HVAC leads follow the weather. The first hot week brings AC repair requests from people whose system will not cool; the first cold snap brings furnace calls. Between seasons you see homeowners planning a replacement for an aging system, asking about heat pumps, adding a mini-split to a room that never stays comfortable, or looking for a maintenance plan after a big repair bill.
A homeowner with no cooling or heat wants someone at the door today or tomorrow, and will keep calling until they get it. Replacement shoppers want a fair price, financing options and a crew they trust. In both cases speed decides who gets the job: the first company that answers and offers a real time slot usually wins the visit.
Homeowners can approve a replacement; renters usually call their landlord, so filter on homeowner status. System age is the best single signal you have: an old system with a repair request is often a replacement in disguise, while a newer one points to a service call. Timeline tells you whether to dispatch now or book a sales visit.