sonicboom Posted December 9 Share Posted December 9 Has anyone fitted any dMVHRs ? are they any good ? I have a room that is too far out for MVHR so dMVHR is probably the most conducive solution, however, the efficiencies aren't very pleasing. I have seen PRANA claiming 96% efficiency but I don't know how that scales as the temps drop. Link to comment Share on other sites More sharing options...
JohnMo Posted December 9 Share Posted December 9 why not use something like this - other makes are available https://www.ventilationland.co.uk/en_GB/p/brink-indoor-mixfan-co2-controlled-up-to-70-m3-h/17927/ You use the MVHR to dump air in to the hallway instead of the room directly. This fan is installed above the doorway or in wall and sucks air from room based on humidity and/or CO2 levels. Air is drawn into room via door undercut. Link to comment Share on other sites More sharing options...
sonicboom Posted December 9 Author Share Posted December 9 11 hours ago, JohnMo said: why not use something like this - other makes are available https://www.ventilationland.co.uk/en_GB/p/brink-indoor-mixfan-co2-controlled-up-to-70-m3-h/17927/ You use the MVHR to dump air in to the hallway instead of the room directly. This fan is installed above the doorway or in wall and sucks air from room based on humidity and/or CO2 levels. Air is drawn into room via door undercut. Thanks. It would work very well in a bedroom but the problem room is in fact the kitchen and I am not sure if it'll work as effectively since moisture is the bigger issue. Link to comment Share on other sites More sharing options...
JohnMo Posted December 9 Share Posted December 9 44 minutes ago, sonicboom said: problem room is in fact the kitchen No wouldn't work. Trouble is without extracting to the main MVHR you don't have a well balanced system, so not that much energy to recover. So assume not on a new build? If your not super airtight (you may be) MVHR is pretty much a waste of time and you are better with on demand dMEV. Link to comment Share on other sites More sharing options...
sonicboom Posted December 9 Author Share Posted December 9 (edited) 1 hour ago, JohnMo said: No wouldn't work. Trouble is without extracting to the main MVHR you don't have a well balanced system, so not that much energy to recover. So assume not on a new build? If your not super airtight (you may be) MVHR is pretty much a waste of time and you are better with on demand dMEV. It's a 1960s build, and the property is extremely airtight in prep for mvhr. So there is no way around it then? Edited December 9 by sonicboom Link to comment Share on other sites More sharing options...
Mike Posted December 9 Share Posted December 9 22 hours ago, sonicboom said: I have a room that is too far out for MVHR Too far out? What's the problem? Link to comment Share on other sites More sharing options...
sonicboom Posted December 9 Author Share Posted December 9 12 minutes ago, Mike said: Too far out? What's the problem? Its a single story extension with no way of access through the joists so would need to go out externally about 3-5m. I am not too keen on that - primarily aesthetics. Link to comment Share on other sites More sharing options...
Mike Posted December 9 Share Posted December 9 25 minutes ago, sonicboom said: Its a single story extension with no way of access through the joists Then maybe 25mm x 225mm rectangular ducting at ceiling level would be acceptable? If you don't like the aesthetics of boxing it in, you could drop the entire ceiling by 25mm, unless you have very restricted headroom. Link to comment Share on other sites More sharing options...
JohnMo Posted December 10 Share Posted December 10 Post a drawing of your extension/house Link to comment Share on other sites More sharing options...
sonicboom Posted December 12 Author Share Posted December 12 On 09/12/2024 at 23:32, Mike said: Then maybe 25mm x 225mm rectangular ducting at ceiling level would be acceptable? If you don't like the aesthetics of boxing it in, you could drop the entire ceiling by 25mm, unless you have very restricted headroom. Can you recommend rectangular ducting - this might work. Does it need to be 225mm though ? Link to comment Share on other sites More sharing options...
JohnMo Posted December 12 Share Posted December 12 3 hours ago, sonicboom said: Can you recommend rectangular ducting - this might work. Does it need to be 225mm though ? Blauberg? Just about any ventilation supplier. Link to comment Share on other sites More sharing options...
Mike Posted December 12 Share Posted December 12 7 hours ago, JohnMo said: 11 hours ago, sonicboom said: Can you recommend rectangular ducting - this might work. Does it need to be 225mm though ? Blauberg? Just about any ventilation supplier. Yes, not difficult to find. Manrose and Polyvent are two brands, but there must be others. I've seen them squarer (but deeper) sizes, but 25 x 225mm is the thinnest I've come across. Link to comment Share on other sites More sharing options...
sonicboom Posted December 12 Author Share Posted December 12 Thanks guys. What about insulation of this form factor? the insualtion makes up the bulk of the size i.e. 50mm, so it still amounts to 125mm. Link to comment Share on other sites More sharing options...
Mike Posted December 12 Share Posted December 12 1 hour ago, sonicboom said: What about insulation of this form factor? If this duct is running from the MVHR unit (or a manifold) to or from a ceiling terminal, and if the duct is on the warm side of the ceiling insulation, they you don't need to insulate the duct. Link to comment Share on other sites More sharing options...
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