The answer to 'how to maintain replacement' is to regularly clean and inspect your HVAC replacement unit. This includes changing the air filter every 1-3 months, cleaning the condenser coils annually, and scheduling professional tune-ups and inspections every 6-12 months.
Proper maintenance will help extend the lifespan of your replacement unit, improve energy efficiency, and ensure it continues to operate safely and effectively. Be sure to follow the manufacturer's recommended maintenance schedule and guidelines.