MVHR Smells

[AdamSee]

I know people have mentioned in the past about the MVHR bringing in smells from outside, but what are the chances of smelling things outside that have come from the house?

 

Our retrofit project is moving along and were currently having the roof retiled with plain terracotta tiles. (approx 6" x 10"). Originally I wanted our supply and exhaust to be on the roof but finding the right vent with the correct size in a nice terracotta colour is a massive pain. So im wondering about changing them to sofit cowls but these will have to be beside our bedroom window, one either side of a bay.

 

But I remember at my last place that my kitchen extractor was fantastic at projecting the smell of what I was cooking down our road incredibly well. The last thing i want is for my neighbors to open there windows and constantly be smelling strong kitchen/bathroom smells. So what are the chances that my neighbors are going to smell what were up to? Or am I best going back to the roof idea? If i carry on with the roof vents I wont ever be able to get to them if they need servicing or cleaning.

 

 

[Onoff]

Something I've often wondered as I make by bathroom evermore airtight is how MVHR handles "natural" smells. Sod's Law the wife will bring me a cuppa in just as "somebody's" let rip. There's just nowhere for it to go and it's very noticeable. Presumably MVHR shifts this sort of thing pretty sharpish?

[vivienz]

46 minutes ago, Onoff said:

Something I've often wondered as I make by bathroom evermore airtight is how MVHR handles "natural" smells. Sod's Law the wife will bring me a cuppa in just as "somebody's" let rip. There's just nowhere for it to go and it's very noticeable. Presumably MVHR shifts this sort of thing pretty sharpish?

 

I believe that MVHR is very effective at this.  I've put my faith in it to the extent that my downstairs loo has a non-opening window.  This is because I know that one of my friends/family will open this window if they've had a bit of a struggle in there and then won't remember to close it or tell anyone it's open and completely mess up the MVHR flow.  I'll set the MVHR so that it can have a boost for 10 mins after any smelly events.

[lizzie]

23 minutes ago, vivienz said:

 

I believe that MVHR is very effective at this.  I've put my faith in it to the extent that my downstairs loo has a non-opening window.  This is because I know that one of my friends/family will open this window if they've had a bit of a struggle in there and then won't remember to close it or tell anyone it's open and completely mess up the MVHR flow.  I'll set the MVHR so that it can have a boost for 10 mins after any smelly events.

Yes it works.....tested with overnight young male guests and a hot curry. No worries at all with extracting and no return....

[Jeremy Harris]

1 hour ago, Onoff said:

Something I've often wondered as I make by bathroom evermore airtight is how MVHR handles "natural" smells. Sod's Law the wife will bring me a cuppa in just as "somebody's" let rip. There's just nowhere for it to go and it's very noticeable. Presumably MVHR shifts this sort of thing pretty sharpish?

 

 

I modified the cisterns in our bathrooms so that the air space above them connects to the MVHR extract.  The effect of this is to draw air directly from the toilet bowl to the extract, via the overflow pipe in the cistern.  It works very well at removing odours at the source, rather than having them escape into the room.  All I did was connect some waste pipe to the side of the cistern and then plumb this into the MVHR extract ducting:

 

[Russell griffiths]

Regarding your roof vents

have you thought of painting them, I had a job and could not match the old tile look, so a good rough up with sandpaper and some plastic primer and I painted them to match the old tiles, from the ground you couldn’t even pick out the vents. 

[Adam2]

@JSHarris I like your work on the WC ? Can I ask, did you also have a room extract?

[Jeremy Harris]

59 minutes ago, Adam2 said:

@JSHarris I like your work on the WC ? Can I ask, did you also have a room extract?

 

 

Yes, I fitted extracts above the shower in one bathroom and above the bath in the other, and they do most of the work in keeping the bathrooms well-ventilated, but the low flow rate extraction from the WC pan is enough to stop any odours from escaping from there.  The key to making it work well is to make sure the seat is lowered immediately after use.

[AdamSee]

JSHarris, I've heard of your toilet idea in the past and I must say that I'm a big fan of it, surprisingly I can't convince the other half that it's a good idea. I have seen that Geberit have copied your ideas on the their monolith toilet frames a just added in a carbon filter. 

 

From everyone's answers,  I now have two questions to ask myself, one is do I buy the horrible colour red vents and repaint them to match the terracotta tiles or risk putting a extra duct near my neibours window and hope the've lost their sense of smell.

 

Like everything it's going to be determined by available time. Dam.

[Adam2]

@JSHarris OK thanks, so with the WC extract do you connect into the room extraction or run a separate duct to the manifold? I assume the former. Presumably all the water must empty the tank and at that point the air can be withdrawn from the bowl? Or am I missing something?

Thanks

Edited October 19, 2018 by Adam2

[Declan52]

10 minutes ago, AdamSee said:

JSHarris, I've heard of your toilet idea in the past and I must say that I'm a big fan of it, surprisingly I can't convince the other half that it's a good idea. I have seen that Geberit have copied your ideas on the their monolith toilet frames a just added in a carbon filter. 

 

From everyone's answers,  I now have two questions to ask myself, one is do I buy the horrible colour red vents and repaint them to match the terracotta tiles or risk putting a extra duct near my neibours window and hope the've lost their sense of smell.

 

Like everything it's going to be determined by available time. Dam.

Have you contacted the  manufacturer of your tiles to see if they do a vent tile??

[Jeremy Harris]

8 minutes ago, Adam2 said:

@JSHarris OK thanks, so with the WC extract do you connect into the room extraction or run a separate duct to the manifold? I assume the former. Presumably all the water must empty the tank and at that point the air can be withdrawn from the bowl? Or am I missing something?

Thanks

 

Our bathrooms are next to each other, and there was an area behind the bathroom walls where I could run an extra duct to the manifold, so that's what I did.

 

The pan extract runs all the time, as there is an always-open air way from the space above the water in the cistern to the pan rim flush outlets, via the overflow pipe.  This means there's a gentle extract from the pan 24/7.

[AdamSee]

43 minutes ago, Declan52 said:

Have you contacted the  manufacturer of your tiles to see if they do a vent tile??

 

Err......no....didn't think about that.....back to the Google.

 

Update, right,I had found a decent match from several different manufacturers already but the max free air space of one vent is 7500mm. And Im unsure as to weather these would be suitable for air intakes. I guess I could use two for a exhaust so that any smells exiting the house leave via the top of the roof, at a combined 15,000mm it's certainly better.

Edited October 19, 2018 by AdamSee

[Onoff]

I've also gone down the route of modifying a Geberit wall mount cistern to incorporate pan extract:

 

Solvent weld boss:

 

 

Drilled a hole and Sika Flex EBT'd:

 

 

 

Solvent weld pipe taken up through the stud wall into the loft. Not connected to anything yet!

 

 

 

All buried in foam:

 

 

 

[AdamSee]

Onoff, this is brilliant, what's the plan for connecting what i assume is 40mm pipe up to your ducting system? 

 

I'm sure I could sneak this in without the wife noticing. 

[Roundtuit]

I very much admire the ingenuity of a pan extract, but is your ar$e really going to maintain a seal long enough to prevent odour escape into the wider room?  Even if you put the seat down afterwards, I'd assume the source of the smell is flushed and gone?

 

As regards neighbours experiencing your cooking smells (before and after!), mvhr is surely no different to any room extractor, or opening a window?  Vent where suits you best; presumably you won't need to open your bedroom widow other than to perhaps purge on a warm day, or there is limited benefit to mvhr, and it looks like you have plenty of airspace around your house to allow for natural dispersal.

[Onoff]

7 minutes ago, AdamSee said:

Onoff, this is brilliant, what's the plan for connecting what i assume is 40mm pipe up to your ducting system? 

 

I'm sure I could sneak this in without the wife noticing. 

 

It's 32mm pipe. An earlier thread discusses a bit more here:

 

 

I have no extract system anywhere in the house at the mo. Current thinking is a small in line fan. How it's triggered, via bathroom lighting, manual switch, occupancy sensor etc is tba. 

[PeterW]

1 hour ago, AdamSee said:

but the max free air space of one vent is 7500mm.

 

That isn’t a real issue as 7500mm2 is around the same as a 97mm diameter pipe. All that you would find is an increase in velocity (and potential noise) from the vent but it wouldn’t be a lot. 

 

Have a look at Timloc for decent roof vents in pretty much all roof tile profiles. 

[AdamSee]

9 minutes ago, Roundtuit said:

I very much admire the ingenuity of a pan extract, but is your ar$e really going to maintain a seal long enough to prevent odour escape into the wider room?  Even if you put the seat down afterwards, I'd assume the source of the smell is flushed and gone?

 

As regards neighbours experiencing your cooking smells (before and after!), mvhr is surely no different to any room extractor, or opening a window?  Vent where suits you best; presumably you won't need to open your bedroom widow other than to perhaps purge on a warm day, or there is limited benefit to mvhr, and it looks like you have plenty of airspace around your house to allow for natural dispersal.

 

I would be surprised if this didn't work regardless of how well you butt seals the toilet seat as your just changing the direction of air flow, our main bathroom is a jack and jill type, so anything that can help really is a help, but at the end of the day the supply vent In the bedroom should keep air flowing in the right direction to manage it. Frankly, I'm just a fan of overkill and over engineering. 

 

Granted mvhr is no different to any extractor, it's just that my original idea of venting through the roof ment that any of my concerns about smells would be vented in a place thats not near any possible windows. But I guess at the end of the day, anyone who's got a external venting kitchen extractor isn't worying about these sort of things. Just a unnessecary worry that I have.