Anyone used MVHR floor vents?

[Alan Ambrose]

... and which ones did you use?

[Nickfromwales]

13 minutes ago, Alan Ambrose said:

... and which ones did you use?

https://www.ventilationland.co.uk/en_GB/p/ubbink-air-excellent-35sc-floor-grille-metal-white/9079/?gad_source=1&gad_campaignid=19924996771&gbraid=0AAAAAB0qKPDjHUZDh0lNdENfmtPQWtgAw&gclid=Cj0KCQjw953DBhCyARIsANhIZoahCChrTIG36mWPN1kSwPwP0sYxJBVdTQSq_cUyC602wwIIDmcRvbEaAqUqEALw_wcB

 

and 

 

https://www.ventilationland.co.uk/en_GB/p/ubbink-air-excellent-35sc-grille-adapter/8481/

 

Can prob be found cheaper at Air-Haus https://air-haus.com/

[Alan Ambrose]

Nice, thanks. Assume they worked OK?

[Stu789]

Anyone know if it would it be possible / have experience putting these & the associated AE35 ducting in a raft foundation floor?

Planning an open kitchen-diner with vaulted dining room at the end of a bungalow and need MVHR feed-in at the far end of dining room to match with an extract over the kitchen sink.

MVHR expert I spoke with said ducts in floors are used from time to time for vaulted rooms but we didn't talk about floor makeup.

An alternative is route the AE35 ducting in the vaulted roof service void (which requires SV to be at least 50mm) but the grille adapter is then far too deep (287mm) for the SV.

[JohnMo]

3 minutes ago, Stu789 said:

and need MVHR feed-in at the far end of dining room to match with an extract over the kitchen sink.

Do you actually need a feed in the dining area, does your dining area have a door to elsewhere in the house? Or a vertical wall connected to an accessible area in the existing house?

[Nickfromwales]

Nothing stopping both being in the ceilings? Going into the lower insulation layer over a B&B floor is feasible, as long as the duct is say over at least 25mm of insulation, and the duct is pre insulated. 
 

Just a lot of pain for not much gain, and I’d defo do everything in my power to avoid a vent in the floor tbh. 

[Stu789]

24 minutes ago, JohnMo said:

Do you actually need a feed in the dining area, does your dining area have a door to elsewhere in the house? Or a vertical wall connected to an accessible area in the existing house?

Dining room will be at end of the building, only connected to the kitchen.

[Stu789]

13 minutes ago, Nickfromwales said:

...I’d defo do everything in my power to avoid a vent in the floor tbh. 

I'm of the same view as long as it doesn't make the service void massive.  Thx

[JohnMo]

 

6 minutes ago, Stu789 said:

Dining room will be at end of the building, only connected to the kitchen.

Have you looked at coanda effect supply terminals? They look like this and move air across the ceiling about 4 to 5m, before coming down. Maybe easier than floor ducts.

 

[Nickfromwales]

1 hour ago, Stu789 said:

I'm of the same view as long as it doesn't make the service void massive.  Thx

You can use a lower profile rectangular duct, referred to as ‘oval’. 
 

I use it when we’re stuck for service space and because I always try to get the services absorbed into the fabric of each of my clients projects.  
 

 

I used it above, as we wanted the ceilings to be flat all the way to the wall. You can see the adaptors to convert round to oval, and the reason is that oval doesn’t give brilliant flow rates compared to round, so I try to minimise the amount of oval in a circuit.

 

If you wanted to run a long distance, you can simply do two runs of oval which will perform better than one run of round, so there’s ways around any problem and folk pay me to find these solutions. 👍. 
 

Do try to avoid the floor ducts, and if you share pics of where you need to get to/from I’ll try to offer some suggestions for you. 

[S2D2]

4 hours ago, Nickfromwales said:

You can see the adaptors to convert round to oval, and the reason is that oval doesn’t give brilliant flow rates compared to round

Which brand do you recommend for this and do they have a flow rate calculator to check if multiple oval runs are required?

 

I'm about to install my system but running into issues with the drop to downstairs, the easiest route is down a partition wall with a rather inconvenient 72mm gap...

[Nickfromwales]

2 hours ago, S2D2 said:

Which brand do you recommend for this and do they have a flow rate calculator to check if multiple oval runs are required?

 

I'm about to install my system but running into issues with the drop to downstairs, the easiest route is down a partition wall with a rather inconvenient 72mm gap...

The oval is your friend here, unless you can add a 25x50mm batten and beef the wali thickness up?

 

I've always bought from CVC Systems, who now shift boxes via Air-Haus.com, if you're looking to buy and self-install.

[Nickfromwales]

On 04/07/2025 at 14:05, Alan Ambrose said:

Nice, thanks. Assume they worked OK?

Air came out of the fresh, and left via the extract, so yes lol.

 

It was an attic room, 3rd storey up in a PH, so a fresh alone wouldn't have done much up there tbh, so I altered the design to allow fresh in and stale out, and afaic it was doing the job nicely.

 

No way to get ducts up the walls to the ceiling so went with these.

[Nickfromwales]

3 minutes ago, Nickfromwales said:

and do they have a flow rate calculator to check if multiple oval runs are required

If you speak to them (CVC) they will assist with design etc and calculate flow rates and sense check it all for you before you place an order.

 

TBH I just use my gut when sizing and numbering duct runs/type of duct/size etc, and I've been on the dot with all of the so far, as in when the systems have been commissioned downstream by CVC they have all passed with flying colours.

[Alan Ambrose]

>>> Which brand do you recommend for this

 

That bright green stuff in the image is Ubbink.

[Nickfromwales]

10 minutes ago, Alan Ambrose said:

>>> Which brand do you recommend for this

 

That bright green stuff in the image is Ubbink.

What he said...

[Stu789]

Thanks for the suggestions above.  Here is the current bungalow floor plan showing my first pass at MVHR inlet & extract points - comments/suggestions invited.

Planning to site the MVHR unit above bedroom 3 as attic trusses above non-vaulted space will provide plenty of room & its central.

I think the dining room inlet could be fed up an enlarged service void from the pantry or maybe easier is along the apex from above bedroom 3 to the dining room outlet in both cases AE35 or AE45 oval ducting reduce the space required.

[Nickfromwales]

Extracts in the wardrobes would prob need dialling down, to stop the air in the room just going a-b and missing the area at the door, and the fresh in the pantry may push the smells from stored food items into the open living area. Consider a transfer grille in the wall between the plant/utility and pantry, possibly, with the support and extract valves fitted as far apart as possible vs back to back as shown (if you go for the transfer grille).
 

Is that attic space outside the heated and airtight envelope, or do you have a full warm roof?  

[JohnMo]

I would delete the extract form bed 2 & 3 storage, there is no need. They cause air to short circuit.

 

Pantry should be an extract

 

Master bedroom supply move to near wardrobe, but do not uncut bedroom door. This gives better cross flow across room.

 

You don't really need the dining supply, move the kitchen extract to the white line between kitchen and dining area. Or better for routing may be on the kitchen side of the pantry wall

[Nickfromwales]

2 hours ago, JohnMo said:

I would delete the extract form bed 2 & 3 storage, there is no need. They cause air to short circuit.

 

Pantry should be an extract

 

Master bedroom supply move to near wardrobe, but do not uncut bedroom door. This gives better cross flow across room.

 

You don't really need the dining supply, move the kitchen extract to the white line between kitchen and dining area. Or better for routing may be on the kitchen side of the pantry wall

That’s odd, as I’d defo say the dining area was a living space so would need fresh. Would be put in a design to pass b-regs afaic. 

[JohnMo]

Through flow, use a coanda extract terminal. It's also open plan to kitchen, or is the white line a wall with no doors?

[Stu789]

2 hours ago, JohnMo said:

Through flow, use a coanda extract terminal. It's also open plan to kitchen, or is the white line a wall with no doors?

kitchen-dining room is open plan, no wall.

 

3 hours ago, JohnMo said:

Master bedroom supply move to near wardrobe, but do not uncut bedroom door. This gives better cross flow across room.

Thanks - makes sense.

 

3 hours ago, Nickfromwales said:

Extracts in the wardrobes would prob need dialling down, to stop the air in the room just going a-b and missing the area at the door, and the fresh in the pantry may push the smells from stored food items into the open living area. Consider a transfer grille in the wall between the plant/utility and pantry, possibly, with the support and extract valves fitted as far apart as possible vs back to back as shown (if you go for the transfer grille).
 

Is that attic space outside the heated and airtight envelope, or do you have a full warm roof?  

Admittedly not clear in the drawing but the storage spaces are in the corridor and are intended for potentially wet items (wheelchair, coats, golf clubs, driven by Part M wheelchair user dwelling).

For Plant & Pantry the transfer grille and S/E valves far apart sounds a good route, thanks.

The attic space is inside the airtight envelope.

[Nickfromwales]

9 hours ago, Stu789 said:

Admittedly not clear in the drawing but the storage spaces are in the corridor and are intended for potentially wet items (wheelchair, coats, golf clubs, driven by Part M wheelchair user dwelling).

For Plant & Pantry the transfer grille and S/E valves far apart sounds a good route, thanks.

The attic space is inside the airtight envelope.

Ah, sorry, I thought they were walk in wardrobes  I can see the grey lines denote the walls now, “D’oh!” 
 

Good to hear attic is ‘within’ which saves a lot of insulating/faffing about. It’s not a huge property so the unit being central

isn’t really necessary, just ‘nice’.

 

Make sure you’ve allowed for box attenuators (silencers) on the supply and extract to manage audibility; these make a good job great. 
 

Assuming you’re going out the roof for fresh and exhaust, so just make sure both roof terminals are on the same elevation.

 

If you go for the WiFi connectivity option(s), (done this previously with Brink), then you can boost from home assistant, eg just as you start cooking you can tell Alexa to boost to manage cooking smells etc.

[Nickfromwales]

@Stu789

Air-Haus.com have introductory prices on MVHR etc atm, but going up in a few weeks iirc.