The filter in the furnace or air handler does its job until it clogs. Then the system works harder, the air moves less, and dust settles where it should not. Nobody sees the filter unless someone opens the cabinet. From far away, the trick is to turn a vague chore into a named job with one owner and one reminder.
Local option: New Plan Care gives families in the St. Louis area in-home help so a parent can stay home: companionship, help with bathing and dressing, meals, and overnight care. Call (314) 405-0887.
Find the filter and its size
Ask someone in the house, or ask her to point at it on a video call, to find the filter slot. Most filters print their size along the edge of the cardboard frame. Photograph the printed size, the arrow that shows airflow direction, and the slot itself. Put the photo in the shared folder. The size and the airflow arrow are the two things that matter when a new filter comes home from the store. Do not guess from the old one, since a rough cut can leave gaps around the edge.
Name the owner
Decide who buys the filters, who swaps them, and who checks the date. Those can be three different people, but each job needs a name. One common split is a sibling who orders on a set schedule, a helper in town who swaps during a visit, and you, who gets the reminder. If nobody local can swap a filter, the swap can wait for your next trip, but the buying should not wait. The Local Help for a St. Louis Parent page lists the kinds of help to look for close to home.
Set the schedule where it will be seen
Pick a schedule your household will actually keep. Attach it to a date that already gets attention, like a bill or a season change, and set one repeating alert on the phone that both the buyer and the swapper receive. After each swap, write the date on the filter frame with a marker. The date on the frame answers the question nobody remembers.
What a helper can and cannot do
A hired helper who comes in for a few hours can slide out the old filter, check the arrow, and put in a new one if you have left it by the door. That is a household errand. Anything that involves the furnace panel, the gas line, or a service light belongs to the furnace company. Tell the helper where to stop, and write that down too.
Tonight
Ask someone in the house to photograph the filter slot and the printed size, send the photo to the shared folder, and set one calendar alert for the next swap date. If nobody is near the furnace, ask the person who visits most often to take the photo.
For the doctor
If she has a breathing condition or allergies, ask her doctor whether any change in the filter matters for her, and bring that question to the next appointment rather than deciding alone. Until then, keep the schedule the same.