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How Often You Should Change the Air Filter in Your Iowa Home
If you're wondering how often to change your furnace filter, start with the filter in your system. A 1-inch pleated filter commonly needs replacement every 60 to 90 days. Thicker 4- or 5-inch media filters last several months.
Pets, smoking, construction dust, and heavy heating or cooling use shorten that schedule. During an Iowa winter, check your filter monthly. If you're not sure which filter fits your system, we will check the size and type during an air filter replacement visit.
The Short Answer: Replacement Intervals by Filter Type
Use this schedule as a starting point. Follow the instructions for your filter and HVAC equipment if they call for a different interval.
| Filter Type | Normal Home | Pets, Allergies, Heavy Winter use |
|---|---|---|
| 1-inch fiberglass | 30 days | 30 days |
| 1-inch pleated, MERV 8-11 | 60-90 days | 30-45 days |
| 2-inch filter | About 90 days | 45-60 days |
| 4-inch media filter | About 6 months | 3-4 months |
| 5-inch media filter | 6-12 months | About 6 months |
| Washable filter | Check and clean monthly | Check and clean monthly |
What Changes the Schedule
Every time your HVAC system runs, your filter catches dust and debris pulled in with the return air. Pets, cigarette smoke, remodeling work, nearby construction, and running your HVAC fan continuously load the filter faster.
Around Grimes and the outer Des Moines metro, harvest activity can put extra dust in the air during September and October. From November through March, your furnace may run for long stretches during cold weather. Check the filter monthly during these periods instead of relying only on the installation date.
If you put in a clean filter and heavy dust keeps returning, the filter is not the only place to look for indoor air quality problems.
Signs Your Filter Is Overdue
Pull your filter out and look at the side facing the incoming air. If the pleats are heavily coated in gray dust and debris, replace it.
Other signs that may occur when a filter is heavily clogged include:
- Airflow from your registers feels weaker.
- Your furnace or AC runs longer to reach the thermostat setting.
- Your system begins running longer or cycling differently than usual.
- Dust settles around your home soon after cleaning.
A dirty filter restricts airflow and forces your heating or cooling system to work with less air moving through it. If you install a clean filter and airflow is still weak, the filter was not the whole problem.
If you find heavy debris inside the return duct while changing your filter, we will inspect the ductwork before recommending duct cleaning.
What a Clogged Filter Actually Does to Your System
Your furnace and AC both depend on unrestricted airflow.
During cooling season, a clogged filter cuts airflow across your indoor coil and increases the risk of a freeze-up. During heating season, restricted airflow raises the risk of your furnace overheating and tripping its safety limit.
Your blower is still trying to pull air through that clogged filter, which puts extra strain on the motor. If you put in a clean filter and your furnace still has weak airflow, repeated cycling, or trouble heating your home, schedule furnace maintenance so we can find the cause.
Choosing the Right MERV Rating
The MERV number tells you how much your filter is designed to catch as air passes through it. A higher number means finer filtration, but that does not automatically make it the best filter for your system.
Your furnace or air handler still needs enough airflow through the filter. Before moving to a higher MERV rating, check the filter requirements for your equipment. A filter that is too restrictive for your system reduces airflow.
How to Change It
Changing a standard disposable HVAC filter only takes a few steps:
- Turn your HVAC system off.
- Find the filter and check the airflow arrow on the old one.
- Pull the old filter out.
- Install the new filter with its arrow pointing in the direction of airflow.
- Write the installation date on the new filter frame.
- Turn your system back on.
If the new filter does not slide into the slot correctly, check the dimensions before forcing it into place.
Let Greens Handle It
If you are unsure when to change your HVAC filter, or a new filter does not fix weak airflow, Greens Appliance, Heating & Cooling can check your system. We have served the Des Moines area since 1958.
With our priority maintenance plan, we check your filter during scheduled HVAC visits and let you know when it needs to be replaced.
Schedule Online(515) 532-7974