Small house MVHR Design Critique

[karesz0304]

Hi all,

 

I'm looking to retrofit install a Vent Axia Sentinel Kinetic Advance SX MVHR system in this small 109 m2 house and DIY the ventilation duct system. The current ceiling height is 3 m and I'd like to build a 30 cm deep false ceiling for the duct system. I paid for the attached design (BPC) but I'm a little worried as the designer keeps emphasising that "We do not provide an "as built" design service, we only provide a layout which is a visual guide and not a plan." 

 

I thought I would have fresh eyes take a look to see if there are any glaring errors. Any opinions welcome! 

 

Thanks 
K

Edited March 31, 2020 by karesz0304
mirror edit

[dpmiller]

the design doesn't recognise things like joist direction and obstacles to routing.

 

I'd wonder if the two l/h bedrooms might benefit from two duct runs each based on the length of run

I'm intrigued  by the supply vent in the stairwell

finally perhaps the vents in the kitchen/dining/living end might need to be farther over to the right? Where will the cooker be?

[ProDave]

What's the extra inlet vent in the middle of the kitchen / diner for?  I would have thought inlet at dining end and extract at kitchen end was enough.

 

What is the stairwell thing?  If there is a stairwell then there is an upstairs so where is the vent plan for that?

 

Is it a bedroom at the moment with some plan in the future to convert the loft?

 

Agreed put kitchen / diner vents on the centreline of the room, if for no other reason than aesthetics.

[karesz0304]

  On 30/03/2020 at 17:16, dpmiller said:

the design doesn't recognise things like joist direction and obstacles to routing.

 

I'd wonder if the two l/h bedrooms might benefit from two duct runs each based on the length of run

I'm intrigued  by the supply vent in the stairwell

finally perhaps the vents in the kitchen/dining/living end might need to be farther over to the right? Where will the cooker be?

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This is an ICF house and no obstacles other than walls. 

At what length do we need double the duct run? any baseline number? 

At the moment, that's a study room and we'll convert the loft later on.

Black is the sink, red is the cooker however we have a cooker hood.

 

[karesz0304]

  On 30/03/2020 at 17:30, ProDave said:

What's the extra inlet vent in the middle of the kitchen / diner for?  I would have thought inlet at dining end and extract at kitchen end was enough.

 

What is the stairwell thing?  If there is a stairwell then there is an upstairs so where is the vent plan for that?

 

Is it a bedroom at the moment with some plan in the future to convert the loft?

 

Agreed put kitchen / diner vents on the centreline of the room, if for no other reason than aesthetics.

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They said the size of the dining/living room (35m2) requires one single and one double inlets. I would of thought one dining/one living room or a double inlets was enough on the supply end.

We're planning to convert the loft at a later date. 

It was there first, but I wanted to get as far from the cooker as possible and the designer recommended to put above the kitchen sink. 

[JFDIY]

If you're going to convert the loft, I'd factor this into the MVHR design now: ensure the unit is big enough and plan the duct runs, run them in and cap the ends, then join onto them later on.

 

 

[ultramods]

Where possible I would try and keep inlet vents as far away as possible from headboard end of beds and sofa/chair positions, to avoid feeling "draughts".

[epsilonGreedy]

Should the external intake and exhaust cowls be further apart?

[ProDave]

What is the size of that living / kitchen / dining room?

[MikeGrahamT21]

Is it just me or does there seem to be a lack of cross ventilation? The vents could be further away from the doors in my opinion to get better cross ventilation in some of the rooms.

[Bitpipe]

You'll potentially have a 'dead zone' along the back of the living / dining room.

 

I would move the extract so it's near the cooker hood - I assume this is re-circulating vs extracting to outside?

 

That way the MVHR can remove the extract from the cooker hood and also create a cross draught for the whole run of rooms.

 

For the two end bedrooms, I'd extend the supply ducts into the far corners of each room as otherwise the fresh air will go straight under the door to the nearest extract.

[karesz0304]

  On 31/03/2020 at 07:58, ProDave said:

What is the size of that living / kitchen / dining room?

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35m2

[ProDave]

  On 31/03/2020 at 08:35, karesz0304 said:

35m2

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My Kitchen / diner is 7m by 5m so as it happens 35 m2 Mine is working just fine with one inlet at the kitchen end and one extract at the dining end.  Both fed by twin 75mm ducts.

 

I will eventually fit a recirculating cooker hood but I don't have one at the moment.

 

So ithink you can forget the single duct extra inlet in the middle of the room.

[karesz0304]

  On 31/03/2020 at 08:04, Bitpipe said:

You'll potentially have a 'dead zone' along the back of the living / dining room.

 

I would move the extract so it's near the cooker hood - I assume this is re-circulating vs extracting to outside?

 

That way the MVHR can remove the extract from the cooker hood and also create a cross draught for the whole run of rooms.

 

For the two end bedrooms, I'd extend the supply ducts into the far corners of each room as otherwise the fresh air will go straight under the door to the nearest extract.

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Cooker hood is re-circulating. Thanks for the input. 

[Bitpipe]

  On 31/03/2020 at 08:40, karesz0304 said:

Cooker hood is re-circulating. Thanks for the input. 

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No problem - if you visualise how the air goes from supply to extract and try to maximise that for each room then you should be ok. 

 

In the bathroom, try and locate the extract close to the shower or bath.

 

Given the extracts are fewer in number and usually have a double run of ducting, they will extract at a much higher rate than the supplies deliver air so not as critical to have them in the far corners.

 

Not sure that dining room supply will do a whole lot to be honest.

[ProDave]

Don't forget if you are planning to convert the loft later, to size the MVHR unit and manifolds to allow addition of the upstairs vents later on.

[Gone West]

  On 30/03/2020 at 15:46, karesz0304 said:

I thought I would have fresh eyes take a look to see if there are any glaring errors

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Both attenuators are commented as being on extract circuit. I wouldn't want the external vents to be any closer than 1.5m, ideally at least 3.0m apart. I would ensure that the 125mm diameter ducting at the vents is not restricted in any way so as to allow full flow of air. Often 125mm 90 degree cowls are fitted which look smart but do restrict air flow.

[karesz0304]

The designer from BPC is very helpful and here is the latest design. The addition of the upstairs vents are included and because of this an additional extract was required to balance the system. I also decided to get a 15pt Manifold with a 200mm spigot today rather than buy an additional manifold with a T point in the future. 

 

Any final improvement you would recommend? 

 

I really appreciate your help