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Housing - New Build: Insulation of MVHR ducting

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      CommentAuthorjulius
    • CommentTimeSep 21st 2009
     
    Thankyou all who helped me out with my floor insulation quandry.

    Time for the next big question!

    How best to insulate the 150mm round ducting used for my MVHR system to be??? Formed fibreglass with foil wraparound is going to cost too much (maybe £32 a metre!). Screwfix have a skinny bubble wrap foil product for £8.99 for 5m x 400mm. Possible to wrap this around and foil tape it?? Effective enough?

    Are there certain areas which are more important to insulate? (ie. cold inlet from exterior to MVHR unit/unventilated floor space runs....)

    Are there areas/runs which are best left uninsulated?

    As usual many thanks in advance, J.
    • CommentAuthorTuna
    • CommentTimeSep 21st 2009
     
    I assume from your query that you're running ducting through uninsulated loft space?
    • CommentAuthorCWatters
    • CommentTimeSep 21st 2009 edited
     
    ebay has 150mm insulated duct at £2 to £4 per meter...

    http://cgi.ebay.co.uk/6%22,-150mm-INSULATED-FLEXIBLE-DUCTING%2fVENTILATION%2fHOSE_W0QQitemZ260379369411QQcmdZViewItem

    http://cgi.ebay.co.uk/6%22,-150mm-INSULATED-FLEXIBLE-DUCTING%2fVENTILATION%2fHOSE_W0QQitemZ260341873999QQcmdZViewItem

    These are just the first I saw. You might find cheaper/better.

    Away from ebay here is insulated duct at £47 +VAT for 10 meters...
    http://www.itho.co.uk/Products/Ducting_~_Accessories/Flexible_Aluminium_Ducting/ProductsList.aspx?id=71
    so your prices seem way off.
    •  
      CommentAuthorjulius
    • CommentTimeSep 21st 2009
     
    Flexible duct increases resistance due to its inherently corrugated nature no?? I had assumed and was told to stay away from it. Thanks though..
    •  
      CommentAuthorjulius
    • CommentTimeSep 21st 2009
     
    Unless of course you wrap that around your rigid ducting. A sleeve of sorts. That might work...
    •  
      CommentAuthorjulius
    • CommentTimeSep 21st 2009
     
    Should have originally said that I was using rigid ducting. Sorry.
    •  
      CommentAuthorjulius
    • CommentTimeSep 21st 2009
     
    Have since found a fair few FG and rockwool [products so am sorted in that department. Would still like to hear about which if any pipes aren't necessary to be insulated...
    • CommentAuthorTuna
    • CommentTimeSep 21st 2009
     
    As we understand it, the air moving within the insulated envelope should all be at pretty much the same temperature, so you shouldn't need to insulate. The point is that the unit itself takes the heat out of the extract air as it leaves the building and puts it into the inlet air. So both the incoming and outgoing air should be at more or less 'house temperature'. MHVR is all about moving air around without chucking hot air out of your house, not moving particularly warm air around inside.

    The specific heat capacity of air is pretty low, so you have to move huge volumes of air around to actually warm a house. At normal ventilation levels, MHVR doesn't really move enough air to contribute to heating. You can get inline heaters that claim to do the job, but I'm quite cynical about them.
  9.  
    Lindab do a duct insulation that is suitable. Speak to Andrew Farr at the Green Building Store he'll be able to put you right - and will probably be able to provide the insulation to you also. (www.greenbuildingstore.co.uk)

    Mark
    • CommentAuthorwookey
    • CommentTimeSep 21st 2009
     
    Julius, if you could report back on what products you have found/find soon, that would be helpful to those who follow (as opposed to saying 'it's OK, I've worked it out now'). Yes, I have a vested interest in that I expect to be following soon.

    My limited understanding is that you only really need to insulate pipes in the loft or an unheated cellar. Any pipes in normal rooms should be OK as-is. Although insulated is presumably always better than not-insulated unless the whole duct route really will always be the same temp as the air inside.

    If you arrange a long input route through ground or basement then that part should be uninsulated as the idea is to warm or cool (according to time of year) the outside a ir somewhat.
    • CommentAuthorTuna
    • CommentTimeSep 21st 2009
     
    We're currently putting in the ductwork for our MHVR system - it's mainly lay-flat stuff, which folds into a rectangular section duct (approx 200 x 60mm). As specified by the system designers, none of the interior ductwork is insulated. We have short sections of insulated tube, but these are supplied purely for the inlet / outlet ducts. In those cases, the insulation is apparently as much about reducing noise as managing temperature differences.
    • CommentAuthordocmartin
    • CommentTimeSep 22nd 2009 edited
     
    Vaillant ( recoVair ) stress that insulation on the main inlet and outlet ducts to outside should be vapour impermeable. A duct conveying cold air in the heated envelope of the building will be liable to condensation.
    •  
      CommentAuthorjulius
    • CommentTimeSep 22nd 2009
     
    OK, Thanks all for your comments. I had heard about the condensation issue from exterior cold inlet also from the ducting supplier so I had planned on insulating the exterior runs - plus they go through the bedroom albeit boxed in and I need to make sure you can't hear anything.

    As I mentioned I had always assumed that flexible duct would give greater resistance to air flow (though in theory easier to run) so I decided to use rigid ducting. In particular I have chosen to use 150mm round with only a couple of sections converted to flat 220x90 (or 80 I forget- in any case the 150mm round equivalent -megaduct I think it's called). As the pipe is quite large there is a large element of boxing in and dropping sections of vaulted ceiling to get the pipe runs but as I make (or have made) built-in furniture it will all (in due course) get surrounded by cupboards, wardrobes, bookshelves and other stuff.

    Unit I've bought is Itho Eco 4 - it was a toss up between that and the Vortice Prometeo and it was almost the toss of a coin that decided it... I bought it from www.dealec.co.uk

    I have gotten my ducting from www.bes.co.uk - all next day delivery and quite competitive on price as far as I can tell.

    Insulation products I've found are rockwool pipe lagg

    http://www.aidirect.co.uk/index.php/insulation-materials/rockwool-mineral-fibre-insulation?p=2

    and knauf insulation do a FG equivalent but you'd need to call up for prices from someone like Encon.

    Sinnerboys comments throughout this forum are interesting and worthwhile I'd say. He advocates fusible link dampers on any ceiling mounted grilles/vents on lower floors and connecting the motor on the unit to the smoke alarms in that if there is a fire then the fans trip off. Seems like good common sense to me, I'm glad to have read his comments.

    Apart from that the ducting arrives today, unit on Friday so I'll drop a post once I get fitting and let you know how it goes.

    Cheers, J.
    • CommentAuthorTuna
    • CommentTimeSep 22nd 2009
     
    Sounds like you're in exactly the same position as us. We went for the Vortice unit, and they did an initial design for the installation that gave us a bill of materials for all of the items we needed to order.

    We also have a central vaulted ceiling, and have solved the issue of duct runs by putting them through the mezzanine floor and up through studwork to get to the required locations.
    •  
      CommentAuthorjulius
    • CommentTimeSep 22nd 2009
     
    Hey Tuna, Sounds like you're being a little more studious than I. I'm just doing the shortest and simplest runs possible and then working around what's left sticking out. So much else to think about it's all my brain can manage! The Vortice unit has a cool remote conrol wotsit that boosts opertaion when the co2 levels rise yes? A nice little feature that. Good luck with it. Are you installing it yourself??
    • CommentAuthorJulian
    • CommentTimeSep 22nd 2009
     
    Hi Julius
    Definitely fusible link terminal / grille for example in kitchen, plant room etc. They're well worth the cost.
    I have put runs of ducting in the loft space / roof voids hard down onto the ceiling joists (using galv. steel spiral wound 100 - 150mm duct), omitted insulation between rafters underneath and brought adjacent insualtion up to the duct. Then, as I add layers I can eventually run the insulation over the duct itself.
    Rockwool make a foil covered pre-formed mineral wool insulation but it's not cheap and hedeous stuff and besides loft insulation ought to be going in anyway.
    • CommentAuthorchuckey
    • CommentTimeSep 22nd 2009
     
    I used 4" thick polystyrene sheeting cut up into planks to make a duct of 4" square internal section for the airway. The corners were blocked to form a 45 degree bend. The bits were all glued together with brown silicone gunk bought from a market stall, 3 tubes for £1!. Its water tight (if done well) and smooth so its resistance to air flow is minimal, but it droans a bit (- organ pipe effect). For a perfect job, it should have been larger in cross section with with silencers built in it.
    Frank
    • CommentAuthorJulian
    • CommentTimeSep 22nd 2009
     
    Frank,
    that sounds like it may need tuning?
    Another option - particularly good for the duct to from machine and exterior terminals (i.e. colder air flow therefore more likely to attract condensation) is a type of rigid foam. It's similar to Climaflex type pipe insulation but a bit stiffer. You can buy bends as well as T's and of course straight duct and it's joined with plastic clips. Can't think what its called now.
  19.  
    Hi Julius,

    By quirk of fate I am doing much the same thing only a couple of weeks later. I also went for the Eco 4 from Dealec and have just found your thread, thanks for BES I've just ordered some ductwork to do the outside connections, the internal ones I was also going to convert round to flat but haven't ordered the ducting yet, need to get rid of the scaffolding asap and will do the internals later.

    What external louver/grills did you go for?

    Have you come across any 'gotchas' yet?

    A
  20.  
    Does the Eco4 do the summer bypass thingy...?

    J
  21.  
    Spec says it does, also the frosty thingy.

    A
  22.  
    The frosty thing...?

    J
    •  
      CommentAuthordjh
    • CommentTimeOct 25th 2009
     
    Posted By: juliusHave since found a fair few FG and rockwool [products so am sorted in that department. Would still like to hear about which if any pipes aren't necessary to be insulated...

    If you have a heater in the air supply then you do need to insulate those pipes even inside the heated volume. See section 3.5 in http://www.drexel-weiss.at/HP/Upload/Dateien/Kap03_Systeme_08_EN.pdf for example. Best to ask the manufacturer of your system, I guess.
    • CommentAuthorciaranw
    • CommentTimeNov 13th 2009
     
    Sorry to appear ignorant, but what are 'fusible link dampers'? I intend to install a couple of systems myself next year, so am reading all comments avidly.
  25.  
    Posted By: ciaranwSorry to appear ignorant, but what are 'fusible link dampers'? I intend to install a couple of systems myself next year, so am reading all comments avidly.


    They're controls on the ducting so that it gets closed off in the case of a fire to stop the fire spreading from room to room through the ducting. See http://www.scottaire.co.uk/circularvalves2.html for examples (no affiliate etc.)
    • CommentAuthorvEHMv
    • CommentTimeNov 13th 2009
     
    Can you share expected total install cost including the unit? Trying to get an idea of how much out of pocket I'll be if I go ahead.
    •  
      CommentAuthorBenpointer
    • CommentTimeDec 2nd 2009
     
    Hi

    On the Dealec website it says of the Itho Eco 4 "Suitable for New Build high and low rise residential buildings but NOT renovations." Given I'm doing a renovation, I just wondered if anyone knew why they say this ??
    • CommentAuthorTuna
    • CommentTimeDec 2nd 2009
     
    Posted By: BenpointerHi

    On the Dealec website it says of the Itho Eco 4 "Suitable for New Build high and low rise residential buildings but NOT renovations." Given I'm doing a renovation, I just wondered if anyone knew why they say this ??


    I think they say this because it is extremely difficult to manage air infiltration in a renovation. In such cases, the unit will not perform as designed, and will not achieve the efficiencies promised.
    •  
      CommentAuthorBenpointer
    • CommentTimeDec 3rd 2009
     
    Tuna, you must be right re Itho and refurbishment, just spotted this on Itho's (very good) website in the HRU ECO 4 page:
    Buildings suitable for HRU ECO 4 installation:
    Residential buildings
    New builds
    High and low rise buildings
    Renovations (where improvements to air tightness have been made).

    Julian, currntly trying to decide between the Itho HRU Eco 4 and the Vortice Prometeo HR 400. They look very similar (I wonder if they're the same inside -i.e. bit of badge engineering ?). The prometeo looks to have a few more features included as standard (e.g. RF controller).

    I would really love to hear from anyone who has either of these two installed...
  30.  
    The Prometeo doesn't look much like the Eco 4 I'm fitting! And according to SAP it appears to have a slightly less efficient fan at lower speeds. I think they're different. Don't know about the Prometeo, but I liked the Itho because it's been used in the Netherlands for some time, so a tested product (almost bought an AirMinder when they first appeared!).

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