Changing your air filter is the single most valuable thing you can do for your AC — a dirty filter causes frozen coils, weak cooling, higher bills, and premature breakdowns. In a Houston home running AC most of the year, filters should be checked monthly and changed every 30–90 days. It takes five minutes and costs a few dollars. Here’s how to do it right.
Watch how it's done
Video: LRN2DIY. Shown for reference — not affiliated with GetHoustonLeads.
What you'll need
- A new filter in the correct size
- A pen (to date the filter)
Recommended parts & supplies
- HVAC air filter multi-pack — buy in bulk — check your size on the old filter
- MERV 11 allergen air filter — better dust/pollen capture
- Washable reusable air filter — a reusable option
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Step by step
- 1
Find your filter and note its size
The filter sits in the return-air grille (a large vent, often in a hallway ceiling or wall) or in a slot on the indoor air handler. The size is printed on the cardboard edge of the old filter — something like 16x25x1. Write it down or snap a photo so you buy the right replacement.
- 2
Turn the system to OFF or FAN
Switch the thermostat off (or fan-only) so the blower isn’t pulling air — and loose dust — while the filter is out.
- 3
Remove the old filter and note the airflow arrow
Slide the old filter out. Before you toss it, look at the printed arrow on its frame — it shows the direction of airflow, pointing toward the unit. You’ll match that on the new one.
- 4
Insert the new filter with the arrow pointing correctly
Slide the new filter in so its airflow arrow points the same way the old one did — toward the air handler / away from the room. Installing it backward reduces efficiency. Make sure it sits flush with no gaps around the edges for air to sneak past.
- 5
Date it and set a reminder
Write today’s date on the filter’s edge with a pen, then set a phone reminder to check it in 30 days. In Houston, homes with pets or heavy dust often need a fresh filter monthly; cleaner homes can stretch to 90 days. Checking monthly tells you your home’s real interval.
When to call a pro
Filter changes are pure DIY — no pro needed. But if you’re putting in clean filters and still getting weak airflow, warm air, or a system that freezes up, that points to a deeper issue like a dirty evaporator coil, a failing blower motor, or low refrigerant. A once-a-year professional tune-up (ideally each spring before Houston’s brutal summer) cleans the coil, checks refrigerant and electrical parts, and catches small problems before they leave you without AC in July.
Get a free quote from a local pro
No obligation — a licensed, insured local River Oaks partner will reach out. Available 24/7 for emergencies.
How to Change Your AC Air Filter (and Why It Matters So Much) — FAQ
How often should I change my AC filter in Houston?
Does a dirty air filter really damage my AC?
Which way does the arrow on the filter go?
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