Cooker Hoods - Advice and suggestions

  • Thread starter NotSureAboutDIY
  • Start date
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NotSureAboutDIY

I see a lot of kitchens with chimney cooker hoods these days, most are re circulating air.
has anyone had experience with fitting these types of hoods?
can you give me advice on how well they work without proper forced ventilation (seems silly to have a chimney design if you chuck the air out the side)

does anyone know the issues of venting these things (probably a 125mm hole in the external wall required) my hood's chimney would be approximately 1150mm from the interior of an external cavity (breeze block then brick) wall.
there is an air brick at around the correct height but Im not sure fitting the hose through this would be a great idea (as it may lose the standard/non forced ventilation my kitchen currently has)

would a second hole above the air brick be a mistake?

does the ducting usually run above ceiling/under first floor or is it OK to chuck it over the top of the wall unit next to the hood.

cheers in advance.
 
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Most hoods can be set either to recirculate the air or vent outside at the time of installation. There are pros and cons to both methods, but the electrical installation will be the same for either method.

Recirculating is easier to install as there is no need to make a hole in your wall and/or run ductwork. However, you will have to be disciplined to change a filter regularly depending on how often and what you cook. The air laden with cooking smells passes through the filter, which usually made from activated charcoal and the smells are removed (in theory, as the filters are not 100% efficient) the filters are easy to replace, but not usually cheap and their efficiency tails off as they are used. It also means you will not be removing the air from the room, so you will not be loosing your heated air. Good in winter, bad in summer. This is usually the DIY method of installation because its easier.

Outside venting gets rid of the air and heat to outside giving far better ventilation and you will not need the activated charcoal filter. This is usually seen as the "professional" method of installation unless it's impractical to run ducting. Long lengths of ductwork (especially the rectangular crossectional type designed to lie flat on the top of cupboards) will also reduce the effectiveness of the fan.

Both types of hood need a grease filter of some sort to stop grease clogging up the fan. Some need to be replaced others are washable.

I would go for outside venting if at all possible.

There are several types of duct available most are 100mm diameter but rectangular duct and various adaptors are readily available. It all depends on the chimney and the route you wish to take.

Hope this helps
 
stem said:
Most hoods can be set either to recirculate the air or vent outside at the time of installation. There are pros and cons to both methods, but the electrical installation will be the same for either method.

Recirculating is easier to install as there is no need to make a hole in your wall and/or run ductwork. However, you will have to be disciplined to change a filter regularly depending on how often and what you cook. The air laden with cooking smells passes through the filter, which usually made from activated charcoal and the smells are removed (in theory, as the filters are not 100% efficient) the filters are easy to replace, but not usually cheap and their efficiency tails off as they are used. It also means you will not be removing the air from the room, so you will not be loosing your heated air. Good in winter, bad in summer. This is usually the DIY method of installation because its easier.

Outside venting gets rid of the air and heat to outside giving far better ventilation and you will not need the activated charcoal filter. This is usually seen as the "professional" method of installation unless it's impractical to run ducting. Long lengths of ductwork (especially the rectangular crossectional type designed to lie flat on the top of cupboards) will also reduce the effectiveness of the fan.

Both types of hood need a grease filter of some sort to stop grease clogging up the fan. Some need to be replaced others are washable.

I would go for outside venting if at all possible.

Hope this helps
was very helpful, my instinct is that ducted extraction is likely to be better.

you mention sqaure ducting, is that a requirement?
and punching holes in walls, any suggestions/tools.

thanks again...
 
Flat duct is approx 200mm wide x 60mm high it's not a requirement but is designed to be laid on the top of wall units so that it can't be seen. Adaptors are available to allow it to connect to a circular outlet.

see here:

http://www.screwfix.com/app/sfd/cat/cat.jsp?cId=100139&ts=53073

You can hire a "core drill" that will make the hole you require, otherwise series of smaller holes can be drilled and then chiselled through. You have to be careful and take your time doing this and it's neater if you can drill in from both sides of the wall, although you will have to measure carefully to make sure you line up.

When you extract air from a room with a fan, air must come in from somewhere to replace it. usually around door frames, airbricks, chimneys etc., If you vent the chimney close to an existing air brick, you might draw some of the air you want to get rid of back in to the room.
 
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stem said:
Flat duct is approx 200mm wide x 60mm high it's not a requirement but is designed to be laid on the top of wall units so that it can't be seen. Adaptors are available to allow it to connect to a circular outlet.

see here:

http://www.screwfix.com/app/sfd/cat/cat.jsp?cId=100139&ts=53073

You can hire a "core drill" that will make the hole you require, otherwise series of smaller holes can be drilled and then chiselled through. You have to be careful and take your time doing this and it's neater if you can drill in from both sides of the wall, although you will have to measure carefully to make sure you line up.

When you extract air from a room with a fan, air must come in from somewhere to replace it. usually around door frames, airbricks, chimneys etc., If you vent the chimney close to an existing air brick, you might draw some of the air you want to get rid of back in to the room.

Tip top advice, cheers again stem, presumably a turn on the exhaust from the wall near the air brick would be adviseable then.

200 x 60 is small enough to only require the removal of 1 brick in the external wall, is this OK to do from a structural point of view?
would I need a support around the vent in the outer wall or could I just mortar the vent in place?
 
There's no need for any additional support for the hole, just be careful not to loosen the surrounding brickwork when making it. What you suggest sounds OK. Infact the vent you refer to appears to be designed for use with the flat channel as it has the same dimensions. But I've never used it.

I prefer to have the outside vent fitted with some sort of cowl or flaps to stop air being blown in from outside when the chimney is switched off. (unless you have a long duct or several bends which will provide some resistance to this effect, or would like the additional ventilation)

Also make sure that the outlet through the wall slopes downward slightly towards the outside so that any rain that might get in runs outside not along the duct and back into the house or chimney.

Sorry for the delay, but like you, I have DIY to do and so am not on line permanently I also have to work, eat, sleep, spend time with my wife and I'm going on holiday tomorrow. :D
 

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