Demand Controlled Ventilation

booooonzo

Has anyone ever used slate vents piped to a ceiling vent grille instead of trickle or wall vents combined with a DCV extract unit?

I spoke with an installer who said they have done it when noise might be an issue and the wall vents even with the sound kit allow more noise in.

I have 2 road facing bedrooms and I would like to keep them fresh but without introducing any more noise.

He reckons the extract is more important than a humidity controlled inlet and a slate vent inlet with insulated pipe will be sufficient for air and low noise (slate vents at rear of house.

Seems like a good idea to me but I've not come across it.

any potential downsides?

My plan is upstairs only first with 2 wet rooms and 4 bedrooms and venting out via Slate vent also due to hipped roof.

thanks

Lumen

I think you're describing Passive Stack ventilation.

https://www.greentherm.ie/introduction-to-the-different-types-of-ventilation/

Calahonda52

https://cdn2.hubspot.net/hubfs/6540340/Partel%20-%20Ventilation%20Solutions%20for%20Energy-Efficient%20Buildings.mp4

is a recent presentation on ventilation by Partel

Yellow_Fern

booooonzo wrote: »

Has anyone ever used slate vents piped to a ceiling vent grille instead of trickle or wall vents combined with a DCV extract unit?

I spoke with an installer who said they have done it when noise might be an issue and the wall vents even with the sound kit allow more noise in.

I have 2 road facing bedrooms and I would like to keep them fresh but without introducing any more noise.

He reckons the extract is more important than a humidity controlled inlet and a slate vent inlet with insulated pipe will be sufficient for air and low noise (slate vents at rear of house.

Seems like a good idea to me but I've not come across it.

any potential downsides?

My plan is upstairs only first with 2 wet rooms and 4 bedrooms and venting out via Slate vent also due to hipped roof.

thanks

that is an interesting question. Do you think you can get the duct to reach the garden facing roof slope? I think if you can, you might be onto something.

BryanF

Yes there are slate vents. Be clear fill correct free area is selected and ensure they used ridged ductwork. Be clear where you put the unit there is a small amount of noise of the extract unit fan

booooonzo

Lumen wrote: »

I think you're describing Passive Stack ventilation.

https://www.greentherm.ie/introduction-to-the-different-types-of-ventilation/

I don't think so. this will have mechanical demand controlled extract fans

booooonzo

Calahonda52 wrote: »

https://cdn2.hubspot.net/hubfs/6540340/Partel%20-%20Ventilation%20Solutions%20for%20Energy-Efficient%20Buildings.mp4

is a recent presentation on ventilation by Partel

very good thank you. I just watched and its quite informative.
Might give them a shout too although their de centralized system appears quite expensive

booooonzo

Yellow_Fern wrote: »

that is an interesting question. Do you think you can get the duct to reach the garden facing roof slope? I think if you can, you might be onto something.

Yip, should reach the rear facing slope where the sound would be a lot less.

booooonzo

BryanF wrote: »

Yes there are slate vents. Be clear fill correct free area is selected and ensure they used ridged ductwork. Be clear where you put the unit there is a small amount of noise of the extract unit fan

The free area on my slate vents i am pretty sure is 10kmm2 which is not ideal for extract as far as i know, I think 15k would be more desirable.
Might have to go over wall plate and out soffit if the room is there over the plate.

Will look to find a way to decouple the unit in the attic as much as possible alright.

Lumen

booooonzo wrote: »

I don't think so. this will have mechanical demand controlled extract fans

Ah right. I read your post as

Has anyone ever used
(slate vents piped to a ceiling vent grille)
instead of
(trickle or wall vents combined with a DCV extract unit)
?

Rather than

Has anyone ever used
(slate vents piped to a ceiling vent grille)
instead of
(trickle or wall vents)
combined with a DCV extract unit
?

Calahonda52

booooonzo wrote: »

very good thank you. I just watched and its quite informative.
Might give them a shout too although their de centralized system appears quite expensive

Yes they are and they acknowledge that, in part by saying that a lot of the 4/5 k MHRV systems here are not actually doing the job.
That is a view I would share.

Having said that DCV Decenrtralised MHVR seems to be the way to go, look at the % in Germany, especially when you look at the cost over 30 years

IIRC they said one the fans they have is 0.3 watts, maybe I need to go to specsavers

thebackbar

Calahonda52 wrote: »

Yes they are and they acknowledge that, in part by saying that a lot of the 4/5 k MHRV systems here are not actually doing the job.
That is a view I would share.

Having said that DCV seems to be the way to go, look at the % in Germany, especially when you look at the cost over 30 years

IIRC they said one the fans they have is 0.3 watts, maybe I need to go to specsavers

Is there an official source for these figures from Germany ? If you look at the German self build forums the reports around lunos aren't glowing by any means.

DCV runs into big problems when the vents are facing into a prevailing wind, the fans get over run by the wind and you have cold air blowing into your house.

Lumen

thebackbar wrote: »

DCV runs into big problems when the vents are facing into a prevailing wind, the fans get over run by the wind and you have cold air blowing into your house.

Is that solvable with a backdraught damper?

Outkast_IRE

Lumen wrote: »

Is that solvable with a backdraught damper?

No as the wind is pushing into the house the same direction your fresh air is coming in within this scenario.

If it was an extract vent, then yes.

Lumen

Outkast_IRE wrote: »

No as the wind is pushing into the house the same direction your fresh air is coming in within this scenario.

If it was an extract vent, then yes.

Ah, on the inlets, gotcha.

Aereco do an inlet with an "automatic airflow controller" and claim:

The ACW makes it possible to limit the maximum airflow to 40 m3/h in a duct 100 or 125 mm in diameter, even when the pressure exceeds 20 Pa (when there is wind for example).

https://www.aereco.com/products/air-inlets/eht/

I dimly remember from when I was researching this before that effective open area is a bit less with the controller fitted, but I guess it's all in there somewhere.

thebackbar

Outkast_IRE wrote: »

No as the wind is pushing into the house the same direction your fresh air is coming in within this scenario.

If it was an extract vent, then yes.

With the lunos e2 the vent cycles between being an inlet and an extract vent. 90 seconds one direction then 90 seconds the other direction.

Outkast_IRE

thebackbar wrote: »

With the lunos e2 the vent cycles between being an inlet and an extract vent. 90 seconds one direction then 90 seconds the other direction.

I am actually a consultant building services engineer who designs and specifies ventilation systems for all types of buildings.



Looking at the Lunos e2 running at low speed i.e the quietest setting which will be most peoples preference it delivers

17m3/h = 4.7l/s - This quantity of air as far as im concerned is woefully inadequate to maintain good air quality for one person never mind in a family room or bedroom with 2 adults sleeping.



Lets say we use it at the highest setting

38m3/h = 10.5l/s - Just adequate for good air quality with one adult. its also 26db at this speed so its an audible background noise at this stage, no doubt for most people unless very rural their background noise is above this level.



Overall to be honest with you most Irish homes have woefully inadequate fresh air as it is, due to people closing vents, blocking vents , no vents , not purging air by opening windows each day etc. In my opinion one of these Lunos e2 in each room would be woefully inadequate on its own, to maintain good air quality you would need a window open also, which would defeat the benefit of the heat recovery.



With everything we know about air quality and its relationship with conditions such as Asthma, mould alergies and buildup in homes and now Covid 19 etc. you can trust me that demand controlled systems are not going to be the ideal solution for a long time to come, all the research is pointing to the more fresh air the better, the more constant the better.

Calahonda52

Outkast:
Useful post:
what do you mean by no doubt for most people?
.
Trust is earned not granted.

booooonzo

Outkast_IRE wrote: »

I am actually a consultant building services engineer who designs and specifies ventilation systems for all types of buildings.



Looking at the Lunos e2 running at low speed i.e the quietest setting which will be most peoples preference it delivers

17m3/h = 4.7l/s - This quantity of air as far as im concerned is woefully inadequate to maintain good air quality for one person never mind in a family room or bedroom with 2 adults sleeping.



Lets say we use it at the highest setting

38m3/h = 10.5l/s - Just adequate for good air quality with one adult. its also 26db at this speed so its an audible background noise at this stage, no doubt for most people unless very rural their background noise is above this level.



Overall to be honest with you most Irish homes have woefully inadequate fresh air as it is, due to people closing vents, blocking vents , no vents , not purging air by opening windows each day etc. In my opinion one of these Lunos e2 in each room would be woefully inadequate on its own, to maintain good air quality you would need a window open also, which would defeat the benefit of the heat recovery.



With everything we know about air quality and its relationship with conditions such as Asthma, mould alergies and buildup in homes and now Covid 19 etc. you can trust me that demand controlled systems are not going to be the ideal solution for a long time to come, all the research is pointing to the more fresh air the better, the more constant the better.

Interesting reading,
What would you think of the V4A from aereco? (https://www.aereco.com/products/exhaust-fans/v4a-premium/#characteristics)

specs say 210m3/h max and that would be servicing 2 wet rooms in my case and 4 bedrooms (2 adults occupancy atm) with open ceiling (non humidity controlled) inlets piped from slate vents on a fairly sheltered side of the house

probably hard to say without actually looking but am i in the ballpark for a someone decent budget system?

thanks

Outkast_IRE

Calahonda52 wrote: »

Outkast:
Useful post:
what do you mean by no doubt for most people?
.
Trust is earned not granted.

Just in relation to the acoustics and whether you will actually pick on the noise of the fan at higher speeds. Acoustics is a funny area, in that the individuals perception can play into it so much. Having lived under an airport flight path growing up i would be well used to some level of background noise, others may not.



If your living very rural then there can be very little background noise, so even a quiet fan running could be noticed potentially, partly because the occupants are used to the relative silence.



Whereas in a city or suburban location there is a higher level of background noise at all times due to car movements, pedestrians, so people are less likely to pick up on the quiet fan.

Outkast_IRE

booooonzo wrote: »

Interesting reading,
What would you think of the V4A from aereco? (https://www.aereco.com/products/exhaust-fans/v4a-premium/#characteristics)

specs say 210m3/h max and that would be servicing 2 wet rooms in my case and 4 bedrooms (2 adults occupancy atm) with open ceiling (non humidity controlled) inlets piped from slate vents on a fairly sheltered side of the house

probably hard to say without actually looking but am i in the ballpark for a someone decent budget system?

thanks

The sort of airflow rates you should be getting are in TGD F so you can have a look at the calcs they are straightforward enough, but just remember these are minimum requirements.



Retrofit scenario ?



On the whole i am not a big fan of dedicated mechanical extract ventilation systems. Alot of their energy efficiency claims are based on it being demand based which as i mentioned previously i am not too keen on. Its a big step back from MHRV which really is more energy efficient.

If i was in an existing build with any condensation or ventilation issues, i think personally i would lean towards positive input ventilation, and get good quality fans in each WC/Bathroom that are sized correctly, with a 15min run on and a backdraft damper.

If money was no object and i had the space and routes then MHRV comes out on top.

Calahonda52

One aspect that has not been aired much in this arena is the importance of:
1: establishing where u are on the radon map of Ireland.
2: if in an area of high radon, then really careful attention need to be paid to the radon barrier and ventilation of the sump if that is the design solution

I have some stuff on it, will dig it out.

Charlie 08

I've been quoted 2600e for MEV system (3 bathroom/kitchen/utility) Seems expensive given a similar brand can be bought in NI for 1000e. My DIY skills aren't up to the challenge. Is it worth sourcing someone to do the install or would it work out just as expensive?

Outkast_IRE

Charlie 08 wrote: »

I've been quoted 2600e for MEV system (3 bathroom/kitchen/utility) Seems expensive given a similar brand can be bought in NI for 1000e. My DIY skills aren't up to the challenge. Is it worth sourcing someone to do the install or would it work out just as expensive?

Is the 2600 quote with install ?

Charlie 08

Outkast_IRE wrote: »

Is the 2600 quote with install ?

Yes, its demand controlled with boost switches.

Outkast_IRE

Charlie 08 wrote: »

Yes, its demand controlled with boost switches.

I would imagine there is a few days works between, the install, electrical works and commissioning. The price is in the ballpark of where i would expect but as always in these situations get a 2nd price from another reputable company.



If you supply the parts and any of them break and installer will have nothing to do with you. If you get it all from a reputable company if there are any issues down the line they should help you.

Charlie 08

Some good points and advice there.
Thanks