Home |
Search |
Today's Posts |
|
UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions. |
Reply |
|
LinkBack | Thread Tools | Display Modes |
#1
|
|||
|
|||
Cooker hoods: how to vent or not to vent?
Hi
After much conflicting advice from a number of people I thought I'd go after some more from you all I need to install a cooker hood. The purpose of this is to: 1) Remove smoke/steam etc from the kitchen 2) Ventilate the kitchen: kitchen/diner gets too hot when/after cooking. The hood will sit a fair distance (about 3m vert+horiz) from the outside wall, but directly on the (as yet unchecked) wall in front of the chimney flue. The comments I have had are 1) There is no point in having 3m venting as it just doesn't work and is ugly. Should just do recirculating with carbon filter. 2) Recirculating no good at reducing heat. Should either vent or recirculate plus add a separate fan in the kitchen. 3) Separate fan doesn't work well as it doesn't extract from where the heat/smoke is produced. Should vent. Consider adding additional fan in vent to increase power. 4) Adding additional fan problematic as cannot control from hood. 5) Throughput with recirculation less than with venting due to filter obstruction. In addition I was wondering if there is any point in venting to the chimney flue. Possible plus is the there may be a little draw from the chimney (even without a fire), and it would be a lot more attractive. Possible -ve is that smoke would just fall back down the chimney or vent would not cope, so it would be pointless. I would really appreciate any helpful comments anyone has on these options, especially if any of the arguments are fallacious. Thanks in advance. Amos |
#2
|
|||
|
|||
Amos wrote:
I need to install a cooker hood. The purpose of this is to: 1) Remove smoke/steam etc from the kitchen 2) Ventilate the kitchen: kitchen/diner gets too hot when/after cooking. Recirculating will achieve neither. It will reduce smells to some degree, but that's all. All the heat, and more importantly the water vapour, stay in the kitchen. The hood will sit a fair distance (about 3m vert+horiz) from the outside wall This is not very far. Our vent has a total run of 2.5m and works great. 1) There is no point in having 3m venting as it just doesn't work and is ugly. Should just do recirculating with carbon filter. 2) Recirculating no good at reducing heat. Should either vent or recirculate plus add a separate fan in the kitchen. 3) Separate fan doesn't work well as it doesn't extract from where the heat/smoke is produced. Should vent. Consider adding additional fan in vent to increase power. 4) Adding additional fan problematic as cannot control from hood. 5) Throughput with recirculation less than with venting due to filter obstruction. IMO recirculating hoods are only just very slightly better than nothing. Venting is far, far better. The quality of the hood makes a huge difference to how well it extracts. We bought a twin fan hood from Elica, which works much, much better than our old Baumatic hood used to. I'd recommend using a venting hood, and installing the biggest diameter duct you can. 5" is much better than 4". In addition I was wondering if there is any point in venting to the chimney flue. Possible plus is the there may be a little draw from the chimney (even without a fire), and it would be a lot more attractive. Possible -ve is that smoke would just fall back down the chimney or vent would not cope, so it would be pointless. I wouldn't consider that as an option - too many variables, and unlikely to work. -- Grunff |
#3
|
|||
|
|||
On Sun, 19 Jun 2005 17:14:33 +0100,it is alleged that Grunff
spake thusly in uk.d-i-y: In addition I was wondering if there is any point in venting to the chimney flue. Possible plus is the there may be a little draw from the chimney (even without a fire), and it would be a lot more attractive. Possible -ve is that smoke would just fall back down the chimney or vent would not cope, so it would be pointless. I wouldn't consider that as an option - too many variables, and unlikely to work. Just to add to that, there is the fact that all hoods, even filtered ones will expel some grease and lots of moisture in the exhaust. Having that building up in a chimney over time is likely to be very bad odour wise and health wise, and may even cause condensation problems, so that's a definite no. I would definitely go with vented. MUCH better than a recirc.:-) -- "Anyone who is capable of getting themselves made President should on *no* account be allowed to do the job." - The Hitchhiker's Guide to the Galaxy |
#4
|
|||
|
|||
On Sun, 19 Jun 2005 15:46:45 GMT, Amos
wrote: Hi After much conflicting advice from a number of people I thought I'd go after some more from you all I need to install a cooker hood. The purpose of this is to: 1) Remove smoke/steam etc from the kitchen 2) Ventilate the kitchen: kitchen/diner gets too hot when/after cooking. The hood will sit a fair distance (about 3m vert+horiz) from the outside wall, but directly on the (as yet unchecked) wall in front of the chimney flue. The comments I have had are 1) There is no point in having 3m venting as it just doesn't work and is ugly. Should just do recirculating with carbon filter. Ugly is a matter of opinion, and how well you do the vent pipe 2) Recirculating no good at reducing heat. Should either vent or recirculate plus add a separate fan in the kitchen. Recirculating will make the room wharmer, as you have the heat from the fan to add in 3) Separate fan doesn't work well as it doesn't extract from where the heat/smoke is produced. Should vent. Consider adding additional fan in vent to increase power. I think these fans look really ugly 4) Adding additional fan problematic as cannot control from hood. 5) Throughput with recirculation less than with venting due to filter obstruction. Debatable In addition I was wondering if there is any point in venting to the chimney flue. Possible plus is the there may be a little draw from the chimney (even without a fire), and it would be a lot more attractive. Possible -ve is that smoke would just fall back down the chimney or vent would not cope, so it would be pointless. You could run the vent pipe right up the chinmey to the pot, but its hard work ... I would really appreciate any helpful comments anyone has on these options, especially if any of the arguments are fallacious. Thanks in advance. Amos |
#5
|
|||
|
|||
On Sun, 19 Jun 2005 17:14:33 +0100, Grunff wrote:
The quality of the hood makes a huge difference to how well it extracts. We bought a twin fan hood from Elica, which works much, much better than our old Baumatic hood used to. I'd recommend using a venting hood, and installing the biggest diameter duct you can. 5" is much better than 4". Agreed. Take a look at a fairly powerful blower and 120mm or 150mm duct for this kind of length. Try to avoid sharp corners in the ducting by using the flexible type if possible. Take a look at Elica, an Italian manufacturer. Elica make their own branded products plus virtually all for other vendors in Europe on a private label basis. Their UK distributor is DR Cooker Hoods http://www.elica.co.uk/ This site is useful for the catalogue. DR don't supply directly but through resellers such as TLC Electrical and others. It's worth shopping around for best price. I fitted one of their Built-in 80 Ultra models a couple of years ago and it's excellent. It's well worth getting the kind with metal mesh grease filters because these can simply be taken out and washed. -- ..andy To email, substitute .nospam with .gl The information contained in this post is copyright the poster, and specifically may not be published in, or used by http://www.diybanter.com |
#6
|
|||
|
|||
In article , Rick
writes On Sun, 19 Jun 2005 15:46:45 GMT, Amos wrote: In addition I was wondering if there is any point in venting to the chimney flue. Possible plus is the there may be a little draw from the chimney (even without a fire), and it would be a lot more attractive. Possible -ve is that smoke would just fall back down the chimney or vent would not cope, so it would be pointless. You could run the vent pipe right up the chinmey to the pot, but its hard work ... That would be my choice, using a flexible stainless steel flue liner and a vent cap on top. 5" for a 2 storey or 6" for a town house, expect to pay 8-10quid a metre but worth it I think. -- fred |
#7
|
|||
|
|||
"Amos" wrote in message k... Hi After much conflicting advice from a number of people I thought I'd go after some more from you all I need to install a cooker hood. The purpose of this is to: 1) Remove smoke/steam etc from the kitchen 2) Ventilate the kitchen: kitchen/diner gets too hot when/after cooking. The hood will sit a fair distance (about 3m vert+horiz) from the outside wall, but directly on the (as yet unchecked) wall in front of the chimney flue. The comments I have had are 1) There is no point in having 3m venting as it just doesn't work How do you know it doesn't work? Mary |
#8
|
|||
|
|||
On Sun, 19 Jun 2005 20:02:01 +0100,it is alleged that "Mary Fisher"
spake thusly in uk.d-i-y: The comments I have had are 1) There is no point in having 3m venting as it just doesn't work How do you know it doesn't work? I read this as meaning this is an opinion from someone else, and we're being asked our opinion on this opinion :-) Mary -- There are three things which I consider excellent advice. First, don't smoke to excess. Second, don't drink to excess. Third, don't marry to excess. - Mark Twain |
#9
|
|||
|
|||
"Chip" wrote in message n.net... On Sun, 19 Jun 2005 20:02:01 +0100,it is alleged that "Mary Fisher" spake thusly in uk.d-i-y: The comments I have had are 1) There is no point in having 3m venting as it just doesn't work How do you know it doesn't work? I read this as meaning this is an opinion from someone else, and we're being asked our opinion on this opinion :-) Oh ... I THINK I know what you mean :-) Mary Mary -- There are three things which I consider excellent advice. First, don't smoke to excess. Second, don't drink to excess. Third, don't marry to excess. - Mark Twain |
#10
|
|||
|
|||
Chip wrote: On Sun, 19 Jun 2005 17:14:33 +0100,it is alleged that Grunff spake thusly in uk.d-i-y: In addition I was wondering if there is any point in venting to the chimney flue. Possible plus is the there may be a little draw from the chimney (even without a fire), and it would be a lot more attractive. Possible -ve is that smoke would just fall back down the chimney or vent would not cope, so it would be pointless. I wouldn't consider that as an option - too many variables, and unlikely to work. Just to add to that, there is the fact that all hoods, even filtered ones will expel some grease and lots of moisture in the exhaust. Having that building up in a chimney over time is likely to be very bad odour wise and health wise, and may even cause condensation problems, so that's a definite no. Good point. Mice are enough of a problem in Edinburgh flats already? I would definitely go with vented. MUCH better than a recirc.:-) That was my feeling, so I was a little put out when I was told it wouldn't be effective. However I am glad to hear that everyone is pretty much consistent on this Thanks Amos |
#11
|
|||
|
|||
Grunff wrote: snip The quality of the hood makes a huge difference to how well it extracts. We bought a twin fan hood from Elica, which works much, much better than our old Baumatic hood used to. Thanks for all your comments. The twin fan hood - do you mean one with an additional external motor. I'd recommend using a venting hood, and installing the biggest diameter duct you can. 5" is much better than 4". Elica seem to have quite a few 6" hoods. I'll probably go for that. It is a kitchen diner, so it really needs to be kept clear. Thanks Amos |
#12
|
|||
|
|||
Amos wrote:
Thanks for all your comments. The twin fan hood - do you mean one with an additional external motor. You're welcome. By twin fan, I mean one with two motors/fans within the housing, like the Concorde Twin http://www.elica.co.uk/master.asp?http://www.elica.co.uk/view_products_parent.asp?Freestanding%20Hoods Elica seem to have quite a few 6" hoods. I'll probably go for that. It is a kitchen diner, so it really needs to be kept clear. I'd be surprised if you don't get a good result with a decent hood. -- Grunff |
#13
|
|||
|
|||
I would really appreciate any helpful comments anyone has on these
options, especially if any of the arguments are fallacious. Recirculating doesn't work. At all. You can vent 3m no problem. However, you MUST use a centrifugal fan. An axial fan is not capable of doing it, as single stage axial fans can't produce sufficient compression. Use the largest ducting you can aesthetically fit. Christian. |
#14
|
|||
|
|||
Amos wrote:
Hi After much conflicting advice from a number of people I thought I'd go after some more from you all I need to install a cooker hood. The purpose of this is to: 1) Remove smoke/steam etc from the kitchen 2) Ventilate the kitchen: kitchen/diner gets too hot when/after cooking. The hood will sit a fair distance (about 3m vert+horiz) from the outside wall, but directly on the (as yet unchecked) wall in front of the chimney flue. The comments I have had are 1) There is no point in having 3m venting as it just doesn't work and is ugly. Should just do recirculating with carbon filter. I recently fitted a Baumatic built-in extractor (http://www.tlc-direct.co.uk/Products/BMCAN54SS.html) which works *extremely* well with a 4m ducting run (with a right-angle bend after the first metre) using 6" rigid ducting hidden in the ceiling void. This particular extractor has a free-flow flowrate of 500m3/hr and, having gone through the back pressure figures and fan curves I calculate it now runs at ~400m3/hr. Condensation in the kitchen and cooking smells in the rest of house are now a thing of the past, and for =A3150 (fan+ducting) all-in I couldn't believe the bang-for-buck ratio - and it looks superb to boot. It works so well that after installating it I went through half a box of smoke matches due to sheer admiration of its effectiveness... but then I'm sad like that. Mathew |
#15
|
|||
|
|||
On Mon, 20 Jun 2005 10:24:59 +0100, "Christian McArdle"
wrote: I would really appreciate any helpful comments anyone has on these options, especially if any of the arguments are fallacious. Recirculating doesn't work. At all. You can vent 3m no problem. However, you MUST use a centrifugal fan. An axial fan is not capable of doing it, as single stage axial fans can't produce sufficient compression. Use the largest ducting you can aesthetically fit. Also use circular section ducting rather than "space-saving" rectangular section. BES stock a good selection. Mark |
#16
|
|||
|
|||
Also use circular section ducting rather than "space-saving"
rectangular section. BES stock a good selection. And specifically avoid ribbed flexible ducting. Christian. |
#17
|
|||
|
|||
Mark wrote:
"Christian McArdle" wrote: You can vent 3m no problem. However, you MUST use a centrifugal fan. An axial fan is not capable of doing it, as single stage axial fans can't produce sufficient compression. Use the largest ducting you can aesthetically fit. Also use circular section ducting rather than "space-saving" rectangular section. BES stock a good selection. You can also use grey soil pipe and fittings, which are cheaper. |
#18
|
|||
|
|||
Thanks. Actually, my mistake - it is actually 3m horiz + right angle +
another metre and a half, so it is rather long. Even so, in light of comments here, I will vent. thanks Amos Grunff wrote: Amos wrote: Thanks for all your comments. The twin fan hood - do you mean one with an additional external motor. You're welcome. By twin fan, I mean one with two motors/fans within the housing, like the Concorde Twin http://www.elica.co.uk/master.asp?http://www.elica.co.uk/view_products_parent.asp?Freestanding%20Hoods Elica seem to have quite a few 6" hoods. I'll probably go for that. It is a kitchen diner, so it really needs to be kept clear. I'd be surprised if you don't get a good result with a decent hood. |
#19
|
|||
|
|||
Mark wrote: On Mon, 20 Jun 2005 10:24:59 +0100, "Christian McArdle" wrote: I would really appreciate any helpful comments anyone has on these options, especially if any of the arguments are fallacious. Recirculating doesn't work. At all. You can vent 3m no problem. However, you MUST use a centrifugal fan. An axial fan is not capable of doing it, as single stage axial fans can't produce sufficient compression. Use the largest ducting you can aesthetically fit. Also use circular section ducting rather than "space-saving" rectangular section. BES stock a good selection. Call me stupid I could not find any at BES. I plan to use solid duct pipes rather than flexible. Although square makes a bit of a difference, given I cannot go invisible on that one, I might compomise for square. Amos |
#20
|
|||
|
|||
Mark wrote: On Mon, 20 Jun 2005 10:24:59 +0100, "Christian McArdle" wrote: I would really appreciate any helpful comments anyone has on these options, especially if any of the arguments are fallacious. Recirculating doesn't work. At all. You can vent 3m no problem. However, you MUST use a centrifugal fan. An axial fan is not capable of doing it, as single stage axial fans can't produce sufficient compression. Use the largest ducting you can aesthetically fit. Also use circular section ducting rather than "space-saving" rectangular section. BES stock a good selection. Turns out Elica want to charge me 200 quid for the ducting. Ha ha. However I don't really know what I should be paying. Any ideas for 1.5m + 90 degrees + 3m + wall plate of 150mm diameter. I've got it down to 110, but that still seems stupidly high. What should I really be looking for and where. I am clearly missing something. Thanks for any help. Amos |
#21
|
|||
|
|||
On Tue, 21 Jun 2005 13:32:21 +0100, "Christian McArdle"
wrote: Also use circular section ducting rather than "space-saving" rectangular section. BES stock a good selection. And specifically avoid ribbed flexible ducting. Christian. .... but smooth interior is a good choice because you can create much slower bends than are typical for solid ducts. -- ..andy To email, substitute .nospam with .gl The information contained in this post is copyright the poster, and specifically may not be published in, or used by http://www.diybanter.com |
#22
|
|||
|
|||
Amos wrote:
However I don't really know what I should be paying. Any ideas for 1.5m + 90 degrees + 3m + wall plate of 150mm diameter. I've got it down to 110, but that still seems stupidly high. What should I really be looking for and where. I am clearly missing something. I used aluminium duct from BES (125mm). They also do a 150mm. http://www.bes.ltd.uk/products/181.asp -- Grunff |
#23
|
|||
|
|||
On Tue, 21 Jun 2005 20:40:58 GMT, Amos
wrote: Mark wrote: On Mon, 20 Jun 2005 10:24:59 +0100, "Christian McArdle" wrote: I would really appreciate any helpful comments anyone has on these options, especially if any of the arguments are fallacious. Recirculating doesn't work. At all. You can vent 3m no problem. However, you MUST use a centrifugal fan. An axial fan is not capable of doing it, as single stage axial fans can't produce sufficient compression. Use the largest ducting you can aesthetically fit. Also use circular section ducting rather than "space-saving" rectangular section. BES stock a good selection. Call me stupid I could not find any at BES. I plan to use solid duct pipes rather than flexible. Although square makes a bit of a difference, given I cannot go invisible on that one, I might compomise for square. If you select "Installation" on the left hand (index) then "Ventilation" on the pop-up menu and finally "Ventilation, Ducting and Accessories". Skip all the rectangular stuff at the top and the circular ducting starts near the bottom of the page. Hope this helps. Mark. |
#24
|
|||
|
|||
On Tue, 21 Jun 2005 13:32:21 +0100, "Christian McArdle"
wrote: Also use circular section ducting rather than "space-saving" rectangular section. BES stock a good selection. And specifically avoid ribbed flexible ducting. You mean the stuff with a spiral wound wire? I use this and it seems OK (it's well stretched out though). Mark. |
#25
|
|||
|
|||
I use this and it seems OK (it's well stretched out
though). It absolutely trashes the airflow, though. Christian. |
#26
|
|||
|
|||
Amos wrote:
Also use circular section ducting rather than "space-saving" rectangular section. BES stock a good selection. Turns out Elica want to charge me 200 quid for the ducting. Ha ha. However I don't really know what I should be paying. Any ideas for 1.5m + 90 degrees + 3m + wall plate of 150mm diameter. I've got it down to 110, but that still seems stupidly high. What should I really be looking for and where. I am clearly missing something. Thanks for any help. Amos I got all mine from http://www.fansdirect.co.uk/ Their catalogue doesn't cover their entire stock so here're the part numbers and prices (exc. VAT) for my stuff: PVC693WH Connector for 150mm=D8(ID) pipe =A33.40 PVC696WH Pipe Fastener to suit 150mm=D8 pipe =A32.20 PVC690WH 90=B0 bend (PVC) to suit 150mm=D8(ID) pipe =A312.00 PVC1200-6WH 150mm=D8 rigid PVC pipe, 2m length =A310.50 Free delivery for orders =A310. (Note: 90=B0 bend looks quite pricey so I may have bought that elsewhere.. BES?) I bought the outlet plate (gravity flaps) from Screwfix (http://www.screwfix.com/app/sfd/cat/...523&ts=3D43615) - at the time of purchase it didn't feature in the paper catalogues.. this may have changed now. I did quite a bit of searching round to get the best prices - admittedly this search was limited to the Internet (me being a lazy arse and all) and the local sheds. You might be able to pick up something cheaper from the 'specialists'. Mathew P=2ES. Incidentaly, looking at both the BES and FansDirect product codes it would appear that it's pretty much all manufactured by Domus (http://www.domusventilation.com/index2.htm) whose catalogue is well worth downloaded for the item lists/descriptions and back pressure figures. |
#27
|
|||
|
|||
Thank you very much.
Amos Mark wrote: On Tue, 21 Jun 2005 20:40:58 GMT, Amos wrote: Mark wrote: On Mon, 20 Jun 2005 10:24:59 +0100, "Christian McArdle" wrote: I would really appreciate any helpful comments anyone has on these options, especially if any of the arguments are fallacious. Recirculating doesn't work. At all. You can vent 3m no problem. However, you MUST use a centrifugal fan. An axial fan is not capable of doing it, as single stage axial fans can't produce sufficient compression. Use the largest ducting you can aesthetically fit. Also use circular section ducting rather than "space-saving" rectangular section. BES stock a good selection. Call me stupid I could not find any at BES. I plan to use solid duct pipes rather than flexible. Although square makes a bit of a difference, given I cannot go invisible on that one, I might compomise for square. If you select "Installation" on the left hand (index) then "Ventilation" on the pop-up menu and finally "Ventilation, Ducting and Accessories". Skip all the rectangular stuff at the top and the circular ducting starts near the bottom of the page. Hope this helps. Mark. |
#28
|
|||
|
|||
Mathew J. Newton wrote:
I got all mine from http://www.fansdirect.co.uk/ Their catalogue doesn't cover their entire stock so here're the part numbers and prices (exc. VAT) for my stuff: PVC693WH Connector for 150mm=D8(ID) pipe =A33.40 PVC696WH Pipe Fastener to suit 150mm=D8 pipe =A32.20 PVC690WH 90=B0 bend (PVC) to suit 150mm=D8(ID) pipe =A312.00 PVC1200-6WH 150mm=D8 rigid PVC pipe, 2m length =A310.50 Free delivery for orders =A310. (Note: 90=B0 bend looks quite pricey so I may have bought that elsewhere.. BES?) Oops - just realised I posted a load of symbols which may not come out correctly in everyone's newsreader. Any '=3DA3' is a pound sign, thus the 2m pipe us GBP10.50 etc. Sorry if this causes confusion... Mathew |
#29
|
|||
|
|||
On Wed, 22 Jun 2005 10:57:14 +0100, "Christian McArdle"
wrote: I use this and it seems OK (it's well stretched out though). It absolutely trashes the airflow, though. Is it any worse than a 90 degree bend though? What would be a better alternative? Mark. |
#30
|
|||
|
|||
It absolutely trashes the airflow, though.
Is it any worse than a 90 degree bend though? What would be a better alternative? You can get types with a smooth internal bore. The cheaper ribbed types cause turbulence in the flow, dramatically increasing resistance. Christian. |
#31
|
|||
|
|||
On Thu, 23 Jun 2005 09:30:12 +0100, "Christian McArdle"
wrote: It absolutely trashes the airflow, though. Is it any worse than a 90 degree bend though? What would be a better alternative? You can get types with a smooth internal bore. The cheaper ribbed types cause turbulence in the flow, dramatically increasing resistance. I haven't seen any like this. Are there any national/online suppliers? Mark |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Cooker hoods and charcoal filters | UK diy | |||
Cooker extractor Hoods and kitchen ventilation? | UK diy | |||
Flat or slim cooker hoods | UK diy | |||
Electrical - Rangemaster p90 all gas | UK diy | |||
Cooker Hoods | UK diy |