There was a time when windows and doors of a house were considered the means of ventilation. Ventilation means allowing the passage of enough air from outside to enter your house and removing the stale air from inside. Adequate ventilation is essential for good health of the occupants. However the number and size of openings varies from house to house with the builder, the building design, and the materials used. The result is under-ventilation or over-ventilation. This in turn leads to unhealthy indoor air, energy loss, drafty buildings, and movement of moisture into wall assemblies. Therefore mechanical ventilation is a better option which ensures that optimal quality of air gets into house free of dust and other aerial contaminants.

 Low ventilation leads to increased level of moisture and pollutants in a home. It is not a practical idea to constantly inspect the indoor air for dangerous level of pollutants. The best protection is having background ventilation to constantly remove indoor air and replace it with fresher outdoor air. And this job is done by the HVAC and its ventilation duct.

 In all houses heating and cooling unit eats up the largest chunk in the energy-use pie chart. Therefore it is more than important to make the insulation in the house foolproof to prevent wastage of costly energy. The HVAC system with its duct work and other paraphernalia should be designed so that it will not allow seepage of air to the surrounding and at the same time allow external air to make its way inside the house in order to replace the stale air. Proper ventilation keeps issues such as mold, wood decay, rusting, at bay. Poor ventilation can lead to ill-health of the occupants who can contract allergies, pneumonia, fatigue, nausea, dry eyes, headaches and nasal congestion. It can cause frosting and bad odor in the house. It will make your machine work harder to keep up the cooling level which will cause rapid wear and tear.

 How to ventilate a system?

When you have to install ventilation equipment it is better to ensure that the duct is up-sized an inch or two to allow enough flow of air. Remember if your duct is constricted, the fan will not work to deliver the rated airflow. A property sized duct will allow the fans to provide more airflow with minimal noise. Also the duct surface should be smooth and it should be straight as far as possible without much twists and turns. The larger is the duct diameter, the greater the airflow.

 Rigid duct always have an advantage over flex duct when it comes to ventilation. These ducts allow better airflow. They have a smooth surface. The flex duct soften get kinked and twisted causing bumps for the air.

Always avoid designing a bend or elbow very close to the fan. This will reduce static pressure and fan noise. In metal ducts wide-sweep elbows should be used to reduce the resistance to airflow. Buy a fan that is certified at 0.25 in. w.c.;older fans are certified at 0.1 in. w.c, which was the old standard. Avoid long duct runs and sharp turns.