The answer to 'difference between replacement and' is that replacement refers to installing a completely new HVAC system, while repair involves fixing or replacing specific components of an existing system. Replacement is typically done when an older system is no longer energy-efficient or reliable, while repairs are done to extend the life of a system that still has useful life remaining.
Replacement offers benefits like improved energy efficiency, better indoor air quality, and a longer lifespan, but has a higher upfront cost. Repairs are generally less expensive but may not provide the same long-term benefits as a full replacement. The best option depends on the age and condition of your existing HVAC system, your budget, and your long-term goals for your home.