DIY Tests to Check if Your Refrigerator Air Filter Is Still Effective
You open the fridge door expecting that fresh, clean smell – but instead you get a whiff of yesterday's garlic or a faint musty note. Before you run out to buy a new air filter, a few quick DIY tests can tell you if the current one is still pulling its weight.
Refrigerator air filters trap odours, ethylene gas from produce, and airborne bacteria to keep food fresher longer. They sit in ceiling grilles, rear walls, or hidden panels depending on the model. The goal is simple: determine whether the filter is saturated or still working without waiting for smells to become unbearable. Here are reliable DIY methods using smell and visual checks – no tools required.
Smell-Based Tests
These are the most direct – your nose knows when something's off.
Onion or Garlic Overnight Test
Place a cut onion or garlic clove in an open container inside the fridge overnight. Next morning, open the door and take a deep sniff.
- Fresh or neutral smell? Filter is still effective.
- Strong onion/garlic odour lingers? Filter is saturated – time to replace.
This test mimics everyday food odours and is one of the most reliable. A friend of mine did this with his LG fridge – the onion smell was gone the next day for months, then suddenly came back strong. He replaced the filter and it fixed it immediately.
Produce Ripening Test
Put a banana or apple in the crisper drawer. Check it after 3–4 days.
- Banana ripens normally or slowly? Filter is trapping ethylene gas.
- Banana turns brown or softens much faster than usual? Filter is no longer effective at controlling ethylene – replace it.
This test shows real-world impact on food life – especially noticeable in high-humidity homes where ethylene builds up quickly.
General Sniff Test
Open the door wide and take a deep breath inside.
- Clean, neutral, or slightly cool air? Filter is likely still good.
- Stale, musty, lingering food smells, or faint chemical odour? Filter is overdue – replace or deep clean the compartment.
Do this weekly – early detection prevents bigger issues.
Visual and Physical Checks
These complement smell tests and catch problems you might miss.
Shine a flashlight into the filter compartment (ceiling or rear).
- Clean, light-colored filter? Still effective.
- Dark, discolored, dusty, or black spots (mould)? Saturated or contaminated – replace immediately.
Feel the airflow near the vents (usually ceiling or rear).
- Steady, cool air movement? Filter and fan are working.
- Weak, uneven, or warm air? Dust buildup or clogging – clean or replace.
In humid areas, look for moisture or condensation inside the compartment – that accelerates saturation.
Competitors and Brand Notes
GE ODORFILTER: Onion test works well – replace when smell returns.
Frigidaire PureAir: Visual mould spots common in humidity – check monthly.
Whirlpool FreshFlow: Produce test shows ethylene issues fast.
LG LT120F: Antimicrobial layer – smell test may pass longer, but visual check still matters.
Samsung DA97: App alerts pair with physical sniff test.
Generics from Tier1 or Glacier Fresh saturate faster – test more often.
For full air filter care, see our Installation, Maintenance, and Troubleshooting for Refrigerator Air Filters. For signs it's overdue, check Common signs your refrigerator air filter is overdue for replacement. For habits to extend life, see Extending refrigerator air filter life with simple habits.
Wrapping Up
DIY tests like the onion overnight or produce ripening check tell you quickly if your refrigerator air filter is still effective – no waiting for bad smells to take over. These methods work across brands and climates. Our shop has filters – fresher air awaits.
