Last August I was called to a house off Bethelview Road for an AC that "ran all day and never cooled." The system was three years old. The filter had not been changed in ten months and was nearly solid with dust and pollen. A new filter and ten minutes later, the house started cooling again.
That call is common, and it is why I tell every homeowner: the filter is the cheapest, easiest thing you can do for your system.
The quick answer
| Household | Change a 1-inch filter every |
|---|---|
| One or two people, no pets | 90 days |
| Family, no pets | 60 days |
| One pet | 45 – 60 days |
| Several pets | 30 days |
| Allergies or asthma in the home | 30 days |
| Construction nearby or a brand-new home | 30 days |
| 4- to 5-inch media filter | 6 – 12 months |
In a new home, change the filter at 30 days even if it looks clean. Construction dust hides everywhere.
Why Forsyth County is hard on filters
Pollen. From mid-March through May, the pollen that turns cars yellow also loads your filter. Check it every two weeks during peak season.
Humidity. Homes near Lake Lanier and on shaded lots run more humid, and a loaded filter in a damp return is not where you want dust sitting.
Construction. New subdivisions and road work along GA-400 and Peachtree Parkway put a lot of dust in the air.
How to tell it is time
- Light test. Hold the filter up to a light. If you cannot see light through it, change it.
- The system runs longer. Weak airflow at the vents and longer run times are often the filter.
- The bill jumps. A clogged filter makes the blower work harder.
- More sneezing indoors. A loaded filter stops catching and can shed dust back into the air.
MERV ratings without the confusion
| MERV | What it is | Our take |
|---|---|---|
| 1 – 4 | Thin fiberglass | Protects the equipment, little else |
| 5 – 8 | Basic pleated | Fine for many homes |
| 9 – 12 | Better pleated | The sweet spot for most Cumming homes |
| 13 – 16 | High filtration | Good for allergies; ask us first on older systems |
Higher is not always better. A very restrictive filter can choke airflow on a system that was not designed for it.
1-inch or media filter?
A standard 1-inch filter is inexpensive but loads fast. A 4- or 5-inch media filter sits in its own cabinet, catches more and lasts 6 to 12 months. If your system has no media cabinet, we can usually add one.
Make it a habit
- Write the install date on the filter frame.
- Set a repeating reminder on your phone.
- Buy a few filters at once so a spare is always on hand.
Our maintenance visits replace a standard 1-inch filter each spring and fall, but between visits the filter is the homeowner's job.
If it has been way too long
Turn the system off, swap in a fresh filter with the arrow pointing toward the equipment, vacuum the return grille, and turn it back on. If cooling or airflow does not improve within a day or two, call us; a long-clogged filter can leave a frozen coil or a dirty blower behind.