MHRV & Hob Extractor Hood

Mike2006

For those who already have a MHRV installed:

You obviously want to keep the house as airtight as possible but your hob extractor hood needs to be connected to the external air.

How do you do this?

a. Connect hood to MHRV system?
or
b. Connect Extractor hood as normal and seal as best you can?
or
c. Put a damper valve on extractor hood that opens when hood is running and closes when it isn't, thus sealing system once again?

Mike.

CJhaughey

Mike2006 wrote: »

c. Put a damper valve on extractor hood that opens when hood is running and closes when it isn't, thus sealing system once again?

Mike.

I did it this way.

gizmo555

Mike2006 wrote: »

For those who already have a MHRV installed:

You obviously want to keep the house as airtight as possible but your hob extractor hood needs to be connected to the external air.

How do you do this?

a. Connect hood to MHRV system?
or
b. Connect Extractor hood as normal and seal as best you can?
or
c. Put a damper valve on extractor hood that opens when hood is running and closes when it isn't, thus sealing system once again?

Mike.

Or (d) - get a cooker hood with graphite filters running in recirculation mode to deal with grease & cooking smells and let the HRV deal with the steam. There is a lot of this type of cooker hood on the market.

After all, the cooking is generating heat that you would like the HRV to recover . . .

Juantorena

gizmo555 wrote: »

Or (d) - get a cooker hood with graphite filters running in recirculation mode to deal with grease & cooking smells and let the HRV deal with the steam. There is a lot of this type of cooker hood on the market.

After all, the cooking is generating heat that you would like the HRV to recover . . .

I'm planning to do it this way....

sas

gizmo555 wrote: »

Or (d) - get a cooker hood with graphite filters running in recirculation mode to deal with grease & cooking smells and let the HRV deal with the steam. There is a lot of this type of cooker hood on the market.

Or possibly go for a system design for low energy houses such as www.berbel.de

No filters required apparently.

I've no idea where you get these (apart from germany obviously) but I thought it might be useful to people anyway.

Juantorena

sas wrote: »

Or possibly go for a system design for low energy houses such as www.berbel.de

No filters required apparently.

I've no idea where you get these (apart from germany obviously) but I thought it might be useful to people anyway.

I can pm (British) suppliers for these. Not cheap (island hoods 2 - 2.5k Sterling) and do have a carbon filter for odours but they claim their grease filter ensures proper - and longer - functioning of the carbon filter.... Standard fitting requirements.

sas

Juantorena wrote: »

I can pm (British) suppliers for these. Not cheap (island hoods 2 - 2.5k Sterling) and do have a carbon filter for odours but they claim their grease filter ensures proper - and longer - functioning of the carbon filter.... Standard fitting requirements.

Please do send on the details.

Gasket

Hi All,
I'm at the stage of my build where i have to either drill the wall for the cooker extract, or decide to get a recirculating extractor. I haven't been able to source a non-return valve anywhere for the extract duct- has anyone any experience of this?
On the other hand, I'm not sure if the recirculating extractor will cause the HRV duct to take in grease.

Has anybody got any advice you can give- how are you managing the cooker extractor with the HRV?

Coles

Best to have a separate extract for the cooker and keep the grease out of the HRV. You don't need to use the cooker extract much anyway so the amount of heat lost is not significant compared to the cost and hassle of cleaning your HRV filters and ducts.

windyboy

Hi,

I would also recommend Berbel as SAS mentioned. I first saw an island Berbel extractor fitted in a kitchen on a Project-Oecotop House in Dublin when I was researching and toying with the idea of imported German timber frame house back in 2009. In the end I built an airtight ICF house and fitted a Paul HRV. I wanted a recirculation fan that I could trust would deal with the grease effectively so I ended up buying their Island hood Classicline BIH 90 CL LHS (re-circulated air).

The following pages from Berbel's website give a good overview of their patented 'aero performance' technology.

http://www.berbel.de/uk/know-how/berbel-principle-of-operation.html
http://www.berbel.de/uk/know-how/recirculation-technology.html

As you can see they have certification from TÜV that they have a fat separation rate of 95.8% . Id be surprised if there are any other manufacturers on the market that can claim this.

At the time Berbel advised as they do not have a distributor for Ireland they would offer buying directly from them.

I dealt with a very helpful lady called Linda Greve contact details below:

Linda Greve
Export / Marketing
E-mail: L.Greve@berbel.de
Internet: www.berbel.de
Adresse:
Berbel Ablufttechnik GmbH
Sandkampstraße 100
48432 Rheine
Tel.:+49 (5971) 80809-15
Fax: +49 (5971) 80809-10

However as an alternative Linda recommended to buy from the following English agents:

French Connection Kitchens
39a Newmarket Rd
Norwich Norfolk NR2 2HN
Tel: 00441603 760770
info@frenchconnectionkitchens.co.uk

JBA KITCHENS
J. Burgess-Allen Kitchens
5 Gloucester Road
CM15 9ND Brentwood
Tel: 00447739 094384

Maric Developments Ltd
193 Huddersfield Road
HD9 3TT Holmfirth
Tel: 00441484 683466

M&M Bathrooms Ltd
U4, 15-19 Sedgwick Street
PR1 1TP Preston
Tel : 00441772 888860
info@mmbathrooms.co.uk

Space Fitting Furniture
145 Colchester Avenue
CF23 9AN Cardiff
Tel: 00442920 455778

ikon Interiors Ltd
11 Regent Street
LS2 7QN Leeds,
West Yorkshire
Tel: 0044113 2426873
Fax: 0044113 2426878
ikon-interiors@btconnect.com


They are not the cheapest but you get what you pay for!

Regards,

Windyboy

fclauson

I went with recirculating

we do comparatively little frying

blast06

At decision point on this as well. I'm likely to run with a damper controlled vent - i don't the energy loss associated with this is really worth worryin that much about in the bigger scheme of things.
However, my concern is that when the extractor fan is running, does it create a lower air pressure in the house .... i.e.: you are extracting air from the house but your HRV system does not pump in more air to compensate obviously so is it likely that air will from outside will look to force its way in to equalise the air pressure inside and outside the house
Or am i talking nonsense here ?!

fclauson

you'll suffocate and you will not be able to open any outward opening doors as they will be sucked shut !!!! :eek:

In reality your hrv will happily operate imbalanced for a while with more air coming in the supply and then going out via the extractor

One word of caution - if any of your Ubends dry up (which they do in a dry mhrv house and this has to be watched for) then worse case you suck up smelly air from the sewer - it will take you about 4.5 seconds to realise this and then providing you know it might happen another 4.5 seconds to fix it by turning on the tap to refill the bend.

Are you shooting to be passive certified as the damper approach will not be airtight to the levels you need to get sub about 1ach unless its a very very good one

blast06

Thanks for the comments fclauson ! I will wear goggles when i am in the house so in case my eyes are sucked out !

Will keep the u-bend issue in mind .... although as you say it will be more of knowing it as soon as it occurs !

I am not pushing to be passive .... looking to be as good as possible - anything less than 3 is a bonus. Need to look into the dampers.

One other mostly unrelated question. ...... in my kitchen i have an extract vent and a supply vent for the HRV (fairly big room). The extract vent is close to where the cooker will be (only noticed this evening). Are there any regulations on this ? I expected the supply vent would be close to the cooker instead of the extract ??

Cheers.

Brave Harvey

One other mostly unrelated question. ...... in my kitchen i have an extract vent and a supply vent for the HRV (fairly big room). The extract vent is close to where the cooker will be (only noticed this evening). Are there any regulations on this ? I expected the supply vent would be close to the cooker instead of the extract ??

Extract inlets are designed to be in Kitchens, bathrooms, utility rooms, etc to take away any possible odours from cooking, toilets etc. Supply air outlets are designed to living spaces re living rooms, bedrooms etc.