The filter in Mom's furnace is the smallest chore in the house that keeps coming back. It takes a new filter, a few minutes, and a look at a label. It also takes a store run, a stool or ladder, and somebody remembering the date. Nobody thinks of it as a job, which is exactly why it lands on the same person every season.
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.
Count the trips before you count the money
Check the size and the replacement interval printed on the filter frame or in the furnace manual, and write both down. That interval is the schedule to plan around, not a guess. Then count the changes in a year. Each one is a store run, a few minutes at the furnace, and a reminder someone has to hold. Multiply that by the number of years this arrangement is likely to last, and you have the real labor. For most families it is more than the filter itself.
What the swap actually takes
Before you decide who does it, look at the old filter. Note the size on the edge and the arrow that shows airflow direction. The new filter goes in the same direction, the panel closes, and the fan should run normally afterward. Keep one spare in the closet so the change can happen the day the old one looks dirty, not a week later when the store is closed. If the person doing the swap is the one who always does the trip, say so out loud at the meeting. That is the work, and it counts.
When the tech visit is the better call
A filter change is routine. A tune-up or inspection is a different job, because it includes checks that need a trained technician and the right tools. Book the visit when the furnace is due for service on its normal schedule, when it is short-cycling or running louder than usual, or when the heat is uneven from room to room. If you smell gas, or if a carbon monoxide alarm sounds, do not work on the furnace yourself. Get Mom and anyone else out of the room, then call the gas company or a licensed heating contractor. That is an emergency call, not a chore to schedule.
What to ask before you book
Ask whether the visit is a flat fee or billed by the hour, and whether the price includes the filter. Ask what the written report will list, so you can see what was actually checked. Ask whether the company holds the license your city or county requires for heating work, and whether a repair estimate will come to you in writing before any part is ordered. Ask who the tech should call if the work turns up more than the visit covers, and whether they will wait for your approval before adding anything. Those answers tell you more about the company than the advertised rate does.
Who lets them in
The part of this job nobody counts is the appointment itself. Someone has to be at the house, hold a key, or arrange access with Mom agreeing to the visit. Write the access plan down: which sibling is the contact, who has a key, and what happens if no one answers the door. A visit that fails at the door costs the trip twice, and the person who was supposed to be home is usually the one who gets the second call. Mom should hear what is being checked and agree to it before the tech arrives, which keeps the visit about her house and her choice.
Split it on paper
Put the filter changes, the store runs, the tune-up visit, and the access call on one list, with a name beside each line. Decide who pays for the filters, who pays for the visit, and whether those costs come from Mom's account or get shared among siblings. The goal is not to make the bill feel fair in one meeting. It is to make the labor visible, so next season does not depend on whoever happens to remember. If you want a local starting point for heating contacts or licensing questions, the Local help page lists where to begin.