Andeh

This is pretty much what we are doing!

Thanks Nick, appreciate the thoughts & given me something to think about. I was intending to double up on the insulation on the ducting internally anyway (and did so on the wall mounted ducting for our 2nd MVHR), however following your point out, I will triple layer it to try and improve as best I can!

Hi Dean, you and I are obviously kindred spirits! I went through all of this last week, as the thought of cutting through the roof had me in cold sweats & sleepless nights, but we had no option of sideways venting. MVHR supplier/fitter let me down due to a miss communication between him & builder, and I saved £3k doing it myself vs going through builder's normal supplier...so I own the job/risk, having never done this before. Hence belt, braces & everything on top. Space was also an absolute bastard, and slanting roof, and awkward joists/wall config meant I risked having a low point in my ducts for any water to settle into. I used the below onto the joints I made, and then again on the roof whilst we wait for the roofers to come back to make the 'sleeve' as the final covering. A very wet weekend showed no leaks, and some close up investigation of it showed it to be very robust & confidence inspiring at preventing water ingress. Ill smudge on a second coating for good measure later on down the line, but even as a ''temporary'' solution, its great stuff! https://www.amazon.co.uk/Everbuild-EB25-Ultimate-Adhesive-Cartridge/dp/B07T76J481/ref=sr_1_1_sspa?crid=OQXA6AYBIWBC&keywords=Everbuild%2BEB25%2BGrey&qid=1673276197&s=industrial&sprefix=everbuild%2Beb25%2Bgrey%2Cindustrial%2C70&sr=1-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1 Notes: 1) Yes I know they aren't dead straight, they look(ed) fine in person until I noticed them in that photo!! fecking spirit level broke on me (joys of working on the roof) and I should have ceased work until i got a new one, tired, stressed & fed up of worrying about it...oh well! 2) The duct lids are pushed far down, as they need trimming down & adjusting before commissioning in another couple of months. Ill let them sleeve them, then trim to 150mm off the roof and secure them properly once done. 3) ill be finishing off insulating it tomorrow & trying to tidy it up a bit. (ignore what looks like a split, that's an odd hair/branch thingy making it look like its split..... Its all 100% smooth sealed)

But then its a 20 year life span for a deep sea wind turbine according to Google, which are full of complex multi material composite components with no recyclablility at all, that are miles offshore. OK its not nuclear waste (quality of headache) but there are 100x more of then (quantity of headache). When these wind turbines need decommissioning I'm confident they will cause more 'environmental harm' then the equivalent nuclear waste per MW.... Until cheap energy storage becomes available, no energy source has the answer, and a mixture is required... Nuclear though has the reliability, robustness and longevity more then any other 'minimum baseload' generation sources.

We considered one for a very short amount of time... Then went down the A2A route. Just because massively improved performance for a reasonable (but not massive) cost in the rooms where it mattered. Rest of the house will be fans and ASHP cooling.

Thanks john! That sounds fair

Thanks very much all! I am leaning towards just leaving it more & more. Out of curiosity, does it come with any WIFI monitoring adjustments?

I have an enthusiastic amateur attempt, but we are mid build. Basically check 2 to 3 times a week with expanding foam and silicone.... And look for every nook and cranny internally and externally which could allow air to pass through. Then a Liberal amount of expanding foam, then silicone over the top of it when dry.

Just in case, I was warned by plumber copper pipes degrade in (acidic?) expanding foam... So ensure no exposed copper pipes are there!!

Left out filter or didn't close filter door? Car flap open?

Did you ever get to the bottom of this tomaus?

Aaaah, expanding foam.... my second true love these days!! At times 1st true love..

Thanks, frustratingly I have managed to route it....there is just so little space to insulate it & seal each joint (roof vents & worried about water ingress) that I want to test other options before I doom myself to kissing goodbye to the skin on my knuckles! I have ordered a length of the above to test it, so fingers crossed!

Thanks both. Would the below be suitable? I think 1.5m would do me length wise! https://www.amazon.co.uk/125mm-1-5m-Aluminium-Ducting-Hose/dp/B09LZXD82Y/ref=sr_1_3?crid=30E7ELZ0O4UXD&keywords=Aluminium+Air+Ducting+125&qid=1672678764&refinements=p_76%3A419158031&rnid=419157031&rps=1&s=diy&sprefix=aluminium+air+ducting+125%2Cdiy%2C1049&sr=1-3

I have a really awkward run to get my inlet and outlet pipes through to the ceiling. Metal rigid Ducting is killing me, trying to find a routing! Lost several hours and still struggling. Is there an equiv to the 125mm smooth bore Ducting the installer used to connect the MVHR to the rooms. Due to a poor installer letting me down, I'm stuck trying to resolve this myself! Thanks in advance.

Thanks all! The manual does talk about an optional extra 'wired remote control' which has the same functions as the main unit it says. I believe this is the same unit we are having fitted in all the bathrooms/kitchens to enable a manual boost. However I do want to seek an existing owners help in determining whether it can be used to turn the unit off, or indeed set it to holiday mode. Totally appreciate the comments on leaving running, and they normally would be, but if we are away for a few weeks I would like the option of switching the units off/holiday mode, as I would do for network switch & other background load power draws. When we get home, i'd just run a purge cycle and crack on as normal. Lots of small things do start to add up, and I am looking at our current rental's background electricity draw of 75 - 150w and cant help but think 100w for MVHR (as said above), ?50W for network, ?watts for CCTV, ?watts for alarm, ?watts for WIFi hotspots, ?watts for extra fridge freezer etc etc.....will all start to add up to a very meaty background load!!

I would think several large 40mm+ concrete paving slabs under various structural points would be plenty to share the load. Ensure all are level using a biscuit mix of concrete/sand to help as well.

We will have 2 x MVHR when we move in, which we are approx 3 months away from. We will regularly spend a few nights away from home & I am fixated on trying to keep energy costs down. One MVHR will be in our loft space, with boost switches in each of the bathrooms to manually boost it. Another in a cupboard - nether easily accessible for a quick 'switch off on the way out the door'. Can anyone with Vent Axia MVHR's talk me through the control option's for them? ie: 1) Can I use any one of the ''boost switches' to simply turn the whole unit off? 2) Can I/do they allow WIFI control so I can do it via my mobile? 3) Is there a way to remotely install (do i need to hard wire a cable now?) a control panel to enable me to switch off the units without going into the loft? Many thanks,

Thank you for coming back and confirming this, well done for resolving it!!

Yeah, I really wanted a single big unit for the power usage reduction, but house design just blocked it outright. Was a none starter unfortunately. I have done my best to ensure a gradiant through the pipework down into the MVHR, and the vents have large overhangs to help limit driving rain getting in. Is 1.2m separation OK on external vents? Manual doesn't recommend anything and I figure with the unit likely to stay on 20%, nearly 2x over sized, and an above average windy location will ensure no cross contamination!

We had a company out who designed & installed our 2 x MVHR. We had to have two due to an middle entrance hallway separating two ''wing'' of the house preventing pipework. The smaller unit is a Vent Axial Kinetic B....the installer didn't install the inlet & outlet rigid ducts due to not knowing where we were going to punch through the flat roof above the units location. As a result I have been installing the inlet/outlet ducting myself having worked out where. However, no where in the manual does it state dos/don'ts nor requirements for the inlet/outlet ducting, and due to the Christmas hols the installer is offline to guide me, but I need to get it all done due to the plaster boarding starting when we get back. I have used 125mm rigid ducting, have installed the ducting so that the externals are 1.2m apart in the roof & done my best to ensure there are no 'low spots' for moisture to pool. I will double wrap them in insulation, just because I have that quantity. I will wrap each joint in aluminium foil tape to ensure it is secure. is there anything else I need to be aware of, before I secure it all together & wrap in insulation? Thanks, Unit: Lo-Carbon Sentinel Kinetic BH | Vent-Axia# Manual: https://www.vent-axia.com/file/196379/download?token=EZMXaPT-

Afraid I can't help much other then to say Bravo, there's some serious history in those ASHP!! 😨 Are you able to add any more insulation anywhere in the house? As with laptops & mobile phones, what was high end 10 years ago has sadly moved on now, insulation standards being no different.

I wish!!

Thanks all, I can do that worse case, just trying to avoid the cost if I can help it. Pictures might help.... We have had 3 of these mezzanines/galleries built. using 220mm x 45mm joists joined together to form a 220 x 90mm master beam. This has left us with a lip, that is a trip hazard near the staircase we will install. As a result, I want them to trim this lip down, and add a third sistered joist to form the ultimate 150mm x 135mm master beam. Online span calculations show that for a joist of 72mm x 145mm will pass a room width of up to 3.4m at medium loading (400mm joist spacing, as ours are). With our desired joist being 150 x 135mm, this should far exceed the minimums, surely?# Free UK Span Table for Domestic Floor Joists to BS 5268-7.1 (C16, 1.5 kN/m² load) - Timber Beam Calculator [img]https://i.imgur.com/KfWZnfZ.jpg[/img] [img]https://i.imgur.com/IWyJYjk.jpg[/img]

Please post the results of your investigation. We're in a rental new build, 2019 build, EPC 86, airtightness of 3.5 "as tested". The fact I have gone round and sealed up the drafts (incl a tea towel in the Extractor fan it got so bad...) lead me to believe they bullshited the test. Rest of the house and windows bleed heat at an appalling rate as well as well, I'm furious on principle... Even if I don't own the place I'm disappointed in it.