tanneja

Just to confirm, is that breakdown looking like £35k?

Can I ask this again to the forum, as I am undecided as to what would be the best arrangement for either a single 3-way or single 4-way multi split to service the whole house. My current thoughts are to have a 4-way, with 3 units downstairs, one upstairs. The one upstairs would probably be best placed above the shower room door as you emerge at the top of the stair well. Presumably the indoor unit can oscillate the air left to right to find it's way into the 4 bedrooms from there? Then downstairs, similar to where I marked previously, probably one in the snug at the front (south facing) room, one in the main living area near the kitchen, and for the third, rather than being in the gym / playroom / garage, maybe have in the porch / reception hallway, again hoping it can oscillate the air between the garage and open plan living area. Would anyone think this is a sensible arrangement? What would you do differently? Would you provision for a second unit to better cover the home volume (200m2 / 500m3)? I liked the idea of just one external unit which can provide heating (heat pump), so that I don't need planning permission. We are doing everything else we feel we can to manage solar gain, I like the idea of being able to live in a fridge if we really wanted to. Don't currently have PV, if energy usage skyrockets with bringing these in, would obviously have to look at that.

Likewise we will have to go through a tiled roof, sounds like flue units will be necessary. I have the added emphasis of wanting to be wasp proof as they interrogate every inch of the exterior of our house. We have found upwards of 10 nests everywhere as we have been renovating. Would we be hampering the intake of the MVHR is it has an integrated mesh? I certainly won't be able to be up cleaning anything. So we just go mesh-less and trust wildlife will leave us alone?

Thank you @Stones, I sincerely appreciate your assistance. I will likely be getting the Kinetic Plus B which I think you have had at one time or another. Your post on servicing yours has been pinned to my favs and will be very helpful I am sure when the time comes. I haven't managed to find posts where you describe any maintenance schedule for the ducts them selves, would you mind saying if you attempt to clean these somehow (either the external connecting or just the internal servicing sets). Again I offer my thanks

@Stones and others, if you don't mind clarifying for me, I had intended have a Vent Axia unit in my cold loft, and have the room duct runs snake around the cold loft, then going down to 1st floor and ground floor rooms. What type of insulation should I provision for that 75mm duct work? If a generous layer of Rockwool, would you then have to board over the top to avoid crushing one accidentally when going up to service the filters? p.s. I have see the attached images of the installation advice from one company and hopeful my builder would think covering the 'room to MVHR' sets of ducts in this way, without any gaps (in the pictures akin to laying a blanked over protruding duck work), would be doable. Frankly, it has to be doable, given the design decisions I have made already: I assume the foil backed glass fibre insulation that comes with the BCP kits was used for the main extract / intake pipes? I have seen references made to encasing the MVHR unit in PIR sheets, still allowing for condensate drain to function, and ability to get to the filters. Would encasing in PIR like this be advisable? Presumably summer overheating is a potential issue.

@NSS can you send me the contact via PM as i may already be in contact with them via the quote process. Thanks very much! @Russdl that is intersting, i couldn't easily find an external model on the link, if you have any pictures i would be interested as perhaps we can integrate these into the planned EWI As @Mr Punter says, i feel less concerned about losing out on winter solar gain, with heat rising I expect that bedrooms should rarely require much heating. Just to say this is a retrofit project of a 1930s semi where we are having new poured floor, new roof, EWI and triple glazing, so while will be well insulated, not a passive house by any stretch of the imagination. I expect to have to pay for heating in the future, keeping our combi boiler for now as only a couple of years old, from before we considered this project.

For what it is worth, I have tried with a few internorm suppliers to get quotes for Sage Glass, without success. And Sage Glass say the fabricator must go to them for their product, so seems too many barriers to get access to pricing let alone a finished product. Plan is to have solar glass upstairs in the east and south elevations (no west facing windows), while leaving the downstairs as regular windows, will plan plants and tress to partially shade the downstairs. I don't know who to pay to see if we will have an overheating problem, so seems like the best solution rather than aftermarket films. Will also provision for some through wall A/C in (hopefully) strategic places should we need to install for active cooling.

@MikeGrahamT21 what colour are the normal metal ones? Did you upgrade to the premium kit?

Hi all, I have measured my floor area to be 200m2 (140 downstairs, 60 upstairs). The volume is around 500m3. Which model of Vent Axia will give us the best performance (low sound, high efficiency)? We will have some relatively long double runs (15 Metres). Given all I have read on here regarding #ach, it would feel like the Advance S has sufficient capacity, but can't help question whether the Kinetic Plus B would mean better performance. https://www.bpcventilation.com/heat-recovery/heat-recovery-units?cat=29 The Sentinel has the added benefit of being able to add a wifi module, if that will be at all useful (we think we will have a budget level smart home with a degree of automation). Plan to go for the premium additional kit, but likely the designer airy valves so we can colour them to match with the ceilings. Are we paying a lumpy premium to get everything via BPC rather than components from all over the place? My builder threw away the kit I bought for a hidden toilet in favour of better bits he could get himself, so wary of the quality I might be getting. Will read more into the provisioning to clean the ducts and unit (not just the filters), as that is presumably not simple, but is essential. Please be advised the unit will be in the loft, so accessible but with a bit of effort. I offer my thinks in advance for any assistance. Regards James

Its an attractive solution until running up against the install cost being mutliples of the purchase price

We are favouring a porcelain worktop (Sapienstone), due to go see some samples early next week. Very thin relative to other worktop types, so would need bracing if to use with an overhang like a breakfast bar, but we think a secondary timber structure to support it in the reveal could look good.

I can imagine I get quoted £12k for EWI if consistent with the quotes we have had already. Do you fine people infer that I could get up to £5k of that paid as a voucher? Also, I'm not sure how the second tier works. If I am capped out in the first tier, can I get anything towards second tier? Was thinking it could cover a honeywell evohome thermostat with TRVs.

@Ferdinand why do you say EWI won't be helped? I was holding out some faint hope that this would part pay for my renovation EWI.

Thanks all for the feedback. My other half is against shutters, and I don't think external shutters or fabric would fly in the neighbourhood, we are seen as radical but opting for a grey roof tile. We also seek super low maintenance, external shutters probably have a fair bit of that to keep them in good condition? It is possible I don't have a future solar gain overheating issue. If it is very similar costs to apply an aftermarket film later vs. the option of adding solar glass now (around £10/m2) and has good durability to the elements (+10/20yrs without deterioration), then waiting and seeing is obviously the way forward. I have the impression films were more expensive than that.

Sorry for being dense, but are there any free online tools I can use to model this, or rather is this something you pay some for / purchase a tool? My current thoughts are to have the upstairs east and south elevations in the SKN176 to protect them from un-shaded sun, while leaving downstairs as normal triple glazing, as they are the windows you look out of during daylight hours, and have some tree shading for part of the day / time of year. If an analysis would be fairly realistic with determining whether we would have a summer gain issue, it feels like something worth purchasing, and put this external shading / window tinting to bed.

For what it is worth, the best solution feels like the wood frame approach, probably 50mm deep (planned 100mm deep EPS), with then having the EPS overlap the sides and top of the frame by 20mm (you can ask for the Internorm window to have XL sides and top which are 20mm wider frames than the bottom, meaning when you then bury that 20mm of those sections, the exposed frame amount looks the same both sides, top and bottom). If the windows can be fit to the front of the wood frame in this way, I see that gets the perimeter U value down to about 0.77 which is close to the internorm window itself. Speaking with various internorm sellers, seems they can fix the windows either by direct fixing screws through the frame, and / or using anchor straps that can be attached to the inside window reveal using screws and packers as per the Velfac video I linked, I would probably request both to ensure a robust attachment. Only small concern is that the internal frame fixing position for the Internorm is around the middle of the frame, so about 50mm from the front of the frame, and so could line up with the intersection of the wood frame with the masonry, which presumably isn't an ideal fixing position for the through frame mounting screws. I guess for now I would make the 50mm boxes and the fitters can micro adjust the depth of the window relative to the front of the box, based on what they are presented with. For anyone with experience, I would use marine or structural ply for the boxes? Layer up 2 thickness of 25mm I assume to get to 50mm depth? Would we use metal fixing screws to attach to the masonary?

Also interested in this and if it could help towards EWI for our renovation. Presumably it is income dependant in some way.

@NSS I'm obviously very slow, so can you clarify, in the winter months, do you cut the power to the sage glass so that you get favourable solar gain on days with sunshine? Or is this not necessary?

@Mr Punter ok, so if one were ordering tilt and turn (inward opening), would standard install be to render partially over the outer aluminium frame? The internorm we have been considering is the KF520 which is sash-less externally, the glazing is the sash. While you could overlap the external frame with render, I was curious whether this is the done thing, perhaps this velfac install was the preferred method regardless of opening system. My apologies for being so green with this.

You are right of course @Russell griffithsit is a thin coat. Looking at the velfac install thought I dont think the ewi would want to go over the frame and impact the window aesthetics. If the metal fixing elements are the same as used by velfac, where they protrude back into the house to be attached to the masonary, then as long as there is a structual cill capable of holding some of the weight of the window (like a structured foam maybe CF200 that comes up on forums), it feels quite simple to have the window sit partially in the EWI layer and the attachments all will marry up with masonary. It seems like the best practice would be do EWI first, window install second. Complication is us living on site during this. What would you advise?

Thanks very much @Ferdinand, if condensation isnt an issue, that is great to know. I'm looking back at a CF200 external cill option to have the window set 40-50mm proud, going to call internorm fitters tomorrow to ask what their install method would be (velfac have metal window mounts that attach on each edge of the window). This is the online Velfac install video, they say render finish of the reveals should be complete before install, where my builder and ewi installer said the opposite. Watching the Velfac videos, once installed you see all the frame, no render over the top or sides as was suggested to me was the way all windows go in. If Velfac videos are the standard procedure, would that mean having EWI done prior to window installer survey / measurements? What is the praticality of that happening while we are living in the orginial (not extended but having EWI and windows), will we need to have plywood window coverings in the phase between the EWI and window installs?

My sincere thanks all. We are still asking some other companies too, but struggling to get prices back, or beat out Internorm quote. It seems that a 50mm wood frame approach would bring the U value around the window opening to 1.0, where if we made a frame with 50mm of compacfoam (cf200, not done any calcs to confirm it is capable of supporting half of the near 100mm deep windows) then the U value goes down to 0.6. Not sure what low conductivity fixings you can use to attach a compacfoam frame to the masonary. I see the cost of the compac foam to be about £1200. Alternatively we have the EPS overlap the 110mm frame by 20mm, then have 20mm render (so 40mm in total) which brings the outer perimeter to around 0.84, with the window entirely held in the masonary. I understand these are likely very minimal gains thermally due to the small surface area involved, my main reason for still investigating this is one comment saying i could be inviting window consensation unless bringing up the U value where the window juntions with the wall. Is condensation a real concern if the U value is 1.8 for the line around the window perimeter? Would the 20mm EPS over the frame be the most pratical?

Yes @NSS, you are so right. External shutters seem difficult to come by and if not electric (which likely has it's own problems), a forever time investment of operating them. To be clear, you would go sage glass every day of the week, and weekends? Seems to work amazingly for you.

@MikeGrahamT21 This is likely the only option builders, EWI installers and window installers will tolerate, so seems like the compromise I will settle on. I offer my sincere thanks for your opinion.

Hi all, I have been able to get a quote for Internorm 3G with normal glazing, and with a solar grade glass called SKN 176 II (https://glassolutions.co.uk/en-gb/products/cool-lite-skn-176ii). I have not elected to get this on the large sliders as they are North facing, so to apply to fixed and T+T windows on the East and South elevations (approx. 17m2) costs an extra £1,500. My instinct is that this is a worthwhile cost for a forever coating that should do well to ensure we have minimal solar gain but hopefully not to the detriment of the view (I have one persons personal experience who attests to it being minimal impact to perceived light, but dramatic solar gain improvement). Presumably by comparison aftermarket films will have a reduced life expectancy? Part of me wants to get regular glass and see if solar gain is really an issue before committing to handing over the extra cost, and giving away some of the intensity of light but by then film is my only option. On a somewhat similar note, when ordering for company's like Internorm or others, for bathrooms, do people tend to spec for frosted glass, or apply this as an internal film themselves, or do people just use blinds and / or shutters these days? Many thanks for any guidance