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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

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  1.  
    Posted By: bxmanThat sounds very reasonable Paul mostly Hydro and Nuclear I imagine .


    99.8% Hydro - the one nuclear plant is being decommissioned and there is now some wind, but not much. That 15000kWh figure is a bit misleading, though, as we use a water-to-air GSHP so total delivered heat is more like 36000kWh - which still isn't bad for a 180m2 house with solid walls and no more than 1/2-1" of insulation. It's all about air leakage! We're not tight enough to require an HRV though. Over here in winter, there's definitely no need to put the shower extractor fan on. Since we reduced the air leakage, though, the house doesn't feel as dry as it used to. Only a tiny bit of condensation on the windows, though, when it's below -18C, and only at the bottom edges.

    Paul in Montreal.
    • CommentAuthoratomicbisf
    • CommentTimeDec 22nd 2013
     
    Surely if it's sufficiently cold outside, it doesn't matter about the relative humidity as cold air can contain little water vapour? Eyeballing a graph, 0C 100% RH air warmed to 20C will reduce its relative humidity to about 25%.
  2.  
    Posted By: atomicbisfEyeballing a graph, 0C 100% RH air warmed to 20C will reduce its relative humidity to about 25%.


    Indeed. As I said, -26C 61% RH air warmed to 21C is about 1% RH (ouch!)

    Paul in Montreal.
    •  
      CommentAuthorSteamyTea
    • CommentTimeDec 23rd 2013
     
    Paul
    Is everything covered in a nice fluffy blanket of snow at the moment?
  3.  
    Well ladies and Gents there is a turn up for the books, Fantronics seem to be a no frills low margin company; accordingly, I didn't hope or even ask for anything from them. However, they are about to start selling the 100 VUT version and would I like one of their first samples to try for free?!!!

    In all fairness I should mention that they have pointed out that they sell overseas (albeit not from their Fantronix outlet) where this unit might be appropriate and that it would be appropriate in the UK too for hydroponics situations, a point none of us spotted. The Vents 100-P Mini VUT version will be only very slightly more expensive making it a no-brainer for almost any small 70-100m2 house/apartment - there really is nothing out there sized at this level and the next nearest void mounted unit is £900. It has a SFP of under 2, so not great but not dire either - what do you expect for circa £300!
  4.  
    Posted By: SteamyTeaIs everything covered in a nice fluffy blanket of snow at the moment?


    We had 40cm of snow the weekend of Dec 14, which was a bit unusual as the temperature stayed around -15C the whole time. This past weekend, another 20cm of mixed precipitation with snow, ice pellets and freezing rain, though we escaped the bulk of that, which fell mainly over Ontario where they had about 30-40mm of it. Going to be a cold and sunny christmas with daytime highs around -14C :)

    The photo was taken on Dec 15th - there was no snow there 2 days before.

    Paul in Montreal.
    • CommentAuthorbxman
    • CommentTimeDec 23rd 2013
     
    glad to hear you are Ok we had reports of 1000's of you in Toronto being with out power first thing this morning.
    •  
      CommentAuthorSteamyTea
    • CommentTimeDec 23rd 2013 edited
     
  5.  
    Posted By: bxmanglad to hear you are Ok we had reports of 1000's of you in Toronto being with out power first thing this morning.


    That's correct - but fortunately Toronto is 550km west of Montreal. We did have a bad icestorm in early January 1998 - which, up until this year's floods in Alberta, was the most expensive natural disaster in Canadian history. We had between 100 and 150mm ice accumulation - about 3x as much as the current storm in Toronto and there were millions of people without power. Some of the worst affect areas were without power for over a month. Imagine 4 days of heavy rain (and thunderstorms) with a temperature around -8C.

    Paul in Montreal.
    • CommentAuthorEd Davies
    • CommentTimeDec 25th 2013
     
    Gotanewlife, thanks for pointing to those units. Plan A for me is a home-brew MHRV but if that seems to be a problem with SAP and building regs one of them might well be a good option.
  6.  
    Posted By: GotanewlifeWell ladies and Gents there is a turn up for the books, Fantronics seem to be a no frills low margin company; accordingly, I didn't hope or even ask for anything from them. However, they are about to start selling the 100 VUT version and would I like one of their first samples to try for free?!!!

    In all fairness I should mention that they have pointed out that they sell overseas (albeit not from their Fantronix outlet) where this unit might be appropriate and that it would be appropriate in the UK too for hydroponics situations, a point none of us spotted. The Vents 100-P Mini VUT version will be only very slightly more expensive making it a no-brainer for almost any small 70-100m2 house/apartment - there really is nothing out there sized at this level and the next nearest void mounted unit is £900. It has a SFP of under 2, so not great but not dire either - what do you expect for circa £300!


    Well at last I've got the 100 VUT version instead of the VUE, ie the one with the condensate drain.

    But how did you connect the condensate drain? I was expecting something that would connect to one of the standard waste pipe sizes such as the 21.5 mm solvent weld I have for the boiler. Instead it has a little metal outlet with a diameter of about 12 mm that looks as though its designed to have flexible plastic tube pushed onto it. The manual doesn't give any clues on the diameter or what type of pipe it takes.

    Ed
    •  
      CommentAuthordjh
    • CommentTimeDec 4th 2015
     
    Posted By: atomicbisfBut how did you connect the condensate drain? I was expecting something that would connect to one of the standard waste pipe sizes such as the 21.5 mm solvent weld I have for the boiler. Instead it has a little metal outlet with a diameter of about 12 mm that looks as though its designed to have flexible plastic tube pushed onto it. The manual doesn't give any clues on the diameter or what type of pipe it takes.

    Have you asked them?

    My Brink came with an odd size but they supplied an adaptor. But they expect you to dip the pipe into a deep trap, kind of like a short washing machine standpipe. So the pipe doesn't have to match any other plumbing because there's an air gap between it and the wall of the trap. We didn't want a wet trap though, because the water is bound to evaporate so we connected it to a HepVO trap. So we were grateful for the adapter.
  7.  
    Posted By: djh
    Posted By: atomicbisfBut how did you connect the condensate drain? I was expecting something that would connect to one of the standard waste pipe sizes such as the 21.5 mm solvent weld I have for the boiler. Instead it has a little metal outlet with a diameter of about 12 mm that looks as though its designed to have flexible plastic tube pushed onto it. The manual doesn't give any clues on the diameter or what type of pipe it takes.

    Have you asked them?

    My Brink came with an odd size but they supplied an adaptor. But they expect you to dip the pipe into a deep trap, kind of like a short washing machine standpipe. So the pipe doesn't have to match any other plumbing because there's an air gap between it and the wall of the trap. We didn't want a wet trap though, because the water is bound to evaporate so we connected it to a HepVO trap. So we were grateful for the adapter.


    Not yet, as I've pestered them enough as it is! A flexible hose that I had left over from an aquarium filter fits, was thinking of just dipping that into the trap but was concerned that the air break would cause the water in the trap to evaporate. HepVo might be a good idea for this reason.

    Ed
    • CommentAuthorGotanewlife
    • CommentTimeDec 4th 2015 edited
     
    I think mine has a screw thread but I'll check and let you know in the am.
    Posted By: atomicbisfWell at last I've got the 100 VUT version instead of the VUE,
    C'mom spill all - what happened, how much etc. Their site now says it o0nly sells the VUT but that it recuperates the moisture so IF and I mean IF they really are selling the VUT then they have not changed the specification on their website!!!

    No don't go HepO, bad idea - just plumb the pipe/tube in with a U bend
  8.  
    Posted By: GotanewlifeI think mine has a screw thread but I'll check and let you know in the am.
    Posted By: atomicbisfWell at last I've got the 100 VUT version instead of the VUE,
    C'mom spill all - what happened, how much etc. Their site now says it o0nly sells the VUT but that it recuperates the moisture so IF and I mean IF they really are selling the VUT then they have not changed the specification on their website!!!

    No don't go HepO, bad idea - just plumb the pipe/tube in with a U bend


    Well it's the one listed on the Fantronix website for £199, it is not the same as the one in the downloadable manual though so it is all rather confusing. The condensate drainage is horizontal rather than vertical as illustrated in that manual.

    What do you mean by plumbing it in with a U bend? I can't think of a way to actually connect the ~ 12mm flexible tube/hose it appears to need to the 21.5 mm solvent weld condensate from the boiler (apart from just poking the former into the latter and leaving an air gap).
  9.  
    These are the specifications from the printed manual that came with it, which is different from the downloadable one, and matches the actual unit.
      VUT specs.jpg
  10.  
    And the page on the drainage:
      VUT drainage.jpg
    • CommentAuthorCerisy
    • CommentTimeDec 5th 2015
     
    We used one of the water-less traps - probably the HepVO trap - to avoid the drying out issues. No issues with smells so far.
    •  
      CommentAuthordjh
    • CommentTimeDec 6th 2015
     
    Posted By: GotanewlifeNo don't go HepO, bad idea

    What's the problem?
  11.  
    Posted By: CerisyWe used one of the water-less traps - probably the HepVO trap - to avoid the drying out issues. No issues with smells so far.
    Likewise, ours has been in use for over 2 years now without any problems.

    Although if you have a decent head height available I don't see a problem in forming a large U bend in the flexible tube that you are using, perhaps with cable clips to the wall to keep the form.
  12.  
    The condensate is in the air stream which is being blown out of the house?

    Why does it matter that there is a trap to seal this air?
  13.  
    Posted By: WillInAberdeenThe condensate is in the air stream which is being blown out of the house?

    Why does it matter that there is a trap to seal this air?


    Hi I think you're thinking of the condensateless model the thread started with, but this one definitely has a collection 'pan' in the bottom of the unit for water and a little outlet pipe. If you didn't have a trap to seal it, sewer smells would get into the unit and probably into the supply air.

    Its all very confusing but I *think* this is what happened: there were originally two units, one with an aluminium heat exchanger and condensate drainage designed for 'conventional' MVHR and one with a paper heat exchanger without condensate drainage designed for hydroponics or very cold winter climates.

    Then for some reason instead of selling the former in.the UK they instead modified the design ofvthe latter, adding a plastic heat exchanger and condensate drainage. Fantronix in in their emails speak of modifying the design for the UK rather than supplying the original aluminium exchanger unit.

    So talking about the VUT or VUE which appears to refer to the original units doesn't seem to make much sense... Confused now?!
    •  
      CommentAuthordjh
    • CommentTimeDec 6th 2015
     
    Posted By: WillInAberdeenThe condensate is in the air stream which is being blown out of the house?

    No this is condensate collected in the MVHR unit. I suppose it drains out of the heat exchanger? Or maybe it collects on the outside of the heat exchanger? I don't know. There isn't very much of it.
    • CommentAuthorGotanewlife
    • CommentTimeDec 6th 2015 edited
     
    Posted By: atomicbisfIts all very confusing but I *think* this is what happened: there were originally two units, one with an aluminium heat exchanger and condensate drainage designed for 'conventional' MVHR and one with a paper heat exchanger without condensate drainage designed for hydroponics or very cold winter climates.
    You are spot on. They were intending to sell the condensate one in the UK at a fair chunk more than the non-condensing (aka stupid) one. I have the 'proper' original VUT kindly sent to me for free after they mis-sold the VUE (I also have the VUE still as I don't want to sell on as would be irresponsible). Metal heat exchanger and a centrally located drain with a nice brass threaded attachment with good gasket etc. They obviously decided to down-spec in order to hit a lower price point. The only difference between the 2 is the heat exchanger and the condensate drain, literally everything else is identical.

    Ref the bit about U bends, air gaps etc - IMO all over-egged. The water in the U bend is exposed to air either side of the water - after a long hot summer in Italy there was still ample water in my trap, remember that you have to change/clean the filters (every 4 months, say) so you can easily add a syringe full of water if you want but also remember that, esp in UK, the thing will be condensing a fair bit; it might only be a tablespoon a day but there is no way in my experience that it will all evaporate away when in use.

    Ref the HepO - it works but it can also fail, there has been plenty of comments to this effect on here. It is used exclusively (I thought) instead of a U bend when there isn't space for a U bend or one wants to avoid one for aesthetic reasons. They are not as good as a U bend only because they won't last as long.

    The VUE is a good bit of kit, less than 1/3rd the price of a ceiling void mounted MVHR of this capacity or bigger. There is one other one out there (or was) of substantially smaller umpf and either that one or the VUE are the answer to FT's question on the 40m2 new ventilation regs question/thread.

    Other points, I didn't like the look of the seal for the 'lid' so I fitted some 3mm compressible air sealant strip around the perimeter. I din't like the look of the 'fall' to the condensate drain, so I put a chunky line of silicone around the area where the condensate was likely to fall and put a piece of food cellophane over the bit where it might touch, closed the 'lid' (ie the underside) opened played a bit, closed, let dry, removed plastic etc. All good.
    • CommentAuthoratomicbisf
    • CommentTimeDec 19th 2015
     
    Thanks Gotanewlife, I got it up and running yesterday evening though the system is not yet complete. I've got it running with one extract and one supply, the exhaust expelled through a soil vent pipe in the roof that I'd made redundant and the intake from the loft as I haven't got a suitable hole to the outside yet.

    First thing I noticed is though it makes a fair bit of noise when running, from inside the house it is quieter than I was expecting. On the low setting it's virtually silent.

    It doesn't prevent condensation in the bathroom when showering as much as I'd hoped, or clear it as quickly, but maybe my expectations were unrealistic.

    I had it on high while showering at about 2100 and then switched it to low before going to bed around midnight. By the morning there was no sign of condensation either on the bathroom or bedroom windows.
  14.  
    Well done atomicbisf!

    Re noise - mine's in a utility room and mounted on home made rubber bushes (I'll tell you how if you want) with the pipes connected via a flexible joint - on med is silent in rooms, and on high is silent in rooms according to my in-laws! Remember with more vents you will have less airflow and hence less noise. Outside (and I have 2 different MVHRs); it is amazing how noisy they are. I also fitted an attenuator 204x60 type on clean air in branch to the 2 bedrooms before it split and suspended all pipes on fabric straps or foamed in hard to existing ceiling.

    Ref clearing condensation - it is still all about the dew point - ie temp of your internal walls, temp of air in bathroom and hall/bedroom wherever it is being drawn through from and of course the RH of that internal air - then of course what is the resulting RH of the external air after it has been warmed through the MVHR - not always fantastically lower and can in some circumstances be higher for short periods. This is a basic unit - no boost timer - not even sure it is possible to retrofit - so turning up to Max and then remembering to turn down again is never really going to work. Even on max, what is it: 2ACH; so expecting a few minutes and then no condensation is usually going to be optimistic.

    Just chill - it will prevent mould and improve no end condensation and overall AQ. Just get it finished now.....
  15.  
    Gotanewlife - If you still have the original VUE unit why not order a replacement heat exchanger (HEX) as fitted to the VUT unit, swap out the HEX in the VUE unit and flog it on?
    Assuming the replacement HEX is cheaper than a complete vents 100 unit - depends how they price the spares
    • CommentAuthoratomicbisf
    • CommentTimeDec 19th 2015 edited
     
    Posted By: GotanewlifeWell done atomicbisf!

    Re noise - mine's in a utility room and mounted on home made rubber bushes (I'll tell you how if you want) with the pipes connected via a flexible joint - on med is silent in rooms, and on high is silent in rooms according to my in-laws! Remember with more vents you will have less airflow and hence less noise. Outside (and I have 2 different MVHRs); it is amazing how noisy they are. I also fitted an attenuator 204x60 type on clean air in branch to the 2 bedrooms before it split and suspended all pipes on fabric straps or foamed in hard to existing ceiling.

    Ref clearing condensation - it is still all about the dew point - ie temp of your internal walls, temp of air in bathroom and hall/bedroom wherever it is being drawn through from and of course the RH of that internal air - then of course what is the resulting RH of the external air after it has been warmed through the MVHR - not always fantastically lower and can in some circumstances be higher for short periods. This is a basic unit - no boost timer - not even sure it is possible to retrofit - so turning up to Max and then remembering to turn down again is never really going to work. Even on max, what is it: 2ACH; so expecting a few minutes and then no condensation is usually going to be optimistic.

    Just chill - it will prevent mould and improve no end condensation and overall AQ. Just get it finished now.....


    Thanks!

    I'm glad I didn't go to a huge amount of effort/expense on the noise reduction, as it seems pretty satisfactory as it is, but if it starts disturbing us I can add more.

    As the roof structure isn't really suitable for suspending the unit I've built a simple wooden framework for it that just sits on the floor of the loft and it hangs from that using threaded rods. So the framework sits on the chipboard floor of the loft which has 60mm of Knauf spaceboard underneath.

    I've used the acoustic ducting from Fantronix (http://www.fantronix.com/acatalog/Acoustic_Ducting.html) and 125mm ABS air valve grille (http://www.fantronix.com/acatalog/Air_Valve.html). The ducting is tied to the purlins in the loft, so it isn't in the way. I can't hear any air rushing type noise at either the supply or extract grille so I think they are large enough. The small amount of noise that does come though seems to come directly through the ceiling from the unit rather than through the ducting or vibration transmitted through the structure. It is less noticeable than the noise from the boiler fan next to it.

    The exhaust isn't ideal as the internal diameter of the pipe it's exhausting through is less than 100 mm, but fitting and flashing a new one would be quite a palaver so that will probably have to wait for reroofing. (Basically I've used the cut off remains of what used to be a soil vent pipe that has been removed from the loft down, where it goes through the roof it has some special flashing).

    Here it is with only the one duct fitted so far:-

    Ed
      DSC_0008_2[1].jpg
    • CommentAuthoratomicbisf
    • CommentTimeDec 19th 2015
     
    Posted By: Peter_in_HungaryGotanewlife - If you still have the original VUE unit why not order a replacement heat exchanger (HEX) as fitted to the VUT unit, swap out the HEX in the VUE unit and flog it on?
    Assuming the replacement HEX is cheaper than a complete vents 100 unit - depends how they price the spares


    I don't think that's possible unfortunately because the original design made no provision for condensate drainage. So just fitting a new HEX would leave the water with nowhere to go. The redesigned unit collects the water in the bottom 'lid' of the unit, from where it drains out through a small opening.


    Ed
    •  
      CommentAuthordjh
    • CommentTimeDec 20th 2015
     
    Posted By: atomicbisfAs the roof structure isn't really suitable for suspending the unit I've built a simple wooden framework for it that just sits on the floor of the loft and it hangs from that using threaded rods.

    The small amount of noise that does come though seems to come directly through the ceiling from the unit

    This will sound like first-order bodgery, but it is sometimes used in laboratories to acoustically isolate microscopes ...

    Just replace the threaded rods with lengths of bungee cord. It should make a massive difference. I suppose even acoustic mounts at the ends of the threaded rods would help, but bungee cord is quick, cheap and easy!
   
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