cooker hoods

[sm_jamieson]

Choosing a cooker hood for kitchen / diner. Room reasonable size so need fairly good extraction rate and want a quiet fan. So, external fan then ? The market seems to be polarized into cheap cooker hoods (couple hundred quid) with the fan in the unit extracting say 300 metres cubed per hour. Or much more expensive units with separate fans e.g. at 700 quid

one has 1200 cubes per hour so a pretty powerful fan (not easy to find among the fans for bathroom extraction etc). They all look much the same (brushed steel chimney, curved glass at bottom). However, there seems to be rather a price discontinuity between the two types. It struck me you could get a B&Q type cheapy and connect to an external fan and save a few hundred quid. Only thing is rewiring the buttons on the unit to control the remote fan may not be easy. Maybe a fan speed controller could be connected up giving a better result that the few fixed speeds on most hoods. Anyone done something like this, or should I just get the 700 quid job and be done with it ? Needless to say, SWMBOEAC (especially at christmas) says just get the

700 quidder and be done with it. Other thing I need to check is the size of the external fan as I would have to fit it into a fairly small loft space.

Cheers, Simon.

[Tim Watts]

It may or may not be any use to you, but I've been through this thought exercise.

I have a 21m2 room to deal with, but the physical route to fit an extract duct to a hood is hard (not impossible but hard).

I was also concerned about unnecessary heat loss if, say just frying which needs air cleanup but doesn't make much steam.

In the end I've decided to fit a basic recirculating hood - choice based on one that has good filters - particulary grease filters, which must be dishwasher proof.

And a separate extractor fan somewhere more convenient for external vent access. Quite possibly a self contained recovery unit (they seem to claim about 70% heat recovery).

With the heat recovery option, I have the further advantage that the unit is more balanced so less likely to upset the coal fire in the same room - and I can chose whether I really need to chuck air outside or not

- could even put it in a humidistat and leave it to its own devices.

Just some random thoughts...

[Donwill]

Why not remove the fan from the hood and reuse it in a diy housing and ducting in the loft? Don

[tim....]

What are cooker hoods supposed to do

I have never ever turned mine on (in any of 5 houses) and I don't think that my kitchen has suffered for it

tim

[Dave Plowman (News)]

Help remove steam etc and cooking smells?

I use mine all the time. One with heat recovery would be ideal in this weather. ;-)

[sm_jamieson]

Its a point. If you use lids all the time, the room is not filled with steam. Not good if you are trying to reduce a sauce though ! Simon.

[sm_jamieson]

Hum. I do like the sound of that. And we use an electric steamer quite a bit that would be better served with a separate extractor - I was going to fit one by the ceiling anyway for removing hot air in the summer. A heat recovery unit for the whole room would make lots of sense. People do slate the recirculating hood though. How much are the replacement cartridges ? Simon.

[Tim Watts]

I refer the honourable gentleman to the reply I gave earlier regarding the separation of filtering and extraction to two different devices :)

But yes, a combo hood would be a good idea - after all, in this weather, running a cooker flat out for an hour produces quite a lot of heat that would be better left to wander around the house rather than blowing it down a tube outside to keep some cockroaches warm.

Given the size of the "chimneys" over some models, it wouldn't seem hard to incorporate a recovery unit and you could even have the option of a concentric flue - or - a twin duct system for routing convenience depending on the install.

Cheers, Tim

-- Tim Watts

[Tim Watts]

It's the carbon filters that cost. The grease filters, if metal mesh (many are) are effectively free as you wash them (hence the bit about being dishwasher proof - and I've seen models that say they are).

I wonder, if the metal grease filters are sufficiently efficient, whether the carbon filter could either be run to death and left until it starts to reduce airflow or even removed altogther.

Cooking smells are of no interest to me, I don't find them bothersome - I care primarily about getting rid of the grease before it fouls everything, and secondly, getting rid of excessive steam. Cheers, Tim

-- Tim Watts

[sm_jamieson]

How much grease is actually likely to be in the air ? Also, surely you can put a lid on the pans a lot of the time. That said, we also have an electric steamer. At present we use it for a half hour in the unfinished room and the steam does not cause any major problems. The room has a slightly vaulted ceiling and I guess the steam goes up there. Still I have to have 60l/s (216 m^3/hr) for the room or half that via a hood for the regs. Something like this is in no way sufficient:

main requirement in the light of that is the regs and quietness. And I want to be able to turn things down a bit after the BCO has gone ! Really I'm still just as undecided as before. Heat recovery at the extract rate required seems unfeasible without spending more that the lost heat would cost ! Simon.

[Skipweasel]

I refurbished a house near hear recently. The kitchen ceiling was caked in grease - I wish they'd had an extractor - and used it.

Then again, the tenants were hardly the caring sort - this is the state the downstairs loo was in when I started...

kitchen was, if anything, worse. More maggots and shit for a start.

[Skipweasel]

A friend has them and they seem quite good, but have a serious design flaw. To clean grease, what you really need is a dunk in caustic soda. Which ain't a good idea of the grid is made of aluminium wire.

Silly sods.

One day I'll make him a SS set.

[Mr Pounder]

Are you really serious with that pic?

Mr Pounder

>

[Tim Watts]

Enough - given how greasy the adjacent cupboards became in my last house (lots of wok frying).

Our type of wok cooking tends to require no lid.

I've not felt the steam build up - but there is some staining in the hall ceiling right outside the kitchen door (ceiling is cold there due to building work). Almost looks like a leak but as there is no evidence of a leak from above, I can only conclude it must be due to steam build up.

would be about 7 full room air changes per day - though I wonder how much faster it extracts on "boost".

That would be a key factoid I'd be looking at.

One thing I have observed in the bathroom though, is that if one leaves the room to steam up it takes a while to dry it out post event with the extractor (condensate on the toilet cistern) - but if the extract fan is on prior to a bath and remains on for 15 minutes post bath, it is enough to prevent excessive humidity build up (zero condensation, meter says about 80% peak RH) in the first place.

I wonder how much extraction is actually necessary to placate condensation in a 21m2 kitchen as opposed to dealing with it after the fact?

It's a very good question. How much of a problem are we trying to solve?

eg - if we are primarily CH (or electric) which dry the air, then humidity injection from cooking is a good thing, upto a point. In summer, we'd probably have some windows open anyway.

How much cooking steam can the air in a house buffer before the humidity rises far enough to be a condensation problem?

Do we therefore need a massive extraction rate on a large kitchen that is well connected to adjacent rooms - or just minimal extraction to keep the RH to manageable levels?

[Tim Watts]

Arrgh!

Makes you wonder what the hell the landlord (or his agent) were doing? Don't people care about properties they own? First sign of this and he should have given them the boot.

I have never seen even the mouldiest student house even 1% as bad as that. Flakey, cheap fittings, carpets a bit suspect - but basically clean.

Cheers, Tim

-- Tim Watts

[Tim Watts]

SS would be a key requirement in my book.

Ali is a very very stuid choice...

Cheers, Tim

-- Tim Watts

[Dave Plowman (News)]

Were the tenants responsible for the mould on the walls?

[ARWadsworth]

If I ever go back I'll take a photo of the toilet that has been used for a while and has no water...........................

[Dave Plowman (News)]

Mine is mounted on an outside wall - and vents straight out from the back of the unit. So no need for expensive charcoal filters - just a simple foam one. So that would make heat recovery more of a problem.

[Skipweasel]

Yup. The rest of the house wasn't much better. Part of it were worse.