The cheapest capacity upgrade in a Fayetteville house is a filter that is not a felt pad.
Where it is
Usually a large return grille in a hallway, or a slot at the furnace / air handler in a closet or garage. Some houses have more than one. The arrow on the frame points toward the equipment, not toward the room.
Turn the system off at the thermostat so the blower is not trying to eat the filter while you tug.
The test
Hold it in front of a bright window or a flashlight.
- Light comes through the pleats in a fairly even way: still working.
- Gray, hairy, caked, or almost no light: replace it.
- High-MERV filters look darker even when new. If it is dusty to the touch or the system has been running long with weak air, replace it anyway.
Write the size printed on the cardboard. That is the only size that fits.
How often
Monthly in cooling season if you have pets, construction dust, or a house that runs all afternoon. Quarterly is a rumor started by a four-pack at the grocery store. Look. Do not count shopping trips.
A clogged filter does not just “cost efficiency.” It ices coils in summer and trips furnaces on limit in winter. That is how a $12 part becomes a no-cool Saturday.
Membership includes the visit. You still own the monthly glance.