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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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    • CommentAuthorludite
    • CommentTimeAug 4th 2008
     
    I tried to respond to a comment made by fostertom on another thread and the tinternet played up. So I decided to start a new thread with my query instead.

    I suggested that perhaps opaque glass could be used on a south facing side, to make the most of passive solar gain, but prevent you overlooking neighbours houses.

    Fostertom sensibly pointed out that you can't see views through opaque glass.

    This brings me to a dilemma.

    The cottage we hope to move to is screened from the south by a low range of outbuildings. Our view to the North and West is fantastic - but it is also where the worst of the weather comes from.

    I won't be alone in this. People living in barn conversions ( Barns were built to protect the farmhouse from the worst of the weather) probably have the same problem. As will people in new builds (where the planners have stuffed as many houses as possible on to a site, regardless of their orientation).

    When I specified to the two architects we employed, that I didn't want any doors on the north side - or any large windows (because of heat loss). They looked at me as if I was a 'sad old Ludite', and gently explained that:

    Modern glazing/insulation is so much better these days, you can have doors and big windows (to make the most of the views) any where we put them - including all over the north side. . . . . .

    I don't believe them:cry::sad:

    Is it me? Who's right? The experts? or little old 'refusing to keep up with the times' me?
    • CommentAuthorludite
    • CommentTimeAug 4th 2008
     
    Sorry. I also forgot to add the 'feng shui' concept. Although I don't hold with many ideas, I have noticed that living in a place with massive floor to ceiling windows, is a little like living in an aquarium. You might enjoy the views, but all and sundry can see you too!

    I've noticed that many people with windows like these tend to put their couch in front of them. This means that you sit in the couch and face the opposite wall - not the view.
    •  
      CommentAuthorrogerwhit
    • CommentTimeAug 5th 2008
     
    Posted By: luditesit in the couch and face the opposite wall - not the view
    so that you can read the ad news in the newspaper with the light coming sensibly over your shoulder ...
    •  
      CommentAuthorfostertom
    • CommentTimeAug 5th 2008
     
    Yes, you have to really want to live in a fishbowl, for some good reason like fabulous view and no one to peer in at you.

    "screened from the south by a low range of outbuildings" - does that mean you've got privacy from the south, or that your south wall is sunless? What about sideways sun onto your S wall, i.e. from SE, SW? Even if the S wall is sunless, maybe the S roof is high enough to receive plenty of sun, and could act as your solar collector - and work out how you then make use of what's collected.

    Don't rule out view windows to N or W. The overall solar gain + heat loss package has to be designed and problem-solved so it works. Can your architect do that? As always, the solution will be very site-specific, client (you)-specific, and creative, so hard to comment without being involved.
    • CommentAuthorludite
    • CommentTimeAug 5th 2008
     
    There's no view from the south, but the upper wall and the roof will be fantastic collectors and are where we'll be siting the solar for our hot water.

    Eventually I want to add a 'room/conservatory' to the north side which will protect the cold side of the house from the worst of the weather. I hope to get it to stick out (making the house footprint a 'L' shape) so that we can have an outside patio area protected from the east - by the house, and the north , by the new room. The new room will therefore also be south facing on one side, and it's where we might eventually put pv - if it turns out to be economically viable.

    rogerwhit - of course!! I just think it looks strange seeing the back of a couch, when they could just reduce the depth of the windows and get the same effect.:smile:
    •  
      CommentAuthorfostertom
    • CommentTimeAug 5th 2008
     
    ludite, so what's the question? BTW, I don't understand the rear extension/patio orientation - sounds like yr description is 90o out somewhere. Is it in fact more like SW/NE?
    • CommentAuthorludite
    • CommentTimeAug 5th 2008
     
    Sorry fostertom. Its just that on another post I mentioned opaque winows - if you don't like the view or don't want to overlook others - if you wanted passive south solar gain.

    You then said that there were other ways of getting the solar gain and you didn't need massive south facing windows.

    I then slept on the concept - this forum gives me things I like to think about before falling asleep.

    I thought about all the houses you see in mags, and on progs like grand designs. . . . . . massive glazing, a bit pretentious at times. I thought about 'grandma' saying how all your heat goes out of the windows. I thought about the architects comments - about it being fine to have windows/doors on the north side of houses (improved insulation and glazing techniques). I got to thinking about the 'image' that we are presented with - open plan, bare foot wandering, coffee freshly ground, no dust, nice art works etc, , , , , , , and the reality - heat loss in the winter, condensation, and the placing of furniture.

    I've said it before on this forum, but my real interest is separating the 'image' of a house from the reality. It's a bit of a complex idea that is hard for me to conceptualize in the brief format of a thread.

    I've got really critical about domestic architecture recently. I haven't seen any houses anywhere that live up to what I expect my 'dream house' will be like. Time and motion experiments,. . . . 'laziness' if you like. A house needs to work for me, that includes all the stages of a life. If houses are designed properly they won't need to be altered and messed around with as much - and we will all save time resources and money.

    :bigsmile:
  1.  
    Surely there is another alternative (especially if you are a little shy :wink:) why not specify a nice coating on your windows that is reflective (to the degree you specify), then you get better heat characteristics, improved privacy AND you can still see out! Of course then people might 1/wonder what you are doing even more 2/questions your asthetic taste (think reflective car windows and US condos ugh!) and, finally, 3/think you are made of money (given how much these films are) - me, I say more window = less SAD, more feeling of space...and bu$$er the the nosey neighbours. :smile:

    BTW anyone given an opinion on whether energy conservation films (for hot and cold conditions - because I live in Italy) are cost effective?
    • CommentAuthorjoe.e
    • CommentTimeOct 13th 2008
     
    There are other ways of obscuring a view and getting privacy while still getting light in. Sandblasting is good - sandblasted glass lets in most of the light but is pleasantly obscure, with a slightly sparkly frosted effect. Artistic types can order a sheet of glass, cover it with self-adhesive vinyl and cut out a pattern with a scalpel. Depending on the balance of clear and frosted glass you want you can either leave lots of vinyl or take most of it off. Then take it to someone who does sandblasting; then take it to your DG manufacturer and have them use it as the middle sheet in your triple glazing (or in DG with the blasted side inside). I once made someone a nice set of windows with freehand vines growing all over, with tendrils, grapes and so on. Gives very good privacy by day and almost none at night.
    As for the question of windows on buildings, I would have thought that it would be an unusual interior layout that could allow no windows at all on the north side (or a very small house).
    •  
      CommentAuthorfostertom
    • CommentTimeOct 13th 2008 edited
     
    Posted By: joe.eI would have thought that it would be an unusual interior layout that could allow no windows at all on the north side
    Unusual maybe but not a problem. Needn't be 'no windows at all' - small ones e.g. bathroom, utility, study or even small bedroom OK. If you go the heavy back (north) wall/light airy front (south) you tend toward that layout. True the perimeter to area ratio goes up but not vastly and solar performance gain may outweigh surface loss. Building tight along a plot's north boundary with a basically blank wall can make the very best of a small plot, instead of splitting the plot into two titchy bits, front and back - and often 1m wide useless strips down the side as well. Not so suitable for 'housing' as opposed to individual houses on a bigger plot - but even then e.g http://www.ruralzed.com//home.php goes a long way in that direction.
    • CommentAuthorandy t
    • CommentTimeOct 20th 2008
     
    I work in glazing manufacture, and the industry is working towards soon to be implemented 'window energy ratings' (wers). The ratings are for overall window+ glass construction, as opposed to previous centre pane 'u' value of the sealed unit only. The calculation takes into account solar gain, or 'G' value, 'U' value of frame and sealed unit, and air leakage. Taking all these factors into account an 'A' rated frame has a zero heat loss minimum. Further details can be found on the British fenestration ratings council website, (google BFRC) where 'A' rated fabricators are listed. Optimum sealed unit construction for thermal performance and solar gain is 4mm S.G.G. Diamant Low iron glass/16mm cavity 90% argon filled/4mm S.G.G. Planitherm Total.
    Er, I'm new here, so maybe you guys already know this stuff...:bigsmile:
    •  
      CommentAuthorfostertom
    • CommentTimeOct 20th 2008 edited
     
    No that's great andy t, to have insiders on the forum.

    However, it's outrageous if Energy Ratings are going to assume and take credit for solar gain. Sure, that should go into building performance calculations, but it's out of order for a window design to assume solar gain. The amount of solar gain a given window gets is completely dependent on the orientation of the window, the horizon of shading elements as installed - other buildings, trees etc, and local weather data - cloud hours vs clear sky. Any attempt to assume a solar gain factor is just a marketing scam to massage the figures. I am apalled. Tell me I'm wrong.

    Any NE to NW facing window will be nett energy gainer, year-round - but that's no comfort when the summer gain is just an overheating problem and can't be stored for when it's needed, in winter. At very least, any account taken of solar gain should be limited to the useful gain as experienced within the heating season. The suggestion that windows might be rated 'zero heat loss' says it all - only in very special cases, within the heating season - and those cases more to do with the rest of the building's ability to store heat, than to the window.
    • CommentAuthortony
    • CommentTimeOct 20th 2008
     
    I agree with Tom it simply is not possible to allow solar gain into window U values -- reasons as Tom states
    • CommentAuthorandy t
    • CommentTimeOct 20th 2008
     
    Thoroughly agree with your comments about solar gain. I think the energy ratings should be founded on the ability of the window to retain heat. As you say the solar gain factor is too much of a variable.
    I think the reason it is included is a marketing strategy from Pilkington, as 'K' glass is not as thermally efficient as Saint Gobain Planitherm Total at retaining heat, whereas 'K' has a higher solar gain factor. Their respective version of performance can be checked on the links below.
    http://solaglas.sggs.com/SolaGlas/News/SGG_EcoClear/EcoClear_CB-A.asp
    http://www.pilkington.com/resources/newsletterloweglass.pdf

    I think the biggest failing of the window energy rating system is the fact that the test window is an oversize product, that is outside the range of both profile extruder and hardware manufacturer, size recommendations. It will never be manufactured or installed!
    •  
      CommentAuthorfostertom
    • CommentTimeOct 20th 2008
     
    It gets worse! Anyway, I though the window energy rating system came in a couple of years ago - but it only really serves the retail replacement dg market.
    • CommentAuthorandy t
    • CommentTimeOct 20th 2008
     
    The rating system was created in an advisory capacity a couple of years ago and is being seen now on some plans, usually specifying a minimum C rated frame.
    The doc L requirements are expected to be mandatory in early 2010 for a minimum C rated frame (new build) with an A rated frame required in 2016 (new build).
    These are proposed requirements for every installer as far as I understand. Be they double glazing co, building company, self builder, or cave dweller. The way I've interpreted the bumf anyway. (been wrong once or twice before!)
    One more scary fact: energy saving difference between an A rated frame and a C rated frame on an average house with 15m2 of windows is approx £40.00 per annum according to extrusion company Profile 22. (One quiet Saturday night out with a curry after, for me and her) Although they also say that over 35 years the difference will save 30 tonnes of co2 emmisions, which is positive.
    I would dearly like to know how these companies come up with these statistics tho...
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