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VentZone Central Ventilation (requires flash to view)

Our customers have been asking for a solution like this for years.  It has become a reality with the help of American Aldes Ventilation.  These products have been used for years in commercial settings like hotels and multi-unit condos and apartment buildings.  Now they are available for the average homeowner via our website.

New VentZone systems by American Aldes offers dynamic zone control of ventilation system airflows.  These ultra energy efficient systems eliminate unnecessary ventilation symptomatic of many popular remote fan installations, while increasing airflow when needed most.  Perfectly suited for residential applications - VentZone combines demand controlled zone register terminals (ZRTs) and Ventergy Series super-energy efficient fans to create the most energy efficient and quite central exhaust system available.


  • Single penetration through roof / wall
  • Remote mounted fan = very quiet operation
  • EnergyStar rated fan
  • Ventilation only where/when you need it
  • Continuous low-level ventilation to satisfy ASHRAE 62.2 standard or other mechanical ventilation standards
  • Also available for simple on/off operation with no continuous ventilation


Here's how it works:

The single, multi-port fan has several inlets on board that connect via ductwork to ZRT registers in your bathrooms.  Each register has a motorized damper within that is normally in a closed position.  Each register is connected to a single pole switch in the bathroom (could be a timer, motion sensor, humidity sensor, etc.).  When the switch is flipped in the bathroom where ventilation is needed - the damper in the local register opens and the fan turns on.  ONLY the one bathroom gets ventilated.  If the other bathroom is in use and a switch is flipped there - then the damper on the register in that bathroom opens as well and that bathroom gets ventilated.  This can be expanded to additional bathrooms - still using the one fan (if intake ports are added to the fan). 

In Figure 1 below - a 3-port inline fan is ducted to 3 different bathrooms, each with it's own dampered ZRT register.   Through the use of an integral damper end-switch, the ZRT triggers the remote fan to start when a switch is flipped in any of the 3 bathrooms.  The switch in the affected bathroom also opens the damper on it's local ZRT.  The configuration in Figure 1 shows the most basic zoned ventilation - without any continous ventilation happening.  It shows simple on/off functionality from each bathroom.  We will include more information about balancing this system at the end of this article.

We sell several kits from Aldes that include fans and ZRTs.  These kits are designed for 2 bathrooms but can be easily expanded by adding additional ports on the fan and additional ZRTs.

For basic zoned ventiation with on/off control for 2 bathrooms (expandable to 4 bathrooms total) choose the VZ-S2 kit.  To upgrade to an IAQ, continuous ventilation solution, choose the VZ-IAQ-P2 kit.  Both kits come with a multi-port fan, a large (6") ZRT for a master bath and a smaller (4") ZRT for a smaller bathroom.  Both kits are expandable to serve additional rooms by adding inlet ports to the fan and additional ZRTs.



Figure 2 below shows a similar configuration to the above, but with a continuous ventilation component.  It is believed that constant ventilation at a low rate is more effective than intermittent ventilation at high rates.  With the setup below - the central fan is always on - drawing small amounts of air at all times from all 3 bathrooms through an adjustable minimum airflow regulator in each ZRT.  When a bathroom  shower or toilet is in use, and a boost of ventilation is needed locally - the switch in the bathroom opens up the damper on the local ZRT.    Just like Figure 1 - a flip of the local switch in any of the 3 bathrooms opens the main damper on the local ZRT for a boost of high-CFM ventilation.



Figure 3 below illustrates the real difference between the two systems.  The ZRTs in the continous ventilation systems feature a minimum airflow regulator built into the damper which allows a small amount of air to leak through.  This regulator can be adjusted to allow 10, 20, or 30 CFM to flow through continously.  The basic system has no regulator in the damper.  The ZRTs are simply open, or closed - depending on the position of the local switch, timer, etc. in the bathroom.




Balancing airflow in a continous ventilation system:

With a central ventilation system, it is important to provide the correct amount of ventilation for each space.  American Aldes has developed a unique product that insures that a controlled and constant amount of air is being pulled from a space.  This product is called a Constant Air Regulator, or CAR.  The CAR is a modulating orifice that automatically regulates airflows in duct systems to constant levels.  The passive control element responds to duct pressure, and requires no electric or pneumatic sensors or controls.  The CAR assembly is sized to fit inside standard rigid round ducting, as well as fittings such as takeoffs, tees, etc. A lip or flex-type ring seal gasket around the circumference ensures a tight, no-leak fit.  One CAR can be easily adjusted to allow different amounts of airflow by removing integral "aero clips" from the regulator.  They simply snap out of the assembly!

Figure 4 below shows an installed CAR in a rigid duct and an uninstalled CAR.  These CARs and be adjusted to allow 3 different levels of airflow, just by removing the clips shown on the top of the assemblies.  Removing or adding clips simply expands or constricts the amount of free air that flows through the device.  Additionally, the flow regulator on the bottom of the CAR does the same thing by rising and falling in response to changes in static pressure in the duct run.

Bottom line - lengthy balancing exercises with butterfly dampers are eliminated by using CARs.  They can be added to the packages above and inserted into the "neck" of the ZRTs to provide just the right amount of airflow.