Frequently Asked Questions - Whispair Rangehoods
What is the warranty of a Whispair rangehood?
Whispair offer a market leading 5-year warranty on all retail hood models. Whispair also offers a 10-year factory endurance warranty on it's 'KleenAir' remote motor systems.
Where are Whispair hoods manufactured?
All Whispair hoods are designed and assembled in our factory in Carrum Downs located in south-east Victoria, Australia. Whispair collaborates closely with several component suppliers such as EBM-papst in Germany to produce its innovative fan motor technology.
What is a Whispair rangehood made from?
Whispair indoor rangehoods are made from the highest quality AISI304 Stainless Steel, whilst the alfresco (BBQ) range is made from the 'marine grade' AISI316 grade stainless steel.
What is the purpose of a rangehood?
The primary aim of a rangehood is to extract cooking by-products from the kitchen environment. Cooking by-products include heat, steam, grease and odour.
Why are Whispair BBQ rangehoods different to most others?

Whispair is one of the few brands that offer an Alfresco (BBQ) rangehood that incorporates AISI316 'marine grade' stainless steel. This is important as the composition of AISI316 stainless steel is more robust and can withstand harsher conditions that would be experienced in an ‘outside’ environment, particularly in coastal areas.

Whispair BBQ hoods are also much deeper than a 'normal' indoor hood. This additional coverage assists with the processing of additional by-product generated by the BBQ cooking process.

Why do rangehoods have filters?
Whilst cooking by-products such as heat and odour need to be extracted from the kitchen environment and expelled into the atmosphere, some by-products such as steam and grease need to be filtered from the air prior to entering the fan motor and ducting. This assists in stopping a build-up of fat deposits which can affect the operation of the fan motor. Filters are positioned at the entry point of most rangehoods to facilitate this process.
Can I use a Whispair rangehood above an induction cooktop?

Absolutely. As all Whispair hoods use thick commercial grade baffle filters, by-products such as grease and moisture are 'stored' in the vanes of the filters, eliminating dripping of any excessive condensate on to the cooking surface.

The build-up of excessive levels of condensate in a mesh filter can lead to dripping of fats and oils back on to the cooking surface and into food.

How does a filter work?
Most filters, whether they are commonly used mesh filters or premium baffle filters, operate on the same basic philosophy. When the cooking surface is in operation, cooking by-products are produced. Most of the by-products are created as a consequence of heat and as hot air rises, the bi-products are carried up to the rangehood. This is also why the most effective rangehoods are designed to be positioned above the cooking surface. When the by-products reach the rangehood, they are sucked into the filtration zone. The heavier ‘dirty’ particles contact the filter surface and condensate, whilst the ‘cleaner’ lighter particles are able to pass through the filters and are exhausted through the ducting.
What is a baffle filter and how does it work?

Baffle filters are commonly found in high quality commercial kitchens, not only due to their superior extraction and filtration performance but because they offer a protective guard preventing flames from the cooking surface passing up into the ducting. They also offer a catchment area within the filters that enables the filter to operate between cleans without loss of extraction or filtration. Baffle filters are formed by a series of interlocking ‘blades’ or ‘vanes’.

These vanes are setup so that one sits inside the other so that when the air is pulled through the filters, the air flow is forced to pass in an ‘S’ pattern. This ‘S’ pattern forces the heavier dirty particles to contact the top surface of the vanes, whilst the finer particles are captured on the inner return surface. This contact causes condensation and the particles rest on the vane surface. The uniform ‘S’ pattern means the vanes are evenly spaced apart creating a clean and consistent path for the air to pass through ensuring that the baffle generates less turbulence than the ‘random’ paths generated by the mesh filter.

As the baffle filter ‘fills’ with grease and moisture, the available surface area on the upper vane surface decreases, this then leads to the condensate dripping into the lower vane, where the surplus by-products are stored without affecting or blocking the air flow. As most baffle filters are made from a solid stainless steel construction, the ease of cleaning is noteworthy. The filters can be easily soaked or placed in the dishwasher and are restored to new without deterioration.

How does a mesh filter work and when should it be used?

Mesh filters are commonly found in most domestic rangehood units due to their low production cost and their ability to effectively filter air in hoods achieving low extraction levels. Mesh filters use random layers of mesh (between 3 to 6 layers) placed one on top of the other so that when the air is pulled through the filters, the air flow is disturbed forcing the heavier dirty particles to contact the mesh fibres. This contact causes condensation and the particles sit on the mesh fibre surface, this process is commonly called ‘absorption’.

Naturally as the mesh filter ‘fills’ with grease and moisture, the available surface area on mesh fibre decreases, meaning that the user will notice a reduction filtration performance between cleans. Additionally, it is also important to note that as the mesh filter fills, the captured by-products are retained with in the mesh, impeding the path for the air to pass through the filter.

The more by-products retained in the filter, the more the air path is effectively blocked, this added resistance not only reduces extraction performance but pressurises the fan motor which leads to additional wear-and-tear on the unit. It is commonly recognised that high performing hoods, that are required to deliver high extractions levels, don’t use mesh filters.

As high performing hoods are generally placed above high performing cooking surfaces that generate significantly more by-products, the drop off in extraction and filtration performance will mean that the hood is not as effective as required. The build-up of excessive levels of condensate in a mesh filter can also lead to dripping of fats and oils back on to the cooking surface and into food.

The ease of cleaning the filters should also be considered. Even “high quality stainless steel” mesh filters will incorporate several layers of aluminium mesh. Aluminium has a thin oxide layer but even with this layer it still venerable to react to hot water during the washing process. This reaction can lead to a reduction and distortion of the aluminium layers. This breakdown will limit the filters long term ability to ‘absorb’ grease and oil.

Which filter is louder - baffle or mesh?

Noise is also an important consideration for many users. When comparing noise levels between filters, the basic rule is, the more air being processed through a filter, the more air noise will be generated. In a like-for-like comparison where the same extraction levels are delivered, baffle filters will generate less noise due to the uniform ‘S’ pattern that the air adopts as it moves through the vanes.

Mesh filters severely disturb the air with the random path created by the layers of mesh creating more turbulence and noise. In a practical sense, the disruption to the air flow in a mesh filter creates turbulence and a reduction in the extraction level. Additionally, if a filter is blocked with by-products then this will also severely reduce the air flow.

That is why all Whispair rangehoods utilise 25mm thick S-FlowTM baffle filters exclusively in Australia and New Zealand.

Important notes about installing your ducting..

When installing the flexi ducting between rangehood outlet and motor, is required to be pulled tight maintaining its 200mm diameter. If ducting remains loose the extraction performance will drop and extra noise will be generated.

What ducting length is recommended?

To get the best extraction performance we recommend that the ducting distance between rangehood and remote motor be 3 metres. We also recommend that if the remote external roof motor is installed directly above the rangehood that a slight bend be installed in the ducting, this will reduce the potential exposure of noise from the motor coming back down the ducting keeping the noise generated from the entire system as quiet as possible.

If your ducting length is shorter than 3 metres, your overall extraction levels will increase but will increase the amount of air movement and associated noise at the filters.

What is the longest I can run my ducting?

It is recommended that ducting not exceed 5 to 6 meters in length. An additional inline motor or a higher capacity motor can be installed in longer duct runs to assist with achieving a desirable performance level. It is important to note that the longer the duct run, the greater the system pressure. The increase in system pressure will reduce the extraction performance.

Additionally, in extraction performance terms, every bend in the duct run is equivalent to an extra meter of ducting.


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