FlibbleWibble

Thanks for all the responses, Looks like I will go with strap banding. Yes the unit will have attenuators straight off the bat, my noise concern was about additional noise entering the ducts from sounds transmitted into the ducting through the floorboards/supporting joists. Perhaps I've been misinformed (mis-sold!) but I understood MVHR was OK (albeit not fully effective at heat recovery) in a building built to modern building regs standards (which should achieve <5ach). The goal here is to have controlled fresh air/extract to all rooms in the house and hopefully retaining some of the warmth of the extracted air. Maybe this will be false economy over the years but I can't afford passive house standard for the house renovation (only doing a self install of the MVHR not the rest of the build).

Thanks, I hope that modern building methods will put us somewhere reasonable on the a/t but this is mostly about having controlled fresh air ventilation. Probably best not to mention the unit itself is outside the main thermal envelope…

Hi, I’m undertaking a self install of an MVHR using 90mm diameter semi-rigid ducting. The duct is not very compliant and needs strap banding a lot to hold it in position as it makes turns. Should I worry about clipping it direct to joists/underside of floorboards because of noise transmission from the rooms above? Does anyone have any good or bad experiences of how to fix semi rigid ducting and avoid any in-house noise getting into the ducts. Also the same for plenums. These I intend to install tight to the floor above which is how their side clips work but will noise come through them direct and should I consider another approach? thanks, Flibble

Thanks kandgmitchell, That is a very reassuring point about the word "internal linings"... that slipped past me. I doubt anyone could afford to line a ceiling in Zehnder plenums. I haven't seen it mentioned that anyone does it for MVHR but then someone selling ceiling speakers was adamant they need fire hoods and it got me thinking... And yes no penetration of any of the listed areas. I'll post again in the future if building control are unhappy! Thanks again, Flibblewibble

Hi, I'm doing a self-install of an MVHR (got a design done) and have suddenly got worried about Approved Document B of the Building Regs (2019 incorporating 2020 and 2022 amendments). Does anyone have any experience of this for a standard dwelling? Building regs are a challenging read... My interpretation is that there is no requirement for fire dampers or fire hoods on the vents, the dwelling in question has no floor above 4.5m and no protected stairwell is necessary. The only bit that concerns me is the general classification of lining D-s3/C-s3 and d2. I am using Zehnder plenums which have a fire protection of class E. I can't find that anyone has had an issue but things do tighten up. Anyone know the situation? Thanks, Flibble

Putting an MVHR into house refurb (not passive or air tight!) and have various questions I hope people can help me with hence joining.