Why is indoor air quality a particular issue in central Iowa?
Three regional factors stack up. First, agriculture: seasonal field work puts dust and particulates in the air across Polk, Dallas, and the surrounding counties, and it finds its way indoors. Second, our extremes — homes here are sealed tight against January cold and August humidity, so for much of the year there is very little natural air exchange.
Third, radon. Iowa has the highest average indoor radon levels of any state in the country, driven by our glacial soil geology. That is a genuine public-health issue rather than a sales angle, and testing is inexpensive. The EPA action level is 4.0 pCi/L, and mitigation is a well-established fix.
What filtration actually helps?
MERV rating measures how effectively a filter captures particles. Higher is not automatically better, because a dense filter in a system not designed for it restricts airflow, which hurts both comfort and equipment life.
Choosing a filter without starving your system
- MERV 8: basic dust and lint protection; safe in nearly any system
- MERV 11-13: captures much finer particles including most pollen and some smoke; a good target for allergy households
- MERV 14+ or true HEPA: high capture, but usually needs a dedicated media cabinet or bypass unit, not a slot filter
- Media cabinets (4-5 inch): higher capture with far less airflow penalty than a 1-inch filter of the same MERV
- Check monthly during heavy-use months; a restricted filter is the most common cause of both no-heat and no-cool calls we run
How does humidity affect air quality?
Humidity is the lever most homeowners overlook. Below about 30% relative humidity — normal in an Iowa house running a furnace all winter — you get dry sinuses, static, cracking woodwork, and more airborne dust. Above roughly 50%, you create conditions for dust mites and mold growth.
Whole-home humidifiers address the winter side; proper AC sizing and, in some basements, dedicated dehumidification address the summer side. This is another reason oversized cooling equipment causes trouble: it cools without dehumidifying.
Are air purifiers and UV lights worth it?
They are a supplement, not a foundation. Whole-home air cleaners integrated into the ductwork can meaningfully reduce fine particulates, and UV lamps aimed at the evaporator coil help keep that coil biologically clean, which protects airflow. Both are reasonable additions to a well-maintained system.
What they will not do is fix a moisture problem, seal leaky ducts pulling air from a dusty crawlspace, or reduce radon. We would rather sell you the filter upgrade and the humidity fix that solve most complaints than an accessory that treats the symptom.
Frequently asked questions
How often should I change my furnace filter?
For a standard 1-inch filter, check monthly and expect to change every 1 to 3 months — more often with pets, allergies, or during heavy pollen and harvest periods. A 4-inch media filter typically lasts 6 to 12 months. The right interval is the one where the filter looks loaded, not the one on the package.
Should I test for radon in Iowa?
Yes. Iowa has the highest average indoor radon levels in the United States, and levels vary house to house even on the same block, so a neighbor's result tells you nothing about yours. Short-term test kits are inexpensive and widely available, and mitigation systems are a routine, well-understood fix if your result comes back at or above 4.0 pCi/L.
Will a higher MERV filter damage my furnace?
It can, if the system was not designed for the added resistance. A MERV 13 filter in a slot sized for MERV 8 can restrict airflow enough to trip the high-limit switch in heating or freeze the coil in cooling. The safe path to high filtration is a deeper media cabinet, which increases surface area so capture goes up without the pressure penalty.
Does duct cleaning improve air quality?
Sometimes, and it is oversold. It genuinely helps after renovation dust, a rodent problem, or visible contamination. In an ordinary, well-filtered home it makes less difference than upgrading filtration and fixing humidity. We will tell you honestly which situation your ducts are in.
Keep Learning