Ask most homeowners where the thermostat is and they will point to a hallway, a stairwell landing, or the wall between the kitchen and the dining room. That spot is picked for a clean wall and easy wiring, and it is a fair place to read the average air in a house. It is a poor place to judge the comfort of one person who spends the day in a recliner near a north-facing window.
The same gap shows up in trade news. ACHR News covered a HARDI survey of HVACR distributors that reported a "9% jump in September" in sales, with 12-month growth at 3.7%, in its report on the September distributor survey. A survey like that is a trade measure. It tells you how the industry's sales moved in September 2026, not whether the chair by your window is warm tonight. Measure the room that matters to the person living in it.
Read the Room Where Someone Sits
Use a plain digital thermometer with a min/max memory, the kind sold for kitchens or garden beds. Set it on a small table at about the height of a seated person's head, away from the window glass, the exterior wall, and any supply register. Leave it for a full day, then record the minimum and maximum. Read the thermostat at the same moments so you have two numbers to compare.
The gap between those numbers is the useful part. A room several degrees cooler than the thermostat on a windy night often points at the building envelope, meaning leaky windows, a cold exterior wall, or a poorly sealed rim joist, rather than at the furnace schedule. Write the gap down and watch how it changes with the weather.
Check the Supply Before You Blame the Setpoint
With the furnace running, put a hand over the supply register in that room. Warm air should be clearly felt within a few minutes of a heating cycle. Look for a closed damper, furniture or a rug covering the grille, and a return grille so dusty it can barely pull air. A clogged filter cuts airflow too. Do not block a register to see what happens, and do not raise the setpoint to make up for weak airflow. If the register is weak or cool while the furnace runs, the problem sits in the ductwork or the equipment, and that calls for a licensed heating contractor.
Keep the Log on Paper
Make a one-page log with columns for date, time, thermostat reading, chair reading, outdoor temperature if you know it, register feel (warm, lukewarm, or cool), and what changed that day. Keep it on the refrigerator or in the folder with the furnace paperwork. Date every line, even when nothing changes, because a flat line is also data. A month of entries shows a pattern that one reading cannot.
Who takes the readings matters too. A relative who lives elsewhere can photograph a thermometer and text the number. Families who arrange a visiting helper, such as through non-medical in-home support for older adults in St. Louis, can ask that person to read the chair thermometer at the start of each visit and write the number down. The helper observes and reports. The family decides the thermostat setting, the repairs, and what temperature suits the person, and any question about health belongs with the person's doctor. A homeowner's log is not medical advice.
When to Call Someone
Call a licensed heating contractor if the room with the chair stays below the level the family has set even with good register flow, if the furnace short-cycles, or if the air at the register stays cool for long stretches while the burner runs. Bring the log. A contractor who sees two columns of numbers and a register note can start with the right question instead of guessing.
Winter tests the chair, not the hallway. Measure where someone sits, and the thermostat stops being the only witness in the house.