SANCTUARY AIR

whole home air purifiers are quiet, ozone-free and energy efficient,

giving you economical

24/7 operation. 

SANCTUARYAIR

purely for your health

Phone 03 8560 2111

Manufacturer of premium quality central air purifiers

Disclaimer    Copyright © Sanctuary Air Victoria 2015

The effectiveness of an air-cleaning device in removing pollutants from an occupied space depends on three  primary factors: 1) the filter's particle removal efficiency, 2) the air flow rate passing through the filter, usually expressed as cubic meters per hour; and 3) the air flow pattern, i.e.  the path that the clean air follows after it leaves the filter.

The effectiveness of an air-cleaning device can also be affected by

1) whether the purifier can be operated economically   24/7, because re-contamination is continuous, as is your breathing. 2) The noise level should not prevent people from spending time in the purified zone, 3) whether pure air can be distributed to all frequently occupied spaces within the premises at the same time.

​The following table explains some of Key Performance Indicators of three types of air-cleaning devices/systems using HEPA filters:

An air purifier competes against continuous re-contamination occurring within the space. 

The effectiveness of an air-cleaning device is a measure of its ability to reduce airborne particle or gaseous pollutant concentrations in an occupied space.​​​​ AHAM recommends an effectiveness of 80% as a meaningful indicator, which is consistent with Australian Standard AS 1668.2-2002 (Part 2, Ventilation design for indoor air contamination control).  For example, a purifier with a coverage specification of 20 sq.meter, indicates that the device can achieve 80% effective reduction in steady particle concentrations in an indoor space of 20 sq.meter.

On the other hand, a filter's particle removal efficiency is usually expressed as a percentage of  pollutants removed from the air that passes through it. For example, a filter may remove 99% of the particles from the air that passes through it (i.e., have 99% efficiency). However, if the airflow rate through the filter is only 15 cubic meters per hour (cmh) in a typical room of approximately 29 cubic meters (e.g., 4 x 3 x 2.4), the filter will be relatively ineffective at removing particles from the air (i.e., 10 times less effective than if the airflow rate were 150 cmh).

A filter rating of 99.97% efficiency DOES NOT translate directly to 99.97% effectiveness of a purifier.

NOTE [1]AIR FLOW RATE AND CLEAN AIR DELIVERY RATE (CADR)

CADR is a voluntary standard developed by the Association of Home Appliance Manufacturers (AHAM), and is recognized by the American National Standards Institute. The standard compares the effectiveness of a brand new portable air cleaners in a room size test chamber, by measuring the CADR for each of three types of particles in indoor air: dust, tobacco smoke, and pollen. For example, an air portable unit that has a CADR of 250 for tobacco smoke can reduce tobacco smoke particle levels to the same concentration as would be achieved by adding 250 cubic feet per minute, equivalent to 425 cubic meters per hour  of clean air. 

Because air flow resistance increases as the filter efficiency rating increases and or filter surface decreases, it is very challenging for a portable unit to achieve high CADR using a genuine HEPA filter of practical size without incurring high energy consumption and/or high noise levels. ​

As this is a voluntary American standard, some Australian and European models may not have a CADR rating.

The CADR testing does not apply to whole-house air-cleaning devices due to a different air flow pattern.

NOTE [2]  AIR FLOW PATTERN

Due to the close proximity between inlet and outlet of a portable unit, a portion of purified air is re-drawn or short-circuited back to the unit  before  mixing sufficiently with the rest of air in the room. In effect, the purifier uses a portion of energy circulating pure air along the air path without purifying air further away.

On the other hand, ducted purification systems have a much more efficient air flow pattern: 

• Pure air is distributed to multiple outlets distant from the inlet, effectively diluting air pollutants concentration in the rooms you intend to purify.
  
• By applying different air flow rates to different outlets, the rooms can be prioritised for pure air delivery.
  
• A higher dilution index (DI) can also be achieved for a priority zoom by closing the door and creating a positive pressure within the closure, effectively preventing air pollution penetration from outside of the zoom.
  

NOTE [3]ENERGY EFFICIENCY

Purifiers installed in the return duct of ducted heating/cooling (HVAC) systems that rely upon the air mover within the existing HVAC system argueably consume no additional power when the HVAC system is operating. However, your HVAC, either be a reverse cycle conditioner or gas ducted heater, operates less than 15% of the time throughout a year. When cooling or heating is not required, it can be very expensive to use the air mover of your HVAC system to operate your air purifier continuously, because these air movers are design to move large volume of air for a short period of time and can consume  500 to 1500 watts. 24/7 air purification is very expensive for HVAC return-duct purifiers.

On the other hand, an independent ducted purification system will have a dedicated air mover that is specifically designed to operate continuously. A well designed independent ducted purification system can achieve the same power consumption of a typical portable unit for the reasons that:

• A ducted system can have a very large HEPA filter without floor space restriction. Air resistance decreases exponentially as filter surface area increases;
  
• A ducted system has a more efficient air flow pattern than a portable unit.
  

An independent ducted purification system can operate 24/7 economically.

What are the Key Performance Indicators of a purifier?

To choose air-cleaning devices,  it is important to understand the difference between efficiency and effectiveness.

Quality Australian Made Ducted Air Purifiers

 SANCTUARYAIR

  Purely for health

 03 8560 2111