace Air Filter—change it proactively!
Read Five Signs of a Dirty Furnace Air Filter
The bottom line: Cheap furnace filters are not better. They are merely the minimum standard for protecting your equipment. If you want to protect your family’s health and ensure your HVAC system runs at peak efficiency, investing in a high-quality filter or a media air cleaner is the right move.
Looking to improve the quality of indoor air? AIr purifier and whole house humidifier improves your health and immune system.
Ready to find the best air filtering solution for your home in the Joliet, New Lenox, Plainfield, Homer Glen, and Bolingbrook area? Call the oldest HVAC contractor in the area at 815-390-7095 to speak with an expert today!
