MHRV - Extract & Exhaust locations

rampantbunny

I'll be DIYing my MVHR install in the coming months.
It has been designed and will be commissioned by a professional, but the design drawing doesn't specify the exact locations of the in-ceiling extract and exhaust vents.

Can anyone offer advice on where these should be positioned?

Before anyone suggests that my expert should be telling me this, he's one of those nice fellas that just doesn't do communication very well.
Patience should come in a box with a big stick, but I'll keep that in reserve for another while.

893bet

Mine were put on East gable wall around 5meters apart. Installer made the call as I asked where he recommended.

rampantbunny

893bet wrote: »

Mine were put on East gable wall around 5meters apart. Installer made the call as I asked where he recommended.

Thanks for info 893.
The gable exhaust and intake are accounted for, but the actual room/ceiling vent locations are not..these are what I'm looking for.
Sorry, should have been more clear.

BarneyMc

No expert but I think you should keep vents deep into rooms and not just a few steps into the room. Also keeping runs in straight lines is good. Avoid placing over seated areas as it can cause a slight draught. Dont put extract in kitchen too close to cooker. Biggest fear would be not getting an efficient run so I really think you should get a pro to look at it for you.

MicktheMan

System design is THE most important aspect to an effective and efficient mvhr system. Getting an experienced ventilation specialist is key. I have seen so many "diy" installations where the layout / design is so poor that the overall functionality of the system is severely compromised to the point of being not fit for purpose.
So.... insist that the designer specifies the exact locations for you (assuming that the "designer" actually knows how to do this!)

Calahonda52

rampantbunny wrote: »

I'll be DIYing my MVHR install in the coming months.
It has been designed and will be commissioned by a professional, but the design drawing doesn't specify the exact locations of the in-ceiling extract and exhaust vents.

Can anyone offer advice on where these should be positioned?

Before anyone suggests that my expert should be telling me this, he's one of those nice fellas that just doesn't do communication very well.
Patience should come in a box with a big stick, but I'll keep that in reserve for another while.

Okay, Lets have some hard numbers here from your non comms pro.
1 Min fresh air required
2. Min extract calc
3 Min air change change calc.
4 Part L requirements.
5 length of intake and exhaust ducts.
6 Duct diameter.
7 Elec efficiency of unit
8 TFA of house.

rampantbunny

MicktheMan wrote: »

System design is THE most important aspect to an effective and efficient mvhr system. Getting an experienced ventilation specialist is key.

I have seen so many "diy" installations where the layout / design is so poor that the overall functionality of the system is severely compromised to the point of being not fit for purpose.
So.... insist that the designer specifies the exact locations for you (assuming that the "designer" actually knows how to do this!)

Maybe I'm wrong Mick, but are you suggesting that I don't have an experienced ventilation specialist employed? This based on my not yet having completed drawings (with exact vent locations)?
I'm getting that from the use of double-quotes around the word "designer", and to be honest the whole of that sentence. It might be a bit on the sarcastic side.
Sorry if I'm misinterpreting.

I'm here for a rule of thumb, not final design input...if anyone can advise/offer opinion.

rampantbunny

Calahonda52 wrote: »

Okay, Lets have some hard numbers here from your non comms pro.
1 Min fresh air required
2. Min extract calc
3 Min air change change calc.
4 Part L requirements.
5 length of intake and exhaust ducts.
6 Duct diameter.
7 Elec efficiency of unit
8 TFA of house.

Hi Calahonda.

I'll edit my original post but I'm only looking for guidelines e.g. vents to be kept away from or near to door opes, or windows etc...
With this info, I can show my other half where the vents might go and we can look at preemptively planning dropped ceilings, light locations etc. My professional will be contactable at some point so I'm not relegating him from the equation - he'll have final input.

Just out of interest, do you need the above detail to plan exact vent locations? Seems pretty forensic/thorough and I'd have expected you to need room layout/dimensions also.

rampantbunny

BarneyMc wrote: »

No expert but I think you should keep vents deep into rooms and not just a few steps into the room. Also keeping runs in straight lines is good. Avoid placing over seated areas as it can cause a slight draught. Dont put extract in kitchen too close to cooker. Biggest fear would be not getting an efficient run so I really think you should get a pro to look at it for you.

Cheers Barney. System calculated and designed by pro...includes duct runs. I checked over it all to make sure the runs couldn't be shortened without introducing bends. Some runs we did shorten when I decided to take a duct through a wardrobe here and there, but I'm pretty happy that that end of things is as good as it can be.

runawaybishop

rampantbunny wrote: »

I'll be DIYing my MVHR install in the coming months.
It has been designed and will be commissioned by a professional, but the design drawing doesn't specify the exact locations of the in-ceiling extract and exhaust vents.

Can anyone offer advice on where these should be positioned?

Before anyone suggests that my expert should be telling me this, he's one of those nice fellas that just doesn't do communication very well.
Patience should come in a box with a big stick, but I'll keep that in reserve for another while.

Both should be near center of room. Extracts shouldn't be positioned over windows, exhausts shouldn't be positioned directly over where people will be., i.e couches and bed.

MicktheMan

rampantbunny wrote: »

Maybe I'm wrong Mick, but are you suggesting that I don't have an experienced ventilation specialist employed? This based on my not yet having completed drawings (with exact vent locations)?
I'm getting that from the use of double-quotes around the word "designer", and to be honest the whole of that sentence. It might be a bit on the sarcastic side.
Sorry if I'm misinterpreting.

I'm here for a rule of thumb, not final design input...if anyone can advise/offer opinion.

Designer in quotes because any drawings should have exact locations specified. Hence my scepticism.

Rules of thumb:
Extracts directly over showers, baths but not directly over cooker
Supplys located such that air gets "pushed" towards buffer zone / extract leaving little dead space.
Where supply and extract in same room (large open plan living / kitchen) then make sure no short circuiting.
Having vents above seating areas generally isn't a problem if the correct vent cover/grill is used.

MicktheMan

runawaybishop wrote: »

Both should be near center of room. Extracts shouldn't be positioned over windows, exhausts shouldn't be positioned directly over where people will be., i.e couches and bed.

Wrong.

runawaybishop

MicktheMan wrote: »

Wrong.

Eloquent response. Why?

MicktheMan

runawaybishop wrote: »

Eloquent response. Why?

See below

MicktheMan wrote: »

Designer in quotes because any drawings should have exact locations specified. Hence my scepticism.

Rules of thumb:
Extracts directly over showers, baths but not directly over cooker
Supplys located such that air gets "pushed" towards buffer zone / extract leaving little dead space.
Where supply and extract in same room (large open plan living / kitchen) then make sure no short circuiting.
Having vents above seating areas generally isn't a problem if the correct vent cover/grill is used.

rampantbunny

MicktheMan wrote: »

Designer in quotes because any drawings should have exact locations specified. Hence my scepticism.

Rules of thumb:
Extracts directly over showers, baths but not directly over cooker
Supplys located such that air gets "pushed" towards buffer zone / extract leaving little dead space.
Where supply and extract in same room (large open plan living / kitchen) then make sure no short circuiting.
Having vents above seating areas generally isn't a problem if the correct vent cover/grill is used.

Thanks Mick.
If I questioned the designers ability based on an incomplete layout drawing, I'd have to do that for every trade that has walked through the door so far. None have completed their jobs without making a mistake...foundations, brickie, roofer, windows. I've accepted this as an integral part of the construction industry but as long as the mistakes don't impact too much, I'm fine with it.

To be fair, "DIY" (your first post) would also cause me raise a question. It's almost a dirty word, but for self-builders it is the unavoidable integral part.

Again, thanks for the info.

BarneyMc

MicktheMan wrote: »

Wrong.

I think what Mick means is for rooms with either an extract or input, but not both, they should be centrally located?

runawaybishop

MicktheMan wrote: »

Designer in quotes because any drawings should have exact locations specified. Hence my scepticism.

Rules of thumb:
Extracts directly over showers, baths but not directly over cooker
Supplys located such that air gets "pushed" towards buffer zone / extract leaving little dead space.
Where supply and extract in same room (large open plan living / kitchen) then make sure no short circuiting.
Having vents above seating areas generally isn't a problem if the correct vent cover/grill is used.

I don't disagree per se with what you have said but I do disagree that my advice was wrong.

Without seeing plans all this is general ofc.

In the majority of wet intake rooms you'll have sources placed along walls and often have multiples (i.e bath/shower/sink) in one room - siteing the intake in the middle is the safest bet but tbh it makes very little overall difference.

Vents will still produce airflow and its not difficult to just not site them directly over seating/sleeping areas. The majority of vent covers that seem to be supplied are those mushroom ended ones that do produce a cone of air.