1 or 2 extract points in kitchen?

[j_s]

Have made a start to mvhr. It's all in the loft, just need to tape and insulate all the pipework for the distribution boxes etc. All the upstairs room plenums (grey units that the extract/air intake adjustable covers fit to - bpc call them that so apologies if it's the wrong term) are in place. I am using the semi rigid ducting with 2 ducts going to bathrooms and kitchen and main rooms and 1 to WC etc. 

 

My other half cooks, bakes, makes jam, the lot really so will 1 extract point in the kitchen be enough? Have a powerful extractor over the hob that will be converted to recirculation only. Should I consider a second extract ? Kitchen is around 4.5m x 3.1m if that helps at all?

 

Thanks

James

[Jeremy Harris]

Our kitchen is around 4.5m x 4m and is fine with a single extract to the MVHR.  On boost it flows way over the 13l/s required by the regs.

Edited September 18, 2017 by JSHarris
typo

[j_s]

Thanks jsharris. What I might do if there is enough, is run another 2 runs of duct to the kitchen so I then have an option in the future. 

[le-cerveau]

I am planning 2 extract points in my kitchen with 4 ducts (2 to each), but I have a 34m² open plan kitchen in a 108m² open plan area and a planned extract of 22l/s (80m³/h) due to house size.  I will be having re-circulators over my hob also.

 

I start the first stage install next month.

Ground floor plan (showing ceiling plan suspended ceiling).

[Bitpipe]

We also have an open plan kitchen / diner / living area, think of it as 3 quadrants of a 10mx10m square.

 

BPC recommended two extracts in the kitchen, one in the corner and one between the hob (which has an overhead recirculating extractor) and oven wall. All my extracts have double runs of duct, the combined kitchen extract rate at boost is over 30l/s.

 

While this sounds excessive, looks like I needed the additional capacity if only to balance the supply - this was my main challenge in tuning the system last week (we have extracts in each bathroom and utility, but lots of single duct supply vents in all other rooms, inc basement).

 

I was doing some griddle cooking at the weekend and things got a touch smokey, even with the MVHR is boost, it was not clearing quick enough so I resorted to opening a few windows - which goes to prove that MVHR is designed for background ventilation rather than heavy duty extraction.

 

 

[jack]

15 hours ago, j_s said:

My other half cooks, bakes, makes jam, the lot really so will 1 extract point in the kitchen be enough? Have a powerful extractor over the hob that will be converted to recirculation only. Should I consider a second extract ? Kitchen is around 4.5m x 3.1m if that helps at all?

 

I'd be concerned about significantly changing what BPC have designed you, without checking with them as to whether the changes will unbalance things. If you increase the extraction from the kitchen, you'll have to balance that with more supply elsewhere. Have you taken this into account?

 

8 minutes ago, Bitpipe said:

I was doing some griddle cooking at the weekend and things got a touch smokey, even with the MVHR is boost, it was not clearing quick enough so I resorted to opening a few windows - which goes to prove that MVHR is designed for background ventilation rather than heavy duty extraction.

 

That's my experience too. We have a single run and a double run for our roughly 6m x 6m kitchen/dining area, and even on full boost (400m³ per hour) it isn't enough to keep the kitchen clear if we're doing something really smokey. I think it's partly because we have high ceiling (nearly 3m), which means that smoke can disperse somewhat before it gets anywhere near an extractor.

[j_s]

That's a good point Jack, I'll give them a call and see what they think.

 

Thanks all.

[Kay Pee]

Interested in getting thoughts on extract for high kitchen utilisation..... my other half uses the kitchen (~4m x 4m, 2.7m ceiling) in a commercial capacity and we currently have a 'big boy bertazzoni' ? 800m3/hr extract which makes some noise on full tilt! To be honest, it's never really used on full power, only on minimum when something is boiling on the hob. Useful the odd time on full power when things get smokey as folk above have mentioned, but there's also an openable window for those 'incidents'...

 

I'm thinking 2 extract points would be a good idea here, perhaps one closer to the cooking source, plumbed into the back of the cooker hood (I can get at this through the chimney void behind it.) and one in the ceiling corner as per normal.

 

Any thoughts?

 

Still looking at sizing the unit, perhaps a Blauberg SB250 for our 3 bed semi (~110m2, 1 bathroom) which would be slightly oversized as we only need 39l/s as per the regs.

 

I'm loving this forum, lots of useful information and tinkerings ?

[Ferdinand]

10 hours ago, Kay Pee said:

Interested in getting thoughts on extract for high kitchen utilisation..... my other half uses the kitchen (~4m x 4m, 2.7m ceiling) in a commercial capacity and we currently have a 'big boy bertazzoni' ? 800m3/hr extract which makes some noise on full tilt! To be honest, it's never really used on full power, only on minimum when something is boiling on the hob. Useful the odd time on full power when things get smokey as folk above have mentioned, but there's also an openable window for those 'incidents'...

 

I'm thinking 2 extract points would be a good idea here, perhaps one closer to the cooking source, plumbed into the back of the cooker hood (I can get at this through the chimney void behind it.) and one in the ceiling corner as per normal.

 

Any thoughts?

 

Still looking at sizing the unit, perhaps a Blauberg SB250 for our 3 bed semi (~110m2, 1 bathroom) which would be slightly oversized as we only need 39l/s as per the regs.

 

I'm loving this forum, lots of useful information and tinkerings ?

 

On the wider design thoughts.

 

Have you run some thought experiments / scenario plans about how it will work based on the possible routes for development for the business? I would look at - for example - taking care that the kitchen will still work to a necessary extent domestically whilst business is in full swing. That might involve having a separate sink at the other end, or careful thought about the utility.

 

eg How will you practically have a friend around for a cup of tea and a biscuit, or make lunch, when your beloved is icing cakes on the island, butchering an ostrich in the main sink, or making 5 gallons of raspberry vinegar? Or how will it and you cope if 1:4 cookery courses need to be run? Your normal routine needs to continue to work.

 

F

Edited June 13, 2019 by Ferdinand

[Kay Pee]

13 hours ago, Ferdinand said:

eg How will you practically have a friend around for a cup of tea and a biscuit, or make lunch, when your beloved is icing cakes on the island, butchering an ostrich in the main sink....

 

 

LOL at the thought of her standing at the sink with half an Ostrich carcass, especially as she (little pink kitchen) specialises in vegetarian catering.

 

The kitchen has been in operation for 3 years now, and is signed off by the local council. There's no utility area and the design is pretty fixed, yet manages to stretch to the required capacity. There are times I've come home to find a film crew in the kitchen which makes for some interesting polite chat as I stand there in my wet lycra just off the bike.... ?

[joth]

23 hours ago, Kay Pee said:

perhaps one closer to the cooking source, plumbed into the back of the cooker hood (I can get at this through the chimney void behind it.) and one in the ceiling corner as per normal.



I forget who but one MVHR supplier recommended against this, as you don't want grease etc straight off the fat pan getting up the ventilation pipes where it is hard to clean. Much better to have it line the walls of the kitchen instead, one assumes.  having good clean filters in the  (recirculating) hood is going to help reduce that.

[Jeremy Harris]

8 hours ago, joth said:

I forget who but one MVHR supplier recommended against this, as you don't want grease etc straight off the fat pan getting up the ventilation pipes where it is hard to clean. Much better to have it line the walls of the kitchen instead, one assumes.  having good clean filters in the  (recirculating) hood is going to help reduce that.

 

 

That's what I did, for the same reason.  I also went for a single, double ducted, extract terminal in the kitchen, placed right in the corner opposite the door (the door is where replacement fresh air comes in from other rooms).  The principle is to have as long an air path from the extract point to the fresh air supply point as possible, to allow for the maximum diffusion of fresh air across the room.  The same principle applies to all MVHR room terminal locations, make the flow path as long as possible across each room.

[MJNewton]

5 hours ago, JSHarris said:

I also went for a single, double ducted, extract terminal in the kitchen, placed right in the corner opposite the door

 

Did/do you have a grease filter in that extract? I've bought quite a few of my MVHR components (it's a varied mix of suppliers!) from BPC and I threw in a couple of their coarse filters to my last order in case they may be of some benefit to my kitchen extract to help catch some airborne grease without causing undue flow restriction. I am still mid-installation and so don't how it will work out though. We are toying with not having an (recirculating) extractor hood as this will be an open-plan kitchen/diner/lounge where functional considerations are having to compete against 'minimalist' design pressures from the wife!

Edited June 14, 2019 by MJNewton

[Jeremy Harris]

Just now, MJNewton said:

 

Did/do you have a grease filter in that extract? I've bought quite a few of my MVHR components (it's a varied mix of suppliers!) from BPC and I threw in a couple of their coarse filters to my last order in case they may be of some benefit to my kitchen extract to help catch some airborne grease without causing undue flow restriction. I am still mid-installation and so don't how it will work out. We are toying with not having an (recirculating) extractor hood as this will be an open-plan kitchen/diner/lounge where functional considerations are having to compete against 'minimalist' design pressures from the wife!

 

 

No, and so far we've not had a problem, the terminal that tends to get the dirtiest is the extract on the shower room, which for some reason always seems to attract fluff (I blame the obsession with fluffy towels...). 

 

Mind you, we rarely fry anything, so we're far from being a worst case when it comes to likely muck in the kitchen extract.  Also, because the extract terminal is near the corner of the kitchen, a couple of metres or so away from the hob, any grease that does get airborne most probably condenses out long before it reaches it.

[MJNewton]

Okay, thanks. We too are not heavy fryers  and so similarly probably don't have much of a problem to solve either. Am I right in thinking that you didn't put an extractor hood in either (just the wiring and potential for mounting)?

 

Incidentally, having seen your HB+ terminals and liked their appearance I went for them also. I am assuming they'll be pretty easy to keep clean (I know what you mean about bathroom fluff!), and of course there's no issue of disrupting the balance when removing them given the restrictions being set back at the manifolds so I am confident I'll be pleased with that choice.

[Carrerahill]

I'd like to see what you have bought and are installing - I want to put a system into our extension (which will have the kitchen) and connect in some of the downstairs rooms.

[Jeremy Harris]

13 minutes ago, MJNewton said:

Okay, thanks. We too are not heavy fryers  and so similarly probably don't have much of a problem to solve either. Am I right in thinking that you didn't put an extractor hood in either (just the wiring and potential for mounting)?

 

Incidentally, having seen your HB+ terminals and liked their appearance I went for them also. I am assuming they'll be pretty easy to keep clean (I know what you mean about bathroom fluff!), and of course there's no issue of disrupting the balance when removing them given the restrictions being set back at the manifolds so I am confident I'll be pleased with that choice.

 

I did fit a bit of ply and the wiring in above the ceiling so that we could retrofit a recirculating hood, but we've decided we just don't need one.  The kitchen stays steam-free and cooking smells don't seem to either linger or escape from the kitchen, so I think we'll just stick with the MVHR extract.

 

Cleaning the terminals is really easy, as they just pop out and and can be put in the dishwasher.

[MJNewton]

1 hour ago, Carrerahill said:

I'd like to see what you have bought and are installing - I want to put a system into our extension (which will have the kitchen) and connect in some of the downstairs rooms.

 

Me, or the OP (j_s)?

[Carrerahill]

25 minutes ago, MJNewton said:

 

Me, or the OP (j_s)?

Anyone who is willing to show me! So yes, you if you could!

 

I want a fairly simple system just to improve the air quality in our house and let us ventilate year round without needing windows open. 

[joe90]

With our kitchen / diner I put a carbon filter cooker hood (recirculating) in one corner, MVHR extract in the other kitchen corner and a MVHR air input at the other end of the room that’s the dining end, frankly we hardly ever switch the cooker hood on!

[MJNewton]

1 hour ago, Carrerahill said:

Anyone who is willing to show me! So yes, you if you could!

 

I want a fairly simple system just to improve the air quality in our house and let us ventilate year round without needing windows open. 

 

Happy to. One day (when/if I finish it!) I'll do a proper write-up as I think some aspects of my system could be of interest to other retro-fitters that don't the have the luxury of open ceilings, webbed joists etc of a new build (okay, we don't the stresses either! )

 

As brief background, my system was born out of the desire not to spend loads of money and effort on insulting our new open-plan extension only to have (at extra cost) trickle vents added to the already-expensive lift-and-slide doors. As with many of my ideas and musings next thing I'm doing is looking to ventilate the whole house with MVHR...

 

I could see strengths and weaknesses with different components from different manufacturers/suppliers and so, taking advantage of the cross-compatibility of the 75/63mm radial duct systems hand-picked different parts for different reasons:

 

- MVHR Unit - Titon HRV 1.25 Q Plus Eco - Had all the features I desired (e.g. right size, summer bypass, generic filter baskets etc) but most importantly was available cheap (£350 I think?) from a seller on eBay who was involved in ripping out hundreds(?) of them from a development to replace them with the next size up as per the contracted spec. They'd only been commissioned and the properties yet to be handed over to residents. I visited the guy at his house to collect it and am convinced by this back story. Came fully boxed with all the extras (from the new units), and seem good quality with ebm-papst EC fans and Recair heat exchangers.  Happy to pass on the contact details to him if others are interested as I think he's still got some left.

- Control System - My brother keeps reminding me that he never touches his MVHR unit (other than filter changes) however the engineer in me still wants to monitor/control it. Rather than spend hundreds on the proprietary Titon control units I will eventually be building a Pi-based controller to monitor/graph performance and operating states, as well as to provide more configurable automatic controls (holiday mode, humidity-based switching, summer bypass/purging, PWM motor control etc). In the meantime I will leave the unit to do its stuff but I am fitting momentary boost switches in place of the existing extractor fan isolators just to give some manual control should it be required (and also in case we ever move on - I don't think the new owners will appreciate being left a hand-written user guide and downlink link to my bespoke Android app!).

- Ducting - Airflow Airflex Pro - Whilst all 75/63mm ducting is seemingly interchangeable that is not to say they are all made the same. I've handled some that has been far less flexible than the Airflex Pro stuff and so went for this as I knew it was really good quality.

- Distribution Manifolds - Blauberg 8-Port - I was going to make my own out of ply but at only £35 each I couldn't resist. They were easy to line with acoustic foam and I will be combining them with their own ducting adapters and (expensive - might DIY) restrictors to adjust the flow at this end rather then the ceiling terminals (reduces room noise and avoids unauthorised fiddling!).

- Silencer - Blauberg 600mm - Again, another cheap offering from Blauberg at less than £30. Opted just to fit one on the supply side, but have designed the extract pipework to allow an easy swap-in if need be.

- Ceiling Terminals - HB+ Conus Airvalve - Chosen after I saw @JSHarris's setup and liked them both for their aesthetics (slightly less 'office toilet' than some as my wife put it!) but also that they are designed to work with manifold-mounted restrictors (i.e. they can't be screwed in/out). I bought them from a supplier in the Netherlands as even with shipping there was still quite a saving over UK suppliers.

- Terminal Adapters - Domus - I went for these for those locations that I could easily access (kitchen, lounge, dining room due to ceilings being down; top bedroom, en suite and dressing room due to loft access) as they were a bit cheaper than some others, are nice and compact etc. Not much to choose between really, although some seem very expensive for what they are. For other locations where I only had through-the-ceiling access I've gone for a bit of a Heath Robinson lash up that I could install through a 125mm hole from below consisting of a 125mm 90 degree elbow combined with a 125mm to 75mm reducer.

 

I think that's pretty much it, aside from all the ancillaries, fixed piping etc. In total I think I've spent £1200 in total which I don't think is too bad for a 100m 11-port (12 duct) system. Yes, more than the trickle vents in the doors that kicked this adventure off but hopefully of more functional value.

 

Edit: Apologies to @j_s; I wansn't intending to deviate the thread with all this!

 

 

 

Edited June 14, 2019 by MJNewton