Upkeep
The Furnace Filter Has an Owner: Schedule, Size, Swap, and Who Buys the Next One
A filter nobody changes makes the furnace work harder and the house dustier, so settle who owns the swap, what size to buy, and where the spare lives before the next cold or hot stretch.
The filter is the easiest part of the heating and cooling system to forget. It does not announce itself, and nobody thinks about it until the air feels heavy or the system starts running longer than it should. When you are the one home all day and she is the one sitting in the room, that dust is your problem to manage, so make the swap someone's job.
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.
Read the size off the frame
Pull the filter out and read the size printed on the cardboard edge. Write that size on a card and tape it inside the closet where you keep the spares. Also note the arrow on the frame. It shows which way the air should move through the filter, and a filter installed backward does less work than it should.
Follow the schedule on the package
Each filter package prints a change interval. Use that number as the starting point, then shorten it if you have pets, a lot of dust from construction, or a dusty season outside. Set a reminder on the same phone you use for appointments. A filter swap that lives only in your head will slip the first week you are on no sleep.
Decide who swaps it
Name one person for the swap. If you do it, write your name on the calendar. If a hired helper or a family member does it, show them the arrow and the size once, then leave the spare where they can find it without asking. Do not hand it to whoever is nearest on the day it is due.
Keep a spare on the shelf
Buy the next filter when you change the current one, not when the house starts to smell. Keep it in the same closet as the size card. A furnace that runs with a clogged filter is also harder to hear, so pay attention if the airflow from the vents drops or the room feels stuffier than usual.
Tie it to the thermostat
The person who sets the thermostat is usually the person who notices a problem first. Keep the thermostat setting on the same note as the filter schedule. If the room is too hot or too cold for her, that is worth reporting to the company that services the system, along with the filter size and the date of the last change.