HVAC runs on weather extremes. The first genuine heat wave and the first hard freeze compress a month of demand into a week, phones overload, and the jobs go to whoever is findable and answering. Between the peaks sits the quieter, better-margin half of the business: maintenance agreements, indoor air quality, and system replacement that a homeowner has been deferring for two seasons.
Replacement is where the real money is, and it is a slow, comparison-heavy decision — financing, efficiency ratings, brands, multiple in-home quotes. Repair is the opposite: instant, local, decided by a phone screen.
A plan that only chases the peaks burns budget at the worst possible cost-per-click and ignores the part of the book that makes the year predictable.