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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

PLEASE NOTE: A download link for Volume 1 will be sent to you by email and Volume 2 will be sent to you by post as a book.

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    • CommentAuthorandyman99
    • CommentTimeMar 8th 2019
     
    Currently getting quotes for an MVHR system. One unit that would fit in the space I have considered is the Brink Sky Renovent. It can be mounted horizontally and can also have distribution boxes fitted directly to it. The best location would be in a small corridor that runs between 2 bedrooms. It would sit in a false ceiling and would allow all pipe runs to be as straightforward as possible, so I'm keen to fit it here. But I'm a little concerned at night time noise levels so close to the bedrooms. Assuming a well designed/balanced system running normally (i.e. non boost times) and some sound insulation in the boxing, would I hear anything, is this a sensible location?
    • CommentAuthortony
    • CommentTimeMar 8th 2019
     
    It can be turned right down at night, slow fan speeds or even right off.
    •  
      CommentAuthorDamonHD
    • CommentTimeMar 8th 2019
     
    We have a single-room MHRV unit (and HR25H) in the bathroom next to our bedroom, and although we occasionally hear it, I don't think it causes us sleep problems, etc.

    (Note: odd things happens when strong gales blow directly into it, or it ices up, but those are exceptional.)

    Rgds

    Damon
    •  
      CommentAuthordjh
    • CommentTimeMar 8th 2019
     
    Posted By: andyman99Currently getting quotes for an MVHR system. One unit that would fit in the space I have considered is the Brink Sky Renovent. It can be mounted horizontally and can also have distribution boxes fitted directly to it. The best location would be in a small corridor that runs between 2 bedrooms. It would sit in a false ceiling and would allow all pipe runs to be as straightforward as possible, so I'm keen to fit it here. But I'm a little concerned at night time noise levels so close to the bedrooms. Assuming a well designed/balanced system running normally (i.e. non boost times) and some sound insulation in the boxing, would I hear anything, is this a sensible location?

    We have a Brink Renovent Excellent 300, with Ubbink distribution boxes. It is all in a plant room that is above a bedroom. The MVHR unit is mounted on a wall and the distribution units are mounted in the floor, just above the ceiling of the bedroom. There is acoustic mat glued to the distribution boxes and acoustic rockwool surrounds them in the joist space.

    Nothing is audible at the 0 setting (50 m³/hr). There's a barely audible hiss at the 1 setting (125 m³/hr). At the 2 setting (165 m³/hr) the hiss is noticeable - similar to a hotel bedroom's air-conditioning noise. I haven't used the 3 setting (225 m³/hr) but in a quick test, the noise is noticeable but wouldn't stop me sleeping - a deeper note, more like a rumble but very steady. There's also a slight noise from other vents at the boost setting. The MVHR is audible in the bathroom on the other side of the wall it is mounted on at setting 2 or above. We normally run the system at 0 or 1 when there's just two of us in the house.
  1.  
    Aside from the acoustic issues, if you're looking at location generally you may also want to consider the duct runs in terms of heat losses.

    The recommendation in Passivhaus terms is to keep the MVHR unit as close to the outside wall/roof but still inside the thermal envelope. That way the cold intake and exhaust ducts are as short as they can possibly be, so you are minimising the heat loss through these and increasing the efficiency of the system.
    • CommentAuthorjfb
    • CommentTimeMar 8th 2019
     
    I have a brink 300 unit and I was very concerned about sound. I have might set at around a constant 120 m3/hr. in the end I have found I heard more noise from the actual ducts themselves, enough to annoy me. So I ended up building my own sound reducing box in line with the main supply duct and before the distribution box (extract is quieter for obvious reasons). Totally silent now. I was lucky enough still to have some room to fit the sound reducer in the attic (I think dimensions of one I made was around 800mm X 450mm x 350mm but you could get one/make one smaller). If possible to design in room for a sound reducer on the supply side I would.
    •  
      CommentAuthordjh
    • CommentTimeMar 8th 2019
     
    Posted By: jfbI ended up building my own sound reducing box in line with the main supply duct and before the distribution box

    We have an attenuator fitted between the MVHR unit and the supply distribution box. I think it's standard practice. The attenuator feeds into the post heater.
    • CommentAuthorjfb
    • CommentTimeMar 8th 2019
     
    It didn't seem standard practise from my supplier!
    •  
      CommentAuthordjh
    • CommentTimeMar 8th 2019
     
    Well, suppliers supply whatever you order. It's the specifier that decides what to order ...
    • CommentAuthorjfb
    • CommentTimeMar 8th 2019
     
    They were both specifier and supplier
    • CommentAuthorandyman99
    • CommentTimeMar 8th 2019
     
    Thanks everyone, really helpful responses. This position does maximise the ducting that will be within the thermal envelope - just waiting for the quote ....
    •  
      CommentAuthordjh
    • CommentTimeMar 9th 2019 edited
     
    Posted By: andyman99maximise the ducting that will be within the thermal envelope

    maximise the supply and extract ducting - good.
    maximise the intake and exhaust ducts - bad.
    • CommentAuthorandyman99
    • CommentTimeMar 9th 2019 edited
     
    Posted By: djhmaximise the supply and extract ducting - good.
    maximise the intake and exhaust ducts - bad.


    Could you explain this some more. One of my concerns was sucking intake air through the loft during the type of weather we had during the hot summer of last year and overheating the house.
    •  
      CommentAuthordjh
    • CommentTimeMar 9th 2019
     
    The air in the supply and extract ducts to and from the rooms is basically at room temperature so the heat gain from or to ducts within the thermal envelope is minimal. So their length doesn't matter.

    The air in the intake and exhaust ducts to and from the outside is basically at outside temperature, so the heat loss from the house to the ducts if they are within the thermal envelope is considerable. Even if insulated. So their length should be minimised.
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