Change your AC filter, and again after a dust storm
A clogged return filter is the first thing to check when the house won't cool. In Tucson, the monsoon's dust storms load a filter fast.
What to watch for: His filter sits at the furnace in a basement. Many Tucson homes have it behind a wall or ceiling grille instead. The rule is the same: the arrow points toward the equipment.
Why does this matter in Tucson?
Dust storms are one of the hazards the National Weather Service ties to the monsoon window, which runs June 15 through September 30. A storm that browns out the sky also pushes fine dust through door gaps and into your return air. That dust ends up on the filter.
A loaded filter starves the system of air. The house cools slower, the indoor coil can get cold enough to ice, and the blower works harder. A fresh filter is the cheapest fix in heating and cooling, and it's the one every pro checks first.
What you'll learn
- Where the filter lives: a wall or ceiling return grille, or a slot at the air handler
- How to read the size off the old filter frame before you buy
- Which way the airflow arrow points, and why it matters
- Why a filter needs a look after every monsoon dust storm
How do you do it, step by step?
- Set the thermostat to Off so the blower stops pulling on the filter.
- Find the filter. Look behind the largest grille on a wall or ceiling (the return), or at a slot on the air handler or furnace.
- Slide the old filter out and read the size printed on the frame (three numbers, in inches). Snap a photo of it for the store.
- Note the airflow arrow on the frame. The arrow points toward the air handler, away from the room.
- Slide in a new filter of the same size with the arrow pointing the same way. It should sit snug with no gaps around the edges.
- Write the date on the frame with a marker, close the grille and set the thermostat back to Cool or Heat.
- After a dust storm, pull the filter and hold it to a light. If you cannot see light through it, replace it.
When should you stop and call a pro?
- The filter is wet, or there is water in the return grille or around the air handler.
- There is ice on the copper lines or the indoor coil. Turn the system off and let it thaw before you run it again.
- The filter collapsed or got sucked into the system.
Before you switch to a much denser filter, ask the pro or check the air handler manual. A tighter filter can restrict airflow on some systems.
Read next
Sources and official pages
Rather have a pro handle it?
Climate Pros Tucson matches homeowners with licensed local HVAC pros across the Tucson area. You talk to us, then to the pro, and the pro quotes the job before any work starts.
What else can you check yourself?
Hose off the outdoor coil after monsoon dust
The outdoor unit has to dump your home’s heat into air that is often over 100°F. Dust packed in its fins makes that job harder.
Clear a clogged AC condensate drain
Monsoon humidity makes your AC pull more water out of the air. If the drain line is slow, that water ends up in the pan, the ceiling or the closet floor.
Set your thermostat around TEP's peak hours
If you're on a TEP time-of-use plan, when you cool matters as much as how much. The summer weekday peak is 3 to 7 p.m.