Tight space squeeze too ambitious?

[tanneja]

Some may recall I have asked questions on MVHR before, it is now at the stage of ordering, and while I had thought I was in a good position, having read historic posts I have doubt as to whether I have provisioned enough space for every element.

 

Below (MVHR ducting plan (ground floor).jpg) is the planned layout of the utility section.  We have a generous airing cupboard for non-tumble clothes items with an MVHR cupboard next to it. The grey grid on the pics is 1m2.  The airing cupboard doesn't need to be a full 1000mm deep but would be nice to replicate the kind of drying volume you get with an Xframe clothes horse.

 

 

The plan was to have a full height (2.4m) by 1m wide cupboard where the MVHR unit was placed near the ground (concrete floor, and the wall there is masonry, high enough off the ground for unit drainage, hoped for around 150mm to be sufficient).  Then I found the Ubbink 24 duct manifolds which seemed like it would give be the option of runs to the left and right and upwards, with a mains duct connection to the MVHR unit coming from below.  This felt like I could mount them still within that space, connected to the MVHR unit via 500mm long flexible silencers.  I hadn't given lots of thought to the position of the external intake and exhaust vents, nor how this arrangement of distribution boxes would mean no access to the one behind (the Ubbink has distribution box based restrictor rings that can be used to balance the system, but given the lack of access, I presume we would need to go with valve based balancing on whichever unit is behind, unless they are sympathetically overlapped somehow).

 

To make life more interesting, after reading various posts, I would ideally like to pre-filter the intake with a modest wall mounted filter box between the external intake vent and the MVHR, and likewise for the external vent, as we have copious numbers of flys, wasps and bugs that roost in any opening they are given (+10 wasp nests discovered during the renovation). 

 

Now seeing that most of the unit options have the external intake / exhaust on one side of the unit (I had assumed there were models where they would be the back two ports on the unit), and knowing that meeting the typically advised space between external vents will be challenging, I'm wondering out aloud what my best option is.  Below (MVHR Cupboard.jpg) is the front view of the utility run. To this layman, the two lowest space sacrifice options for external vents seemingly are pairs "A" or "B", distanced 1.5m and 1m between themselves respectively, with "A" requiring sacrificing some depth to the airing cupboard.

 

 

Obviously there are all kinds of alternatives we could explore, like pulling the full utility bank (washer, dryer, sink) off the wall to make space for one of the external ducts to run behind it, or taking one of the external vents up to the first floor. I have shown here what is currently on the first floor for your guide (MVHR options on the first floor.jpg), with the MVHR / airing cupboards ghosted on to have a feel for their relative position.  I am guessing we would be taking about a boxed section in the most southerly shower room near the slim window.

 

 

I also include the side elevation to for clarity (Side Elevation.jpg), the window by the utility area is "11".

 

 

This is all in addition to not knowing what unit we should go for.  I believe I know what control method we want (ideally be able to plug in a Cat5/6 cable and bring back to the home hub for future tinkering), and we have approximated the required size given our property volume (500m3) with assistance from BPC, but the unit choice seems irrelevant if we can't fit all external and radial ducting in.  Perhaps an MVHR unit with interchangeable top and side duct entry points (such as the VentAxia Kinetic PlusB) makes this ludicrously tight fit somehow possible, if coupled with the collective brainwaves of some experienced MVHR self installers  

 

After reading what feels like hundreds of personal accounts and discussions, I do have more questions regarding:

• the unit choice,
• the vent types,
• the possibility / benefit of hooking other appliances (toilet / tumble) to extracts,
• the relative effectiveness of different silencers (rigid vs flexible),

...but I am probably pushing my luck already with hoping anyone can solve my space issues in an elegant way.

 

Could anyone offer any advice as to what will likely be achievable in the real world?  It will be the first ever install for me and my enthusiastic main builder.

 

Edited January 3, 2021 by tanneja

[Ferdinand]

The detail of MVHR is not my knowledge area, but contingency planning may be slightly.

 

I think the large airing cupboard provides you with a space reserve, into which you can expand if you find you need more space for the MVHR.

 

If the airing cupboard is for drying not storing linen and clothes, then you have a Plan B available in the form of eg a Pulley Maid in the body of the utility area, which is what a lot here do and find it very satisfactory. 

 

If you provisioning for a pulley maid you probably want an MVHR outlet directly above it to suck out the humidity. 

 

If that is all inn one room, I would have a think about noise from the MVHR. One of our members currently on furlough, @Jeremy Harris, also spoke well of the benefit of placing an MVHR outlet in the ceiling just outside the door from the kitchen to the hallway as a way of controlling permeation of kitchen smells.

ATB

Ferdinand

 

[tonyshouse]

I would put one duct in each of the boxings

[Russdl]

9 hours ago, tanneja said:

Then I found the Ubbink 24 duct manifolds which seemed like it would give be the option of runs to the left and right and upwards, with a mains duct connection to the MVHR unit coming from below

 

How about mounting those manifolds flat against the ceiling (inverted to the picture above) you could have the inlets on the large face/base? It would require more than your 1m2 but you could mount them side by side to allow easy future access. You would be able to use flexible attenuators straight up from the MVHR unit into the base of each manifold plus the airflow has been turned through 90° for you (bending the ducting through 90° takes up a lot of space). The downside could be that one manifold would be in the way of the other when it comes getting a ducting past manifolds.

 

Exactly how many supply and returns lines will you have?

 

 

[tanneja]

Thank you @Ferdinand @tonyshouse @Russdl

 

We have 24 ducts at the moment, split equally between fresh air and extract.  However, after comments here i think an extract for the airing cupboard would be valuable, and could balance it with a supply in a hallway, to guard the sung from kitchen and bathroom smells, so perhaps 26.

 

An attempt at placing the ductwork is here.  Obviously placement will never turn out as your hope, but felt relatively realistic:

 

 

Here the main intake from external duct runs up inside the planned void above the window.  It was there solely to house the 11 or 12 x 75mm ducts, but if I imagine for a moment that these ducts would cooperate with perfect relatively placement, it seems they could coexist with the main intake:

 

 

This would space the external vents by just over 3m, at the same height as each other.  I would need to think about access from underneath for a prefilter near where the intake punctures the external wall, no going to be as convenient as @Russdl.  It would likely mean a custom box.  Similar access issues with the filter on the exhaust leg where it would be buried behind the manifolds.

 

An orientation that just occurred is to have the distribution boxes back to back, and use 75mm elbows attached to the distribution box where necessary to set the runs on their way from just two sides of the box, i.e. the top, and the side facing the external wall.  I would have 16 ports on each manifold to use, so enough.  And would be able to get into the guts of each distribution box from the outside presumably making balancing possible.  All a bit tight, and still questionable access to the extract filter box once the 75mm ducts in in place.

 

 

Still very interested in any other workarounds  thank you all for your patience and assistance.

[Mr Punter]

When I did one of these it was a Vent Axia Sentinel Kinetic Plus and I got their approved supplier to do a design.  It worked OK.  It was not a radial system based around manifolds and used 125mm rigid duct with tees / branches.  On a small 3 storey there were only 2 main ducts vertically - for the supply and extract.

 

Make sure there is space around the unit to remove the filters for cleaning.

 

It can be better to have the extract vents within the shower areas.  The supply vents were sited away from the door into the room, so the air travels across and under the door gap, leaving no dead areas.

 

Avoid clashes with SVPs.

[Russdl]

14 hours ago, tanneja said:

after comments here i think an extract for the airing cupboard

That may not be the best idea. The airing cupboard is likely to be the warmest room in the house, probably only filled with clean clothes that are maybe slightly damp. With an extract in there you’ll be sending that warm air straight outside (via the heat exchanger) and getting slightly less warm air back. If the airing cupboard could vent to the hallway  you could spread some of that warm clean smelling air around the house before expelling it. 

[joe90]

14 hours ago, Russdl said:

That may not be the best idea. The airing cupboard is likely to be the warmest room in the house, probably only filled with clean clothes that are maybe slightly damp. With an extract in there you’ll be sending that warm air straight outside (via the heat exchanger) and getting slightly less warm air back. If the airing cupboard could vent to the hallway  you could spread some of that warm clean smelling air around the house before expelling it. 

I concur, I didn’t put an extract in the airing cupboard, it’s central to the house so any (minimal) heat that escapes warms the upstairs (in fact SWMBO says the airing cupboard is not warm enough ?).

[tanneja]

Thanks @Russdl @joe90, so give the air from the clothes drying a chance to dissipate it's heat and moisture to the wider building.  Thank you for the advice.

 

Are there any views on having a vented tumble dryer venting internally and the MVHR extracting excess moisture somehow?  My sense is that the speed of drying for a vented vs other dryer types is far quicker for a vented.  Speed is quite useful to us.

[joe90]

Vented tumble driers waste their heat to the outside, condensing driers keep the heat within the house and (most) of the moisture condenses out to a container/drain.

[Mr Punter]

With a vented dryer you are throwing energy straight out of the wall.  You could get rid of the MVHR and just leave the windows open!

 

Why the rush for quick drying?

[tanneja]

I was considering whether venting internally was viable, perhaps direct into an MVHR exhaust, thereby retaining some of the heat via the heat exchanger, dealing with the excess moisture, and achieving the dry times of the vented machines.  The rush is we tend not to iron, so wait for the load to dry, then take out and immediately fold.  If left in the tumble and allowed to cool, the clothes crease.  A shorter dry time allows you to keep your focus and remember when the dryer will be ready, and just prevents washing and drying taking all day.

[Mr Punter]

40 minutes ago, tanneja said:

I was considering whether venting internally was viable, perhaps direct into an MVHR exhaust, thereby retaining some of the heat via the heat exchanger, dealing with the excess moisture, and achieving the dry times of the vented machines.  The rush is we tend not to iron, so wait for the load to dry, then take out and immediately fold.  If left in the tumble and allowed to cool, the clothes crease.  A shorter dry time allows you to keep your focus and remember when the dryer will be ready, and just prevents washing and drying taking all day.

 

You could probably get one with a timer so it finishes when you want it to.  I don't know if they have a setting where they just tumble intermittently at the end - a bit like a concrete lorry - to stop the stuff creasing?  The heat pump ones are really efficient, but they take even longer.  The ones with larger drums crease less.

 

Putting the exhaust into the MVHR may overheat other rooms, but ask the supplier what they think.