Where to put them on the equipment
The rule is simple: put it where someone will be standing when they need your number. On a furnace or air handler, that is the cabinet door at eye level — not the side panel that faces the wall. On a water heater, the front near the controls. On a condenser, the service panel rather than the top, where debris and standing water collect.
Keep it clear of data plates, model and serial labels, and anything a future tech or inspector needs to read. Wipe the panel down first; a permanent adhesive only performs on a clean, dry, flat surface.







