Do I need a Cooker Hood

[Jenka123]

I am hoping to buy a house which has a large kitchen/dining/living room with a vaulted ceiling. The hob is set in an island unit, but there is no cooker hood or other extractor unit. The owner has said that he was told it was unnecessary due to the height of the ceiling/size of the room, but I find this hard to believe. What do other people think?

If I do have to install one, does anyone have any recommendations for one with a very long chimney to get up to the high ceiling? I don't think I could have a downdraft model as it is a new island unit and also presumably we would have to rip up the floor to ventilate out.

If you move the cooker so it is next to an external wall, it will be thousands of pounds simpler.

The owner was not told it was unnecessary. He was told it was very difficult and expensive.

A showroom kitchen in a magazine is not the same as a kitchen that is actually used.

You don't have to have one but, with it being open-plan, advisable to have one.
I'd agree with piglet John and, if possible, move the cooker to an exterior wall. It would be very costly to have one fitted in the middle of the kitchen.

You can install a wall mounted extractor fan on an external wall instead of a cooker hood. if it's a really big room it might need a fairly powerful one.

We've been looking at this because I want our hob to be in an island but don't want an ugly hood ruining the clear line of sight across the room. Also I've never turned on the one we currently have, I use my job mainly for rice/pasta and it just never seems worth it. Most smelly/sauce things go in the slow cooker. So we're going for an extractor fan on an outside wall instead, which I think is ok with building regs (someone please say if not as I'll need to plan in a pop up one in the island otherwise)

if you have a wall fan rather than an extractor hood, it has to be much more powerful, because it is not capturing the fumes and steam at source.

The throughput (in cubic metres per hour) is shown on tables, it may be on the BR section of your council's website.

I haven't got a link, but I have used the calculator, it is dependent on room size, and the power required can be stunningly huge.

@Boobsaclock have you thought about a hood which is flush with the ceiling? Much more £££ but will be more discreet.

well that's funny

it's not as I remember it
www.planningportal.co.uk/info/200130/common_projects/34/kitchens_and_bathrooms/6
says twice the power if not over the hob

convert litres/second to cubic metres/hour
www.convert-me.com/en/convert/flow_rate_volume/liter_s.html

but see also
www.tlc-direct.co.uk/Technical/Ventilation/Ventilation4.html

here are some big suckers

Thanks @pigletjohn that's v useful.

We'll price up different options. It's annoying because realistically I'll just open a door if the room needs airing but obviously don't want to go against regs.

Sorry but I'm surprised at "stunningly huge". A very ordinary wall fan will deliver 60 litres/second which is the Building Regs requirement (well for new houses), that is compared to 30 l/s on a cooker hood. They are way quieter too.

Actually for existing houses nobody will come round and force you to install something, but you are supposed not to remove an extractor that's already there. If you choose to add an extractor those are the numbers as I understand it.

OTOH I'm surprised at what your vendor said - have they had building work done to knock this big room together and did they get a completion certificate from Building Control?

x posted.
Something like one of these depending on how you want to control it. As high up on the wall as possible.

It is actually a barn conversion and as far as I know everything has been done properly. Do Building Regs vary in different areas?

If I have it right, 60 litres per second is 216 cubic metres per hour, which is quite a powerful fan, but not as huge as I thought I remembered. The BRs for kitchens don't refer to room size, I must have been thinking of some other ventilation calculator.

Yes, bigger fans are quieter than small fans, they don't need to spin so fast.

A two-speed fan is handy, so you can run it slow when boiling an egg, and turn it up when making a curry.

I have come to a preference for built-in canopies, or integrated models, rather than hoods.

Over the hob is more efficient than a wall fan, because it snatches away the odours and vapourised fat before they have a chance to impregnate the room.

I would suggest that you check with your solicitor/ conveyancer on the purchase. They will be able to confirm whether the seller has all the requisite planning permissions and the Building Regs completion certificate (which are two different things) for the conversion.

The completion certificate is absolutely definitive and will confirm that the current configuration of the kitchen (e.g. the absence of an extractor) is as per the regs.

You may also want to know that the conversion was carried out in accordance with the permission that was granted, including due confirmation from planning that all conditions in the permission (if any) have been met.

If all is in order, I wouldnt worry about it unless it is important for you to for the space to be ventilated. My understanding from PigletJohn's link to the planning portal is that an extractor is not required unless there are no windows that can be opened in the kitchen/ entire space (which seems unlikely?).

It reads that the "opening window" applies only to WCs. And for fan timed overruns (but not the need for fans) in bathrooms.

It says:

"Any new kitchen, WC with no openable window, bath/shower room or utility room should be provided with a mechanical extract fan to reduce condensation and remove smells. The necessary performance of these extract fans is normally measured in litres per second (l/s) as follows:

•Kitchen - 30l/s if placed over the hob and 60l/s if place elsewhere

•Bath/shower - 15l/s with an additional 15 minute overrun (after the light is switched out) if there is no openable window

•WC - 6l/s with overrun

•Utility room - 30l/s"

Ah, I see what they did there - I misunderstood!

Regardless, I think the conveyancer will be able to give you the comfort you are looking for in respect of whether the lack of an extractor breaches building regs.

You may be able to negotiate a price adjustment for having to get one installed if they did.

It's just a thought - they haven't installed one of those whole house mechanical or passive stack ventilation systems have they? We have a PSV and therefore exempt from kitchen/bathroom extractors because it effectively operates continuously in the background.

I tell you, there's a wonderful world of ventilation out there .

Thank you all so much for your replies. I was worried that I might get condensation running down the windows and black mould on the ceiling! Not to mention cooking smells permeating the whole house.

I have open-plan, and you can expect cooking smells to diffuse throughout the space.

Sucking them away from the hob is the most effective way to limit it.

If you have to suck out the air from the entire ground floor, at, say, 12 air changes per hour (I don't know how these numbers are decided) it will also waste heat, unless you use a heat-exchanging ventilation system.

In a typical kitchen, closing the door and having an extractor that creates slight suction will prevent steam or odours escaping into the rest of the house.

If the kitchen is open to the stairway, they will permeate the house.