Cooker Hoods for the home

An efficient cooker hood above the hob is a must for removing lingering odours and
grease (contained in steam) from the air. A cooker hood (or extractor unit) can be
housed in a unit to match your kitchen décor from classic, traditional, modern to country.

The actual look and design of the cooker hood is essential since your cooker hood will become the centerpiece of your kitchen. At times if you go really cheap it will give the
look of being cheap and then it goes the other way too.

Extraction or recirculation?
 
If you don't have access to an outside wall, you will need a recirculation hood, which passes the air through charcoal and grease filters before returning it to the kitchen. However, they are not as effective as ducting air away to the exterior source, which extraction hoods do.

How to Choose Your New Cooker Hood

One of the key things to consider is style and look. But to ensure your choice gives
optimum performance it should be at least as wide as your oven or hob. Will your choice
be ducted to the outside of the house? If so, the ducting needs to be the right size; a
cooker hood installed with the correct ducting will extract virtually all the steam, cooking odours and airborne grease from the kitchen. If however, it’s impractical to install ducting
in your home, then charcoal filters can be used to re-circulate fresher air around the room.

In order to keep your kitchen clean and clear of steam and cooking odours by using a
cooker hood or extraction unit the extractors should be either an air extraction or air recirculation cooker hood:

Air Extraction - Removes the air from your kitchen, either directly to the outside or
through another room or void via a ducting kit. The main reason for installing an extractor
is to take away the smells and grease that are produced during cooking. Extractors will also help to take away the steam and heat that is associated with cooking on a hob. The ‘dirty’
air passes through a grease filter first, which is normally made up of layers of aluminum mesh (metal grease filters). Some extractors do still use paper grease filters, which can
be washed a few times but will eventually need to be replaced. Metal grease filters can be washed in the sink or a dishwasher, and therefore do not need to be replaced

The airflow power required normally depends on the size of kitchen and type of cooking.

It's important to choose the right size extractor for your hob and your kitchen, and there's
a simple calculation to work this out. Just multiply the volume of your kitchen (length by width by height in metres) by ten (the minimum number of times per hour the extractor
will filter the air) and you will arrive at a figure which gives the minimum extraction rate, expressed as cubic metres per hour (m/h). All manufacturers provide this figure.

Simply multiply the volume of the kitchen by ten and you will obtain the ideal airflow for
that room.

For example, for a kitchen of 3m x 4m with a height of 2.7m: (3 x 4 x 2.7) x 10 = 324, therefore any product with airflow superior to 324 m³/h should give complete and efficient ventilation of the room.

Efficient aspiration of fumes from the cook top also depends on the correct use of the
product and the system of ducting installed.




Air recirculation -- Pulls the air through a
filter and back into your kitchen. Many
range cooker manufacturers offer hoods
in matching styles and colours—just make sure that the hood you select blends in with the décor and visual image you are going
for with your kitchens style.

Steam created by the cooking process can cause unpleasant wet walls and furniture.  It makes the kitchen a less pleasant place to be for both the cook and the family.  In extreme cases mould can form on decorations and kitchen units can be affected so much that doors jam and carcasses bulge as they absorb water.  Wallpaper may peel away and the joints become obvious.


Types of Cooker Hoods

Chimney
Integrated
Canopy
Conventional
Telescopic
Downdraft (For worktop or island installation)
The Free-standing cooker hood—usually supplied with charcoal filter included, is at very competitive prices and are available in 60 and 90cm widths.  These may be single or twin motor.

The Integrated cooker hood—most popular size 60cm, but also available in 90cm
widths.  These models are only used in fitted kitchens.  They are always fitted between
wall units and have a door on the front, which matches the other kitchen furniture and effectively hides the appliance except when viewed from below.  Opening and closing the door switches the fan on and off at the speeds previously set and also activates the cooker
hood lights to illuminate the cooking surface.  Very popular with the kitchen trade and
price is usually included in the basic cost of the kitchen.

Built In and Canopy Hoods—are fitted into the base plate of wooden or metal canopies.  Typically available in both 60 and 80cm widths, with single or twin motors.  These models
are only visible when viewed from below as they are generally fitted into specially made decorative canopies.

Chimney and Island Hoods –are highly visible, high tech models that are used as
features within the kitchen and are usually much more expensive than the other types
of hoods.  These hoods mainly feature halogen or fluorescent lamps and very high performance fan motor systems.  Accessories such as spice racks, utensil rails and
back plates are available to enhance the appearance of these models.

Classic Canopy and Cove designed to enhance range style cookers.

Ducted out or re-circulating?

All extractors are designed to take the ‘dirty’ air through ducting and then out to the
outside world. The majority of extractors also have the facility to have a carbon/charcoal filter fitted, which will get rid of the cooking smells. The ‘cleaned’ air is then blown back
into the kitchen via a vent in the extractor. This does not help alleviate the ‘problem’ of condensation etc. caused by steam, but sometimes is the only option if the extractor is
not fitted to an outside wall.

It is important to keep the ducting ‘run’ as short as possible. Every bend or elbow in the ducting will reduce the efficiency by approximately 5%. Always use the manufacturers recommended ducting, normally 125mm or 150mm diameter. Current building regulations require virtually all hoods fitted within new properties to be ducted out.

Remote motors

Some manufacturers offer extractors with a remote motor. This means that the
motor/fan unit is not situated inside the appliance, but is fitted ‘remotely’. The remote
motor is normally fitted in a loft space or onto an outside wall and is connected to the
‘hood’ by a power cable. Ducting is required to take the ‘dirty air’ from the hood to the
motor and this must be ordered separately. The main advantage of this type of extractor
is that they are a lot quieter than ‘standard’ hoods. The extraction rate is also improved,
and can be up to 25% more efficient.

Installation Requirements

Installation in the re-circulating mode:

Problems are very rare when no ducting is involved, but of course there must be first a paper, fibre or aluminium grease filter, and secondly a charcoal filter.  There must be a
clear gap between these two filters, if not then grease will quickly contaminate the charcoal filter, rendering it useless within a very few weeks.

Grease filters should be cleaned or replaced every
3 or 4 months, and charcoal filters at around 18 months according to the amount of hob cooking time.

Installation in the ducted mode:

Choosing and Installing the Correct Ducting

Because it is normally hidden, a ducting system is often not considered an important part
of the construction or refurbishment of a building. However, the importance of the correct ducting is slowly becoming recognized by the building industry.

It is not always the fault of the cooker hood when dreams of fresh rooms and low noise
fans are not achieved. It can often be that the wrong size ducting or wrong configuration
has been selected by the installer or by the system designer.

Air movement is often made more complicated than it actually is. Air moves just as water moves and it is sometimes useful to visualize a problem by substituting air with water.

In ventilation installations the aim is normally to move the air from its source to the
outside of the house as efficiently and quietly as possible. It is, therefore, common sense that to do this effectively, the shorter the distance the air has to travel, the quicker the
aim is achieved. It is also common sense that if an obstacle is put in the way, such as a bend, the process will become more difficult as the air will lose its momentum and may require more powerful assistance in order to achieve the aim.

Cooker hoods vary in power just as cars do and the results are reflected in much the
same way. A high performance/specification car should be quieter, last longer and
generally provide the driver with more comfortable and satisfactory results. However,
to ensure this, the car needs a straight smooth road on which to travel effectively.

The road for the air to travel when using an extractor fan is the ducting. Again, it is
common sense that a more powerful fan would need a more efficient duct - a Rolls
Royce owner would not consider driving their car in off-road conditions! It is worth remembering that the manufacturer’s guarantees will be invalidated it the correct size
of ducting is not used to match the power of the hood.

A few key installation guidelines can be applied to help ensure that the ducting selection is correct and installed in a way that optimizes the extractor’s performance:

• Choose the shortest and most direct route to the outside or the point where the air is to
be released.
• Ensure that bends are kept to a minimum.
• Check the extraction capability and connection size of the hood and choose an appropriate size duct. Refer to the Model for performance ratings. DO NOT, UNDER ANY CERCUMSTANCES, REDUCE THE DUCTING SIZE. If the hood outlet is 150mm (6”) then the ducting must be of the same area.
• Air travels better through a round duct, as the air will travel at a lower speed, resulting in less turbulence, vibration, and noise and energy loss. However, the installation space available may prevent this ideal.
• A rigid duct is more efficient than a flexible duct and should be used whenever possible.
• If flexible hose is used, the hose should remain taut and as straight as possible.
• Special consideration should also be given to the selection of the wall terminal and the
use of back draft dampers, as these also increase air resistance.

Types of ducting:

Round Pipe Ducting
A round duct provides optimum airflow performance and should be used if installation
space allows. We have a selection of bends and adapters to meet most installation requirements.

Rectangular Ducting (Flat Channel)
Rectangular or flat channel ducting is an excellent alternative when space is restricted.
Its low profile enables the ducting to be easily concealed in the ceiling void or along the
top of wall units. We have a selection of bends and adapters to meet most installation requirements.

Flexible Hose Ducting
Flexible hose is available in round and rectangular form, to complement the rigid systems.
It provides a solution to overcome awkward situations where a rigid system cannot be installed. Flexible hose is most effective for slow moving air, such as with tumble dryers,
but can be used with higher volume appliances (with due care taken to ensure that its use
is limited and that the hose is kept as taut and straight as possible).

As has already been explained, the performance of the fan is dependent on the
performance capability of the hood itself, the size of the duct, the ducting configuration
and the type of wall terminal installed.

Each ducting run can be planned in advance and its performance levels evaluated so it
can be ascertained if the desired installation will meet the required level. Technical data is available for the cooker hood installer or system designer in order to achieve the optimum overall extraction rate.

Cooker Hood problems on new installations:

Before calling a service engineer, check that the electrical supply is plugged in and
switched on, if ducted to the outside of the house, check that; -

Ducting is of the correct diameter if round; or an equivalent area if rectangular.

The ducting is not kinked or pinched anywhere along the whole length.

If there is a back draught shutter installed, at either end of the run, it is properly located
and opens and shuts when the fan is switched on and off.

There is no rubble or even a draught stopper that has been fitted while waiting for the
cooker hood to be installed.

These need an electrical supply within 1 m of the unit, ideally located behind the extract
cowl or behind a kitchen cupboard to hide unsightly cables. It is a legal requirement that
all hoods need to be 760mm between the bottom of the hood and top of the cooker / hob.
Check with a Kitchen Appliance consultant for more specific requirements and help.

What Style
There are various styles of extractor hood as follows:

• Chimney -a feature hood usually fixed to the wall & used over large hobs or
  range cookers. You can also get island chimneys that fix to the ceiling over a
  cooker or hob located within an island so that so it looks good from all sides.
  The chimney section for both is usually height adjustable.
• Integrated - these are built into your kitchen units and are hidden apart from
  when they are in use.
• Conventional - these are fixed to the bottom of a cupboard over the cooker
  / hob and protrude at the front.
• Telescopic - fitted into a kitchen unit with a shallow front cupboard. It fits flush
  when not in use, but extends out from the cupboard when in use.

Features to Consider in Your Cooker Hood.

Essentials
These will be offered to you after you choose to buy any cooker, oven or hob. Please note you will only be offered essentials that are compatible with the product you have bought.

Hob cleaner - This will clean glass and ceramic cooking surfaces without scratching- and is safe to use on cold or warm surfaces.

E-Cloth stainless steel & glass cleaner - Maintain the pristine condition of your new appliance - this cleaner will clean and shine both stainless steel and glass to keep your cooker looking like new.

Spare hood filters - To ensure your hood keeps your kitchen smelling clean and fresh you need to change your cooker hood filter regularly. The length of time will depend on how much cooking you do.
 Splashbacks
A splashback is a separate plate of metal that is designed to fit in between the hob and the cooker hood. They are available in stainless steel or black, and offer a stylish finish to your cooker.

Please note that, unless stated otherwise, the range cookers and hobs typically do not come with hoods or back plates but they are available separately.

There are various colours and finishes available, and there are lots of different ways of describing or identifying them. Brushed steel and stainless steel are the same essentially, although some manufacturers do offer a “Polished steel” finish which is very shiny and will show finger marks etc. Aluminium is a less shiny alternative to Steel and is offered as an alternative to reduce the “finger mark problem”. Aluminium is normally more expensive to purchase.

Manufacturers

Admiral, AEG, Baumatic, Belling, Bosch, Britannia, Cannon, CDA, De Dietrich, Electrolux, Elica, Fagor, Falcon, Fisher Paykel, GE, Hotpoint, Ignis, Indesit, Maytag, Neff, New World, Rangemaster, Siemens, Smeg, Stoves, Tecnik, Whirlpool and Zanussi.