The most cost-effective combination filter and fresh air entry system on the market today!

When Pure Air Systems, Inc. first introduced the 600HS unit in 1985 we offered the option of introducing outside, filtered fresh air with the unit. Today, the ability to introduce filtered, fresh outside air provides for better air ventilation and pressurization for homes and commercial facilities, which is EASY TO DO.

Simply by adding a 6″ duct from the outside to the inlet of the HEPA, Shield units, you can now have both the best filtration system and the ability to introduce outside, fresh filtered air pressurization and ventilation. You can introduce from 50 CFM to 100 CFM (depending upon the HEPA Shield unit you choose) of outside air providing for 72,000 to 144,000 cubic feet of air into the home or indoor environment PER DAY. This approach allows for pressurization of the home or indoor environment which eliminates the entry of fine particulate, gases and odors whenever your HVAC system fan is running.

Introducing 50 CFM of outside air (3000 cubic feet per hour) has no negative affect on the performance of the HVAC system as it represents approximately 3% to 5% of the total air volume going through the HVAC unit. If you want to introduce more air ventilation and pressurization you can open the damper up or install a larger infiltration duct. Call us for more information on this application.

Pressurization Diagram