We just bought a modular home and are in the process of cleaning/moving in. It is a 2004 model and has a Miller hvac system on the back left side of the house when facing the front. The bedroom on the front at other end of the heatpump (right side when facing the front) is cool/warm air.The vents are in the floor and open i took the covers off of all to clean and vac. Has not helped. I know that a fan is made to go into the duckwork to pull air into rooms. Is this hard to install or do i need to do something else thanks