GuidesFilters
Air Filter Size in Las Vegas: How to Read the Frame and Why Dust Wins
The right air filter size is not a guess and not “whatever the hardware store had open.” It is printed on the filter frame as length × width × thickness (for example 16×25×1). A filter that is too small bypasses dust. A filter that is too thick or too restrictive for your cabinet can starve the blower and help cause freeze-ups, limit trips, and short cycling.
Colton Air Conditioning schedules service Monday–Friday, 8am–5pm. This page is how to size and change a filter — not a product catalog.
How to read the size
- Turn the system off at the thermostat.
- Open the filter slot at the return grille or at the air handler / furnace cabinet.
- Slide the old filter out. Read the size printed on the cardboard frame.
- Note the airflow arrow. The new filter’s arrow should point toward the blower (usually toward the equipment, away from the return grille).
- Buy that exact size. “Close enough” is not enough.
If the print is gone, measure the filter itself in inches — length, width, and depth — or measure the slot carefully. Do not smash a thicker filter into a 1-inch rack.
Common sizes (examples, not your size)
Valley homes use many sizes: 16×20×1, 16×25×1, 20×20×1, 20×25×1, 14×25×1, and thicker media cabinets (4–5 inch) on some systems. Your frame wins over any list on a website.
Two-system Summerlin and similar two-story homes often have two filters — one per system. Change both.
Desert dust changes the schedule
The same blower that cools most of the year loads the filter with dust even when the furnace barely runs. A filter that looked fine in a humid climate can be gray or collapsed here in weeks during heavy cooling season.
There is no single Colton-published day count that fits every house. Pull it and look. Gray, collapsed, or sucked against the grille means replace it. Waiting until the carton says “90 days” is how people get no-cool and no-heat lockouts.
Related: heater not working, AC running but not cooling.
MERV and “more filtration” is not always better
Higher MERV captures smaller particles and can also raise static pressure. A high-MERV filter in a system that cannot handle it reduces airflow. If a high-MERV filter came with pressure problems, freeze-ups, or a loud blower, step back to what the equipment was designed for and ask during a visit — do not keep stacking restriction.
What a bad filter does to the system
| Symptom | How a packed or wrong filter contributes |
|---|---|
| Weak airflow / hot rooms | Starved supply air — [ductwork problems](/guides/ac-not-keeping-up) |
| Ice on the coil | Low airflow across the evaporator — [frozen AC coil](/guides/frozen-ac-coil) |
| Furnace short cycling | High-limit trips from poor airflow — furnace short cycling |
| Dust right after a change | Wrong size bypassing, or ducts leaking |
When to call
Call when filters are the correct size and still you have ice, no cool, no heat, water at the air handler, or breaker trips — the filter was the first check, not the whole diagnosis.
Hours are Monday–Friday, 8am–5pm.
FAQ
Where is the size printed?
On the cardboard edge of the filter — three numbers in inches.
Can I wash a disposable filter?
No. Replace it. Washable filters are a different product and must match what your cabinet expects.
Do I need a different size for winter?
Usually no. Same size year-round unless you changed equipment or the filter rack.
What hours can I reach Colton?
Monday through Friday, 8am to 5pm.
Correct filter and the system still fails? Call Colton Air Conditioning at (702) 738-6976 Monday–Friday, 8am–5pm. Tell us the symptom and what filter size you run. We will tell you if we can see it.
Colton Air Conditioning · Las Vegas Valley residential HVAC · Monday–Friday 8am–5pm
Call (702) 738-6976 or Book Online. License 0092120. Hours Monday through Friday, 8am to 5pm. Saturday and Sunday are closed.
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