The Sentinel Kinetic Sounds a bit over-complicated. Perhaps more useful in flats linked to a central system.

As it switches to summer by pass when the hood is on its almost the same as having a normal hood vented to the outside - without the risk of gunge-up in the ducting.

We have a recirculating cooker hood and the MVHR inlet is quite far away. I suppose that means what isn't caught in the cooker hood is sticking to the kitchen on its way to the ducting. 18 months in the MVHR is not greasy-gungy at all but I don't fry much and I do wash the filters.

have you looked?

Posted By: RobinB

As it switches to summer by pass when the hood is on its almost the same as having a normal hood vented to the outside - without the risk of gunge-up in the ducting.

Very good point - why didn't i spot that doh! - Anyway that settles it for me. I rarely fry and rarely use an extractor but when I do I want it to take the smells out, so I will vent outside with a sealable vent and take the occassional heat loss.

Hi jms452

Would you be able to whisper the make & model of the recirculating hood to me.

Many thanks

Don't think it is branded but I'll look (it came with the house).

A recirculating cooker hood is just a normal cooker hood without the extract connected and carbon filters fitted - its why they have louvre vents in the top of the 'chimney'.

There are standard carbon cartridges which fit (almost?) all makes - like the one below
http://www.cookerhoodfilter.com/proddetail.asp?prod=RANGEMASTERCHF525%2F0

edit - our is tecnik but as I say most cookerhoods should be convertable for ~£20 extra

Posted By: Sprocket

So we went for a separate dedicated extract vent with an electric valve to seal it when the extract is not in use and we're now doing the same in a second project.

Hi Sprocket, could I have details of the electric valve you used?

Thanks

"I think this has also been discussed on GBF before."

But without a particularly satisfactory solution. I'm trying to work out the same problem for a my new build at the moment. The Itho mentioned above seems hard to track down now - I've not yet called anyone but doesn't seem to appear on their website and listed as 'discontinued' somewhere.

I *think* I read that it also puts the MHRV into summer bypass when activated so again you seem to be adding complexity and reducing choice over an independent extract system without any reduction in heat loss.

If you're going to extract the Berbel insulated wall box looks promising but the lack of published pricing suggests it's not cheap (Berbel hoods are at the high end).
http://www.berbel.de/uk/accessories/wall-boxes.html It does look like it will work with other manufacturers extractors however. Are there any gotchas on going down this route? What integration with the MHVR is needed?

The other alternative I'm looking at is a 'superior' recirculating hood. Ignoring costs for a moment as once you've established the principles you can start looking for a more cost effective equivalent.

Berbel have hoods using Dyson style centrifugal force rather than an aluminium mesh to remove grease and claim a very high level of grease removal (though without knowing what anyone else gets....). They also have a much larger carbon filter (that they claim only needs replenishing every few years rather than 6 monthly)
http://www.berbel.de/uk/know-how/berbel-principle-of-operation.html
http://www.berbel.de/uk/know-how/recirculation-technology.html (can anyone enlighten me as to what a "3 litre' building is?)

Despite Berbel's claims that their extract method is patented Gaggenau seem to use a centrifugal extract on
this model - http://goo.gl/JujzN . Looks a nightmare to clean though based on the user manual.

Finally, and cost getting really high, Bora http://www.boragmbh.com/en/ , claim their downdraft extractor is more efficient " between 200 and 400 m3/h of air. Clever use of flow speed rather than large air volume is our motto". I'm struggling to see how it's different from other downdraft extractors - any clues? Interestingly they also have the option of a 'pro' recirulation unit PUE30 that looks like it has hugely upgraded carbon filters.

The advantage of the 'tabletop' hoods is that theres nothing to bang your head on or block your eyeline and the motor is not at ear level but the disadvantages seem to be that you lose a large chunk of the cupboard(s) under the cooker, have a potentially very difficult extract route and if in recirc mode you're blowing out at foot level rather than ceiling level.

Ah - I thought this was a bit deja-vu. See over here:-

http://www.greenbuildingforum.co.uk/forum114/comments.php?DiscussionID=8848

You can find the Rega dampers we used here:-

http://www.regaventilation.co.uk/category10596/dampers.aspx

We used the circular ADCA model with electric servo driven by the extract fan supply. It's been operational a while now but we haven't cooked anything there so I still can't comment how well it copes.

Posted By: RobinBthanks Sprocket!

Ditto