HVAC Filters Need The Install Date

The filter drawer needs a Sharpie next to it. Not in the office. Next to the filters.

My version:

• write the month on the cardboard before sliding it in
• keep the filter size in Obsidian, not on a receipt somewhere
• buy one spare when the last spare goes in
• check it before Seattle smoke season, not during the first bad-air week

The date matters because “I changed it recently” is a useless measurement. Recently can mean May. It can also mean last winter, before three rounds of construction dust, dog hair, and open-window pollen.

This is a two-minute chore if the marker and spare filter are already there. It becomes a fake research project when the furnace closet is empty and the old filter is too gray to defend itself.