Browse Forums Windows & Doors Re: Low-E glass and passive solar heating 143Aug 03, 2009 9:19 pm Where you are coming from is where you are going to... Re: Low-E glass and passive solar heating 150Aug 19, 2009 8:26 pm dymonite69 The other empirical study I referenced, the 16% variance in U value occurred with fairly small changes in wind speed which suggests that the effect is still significant in 'normal' conditions. Having said this, if double glazing is susceptible to this effect then single glazing is even more so. For a 25% increase in U value: single glaze U value 6 deteriorates to 8 in fresh gale versus double glaze 4 deteriorates to 5. In other words, all forms of insulation will be relatively affected by air movement but the absolute change is lessened with good insulation. Finally, there is a warning that is issued by First Rate that instructed AC installers not to point duct outlets towards the window because of the convective heat losses that it would induce. There is still a significant argument to have curtains to prevent the window surface air film being broken by air movement. Makes plenty of sense I asked about the A/C duct vent outlets on another forum, the A/C guy's who answered said they always point them in all direction when installing them, not one said not to point the outlets towards the windows! I guess they just throw them in and say cya call me if you want to spend some more money So I wonder how the wind would affect a S/G window with curtains? Last year I added a large number of roller shutters to my windows, (we already had roman blinds fitted inside the window frame), and this made a huge difference to the heating of the home (this was before I found this forum & another), but not to much on the cooling which was the original problem. (So I learnt the hard way that the heat is due to the thermal overload coming from my roof though I still have west wall & window issues & all-round wall insulation issues still to sort out I'm currently on the look out for a blow-in product that will insulate & thermally reflect to put in my walls. Re: Low-E glass and passive solar heating 151Aug 22, 2009 11:58 am 12star - What sort of walls do you have? Dyno said Quote: The other empirical study I referenced, the 16% variance in U value occurred with fairly small changes in wind speed which suggests that the effect is still significant in 'normal' conditions. Having said this, if double glazing is susceptible to this effect then single glazing is even more so. Suppose that explains why it's colder on windy days As per the above post - I am sure it all has an effect, but IMO it's really case of how much in real terms of heat loss or temperature gains does that impact on the windows overall performance - and short of external shutters to stop the wind movement there is not a lot you can do about it. Re: Low-E glass and passive solar heating 152Aug 22, 2009 12:09 pm Yak_Chat 12star - What sort of walls do you have? Dyno said Quote: The other empirical study I referenced, the 16% variance in U value occurred with fairly small changes in wind speed which suggests that the effect is still significant in 'normal' conditions. Having said this, if double glazing is susceptible to this effect then single glazing is even more so. Suppose that explains why it's colder on windy days As per the above post - I am sure it all has an effect, but IMO it's really case of how much in real terms of heat loss or temperature gains does that impact on the windows overall performance - and short of external shutters to stop the wind movement there is not a lot you can do about it. In a built up area, it will be probably not as significant but landscaping does provide significant changes in microclimate around the garden and house. If I was out bush, I'd know where I'd be heading for if the cold wind picks up. Re: Low-E glass and passive solar heating 153Aug 22, 2009 2:21 pm Yak_Chat 12star - What sort of walls do you have? bog std brick veneer upstairs, dbl brick lower1/2, built into a hill so only have a half house on the bottom...basically a garage & a rumpus room; the rest of the house (upstairs) has all the living area (bed rms, ktn, lounge & wet areas) Have a nth facing house with majority of windows facing nth (living areas), & a couple of Lg west windows (street views) Re: Low-E glass and passive solar heating 154Aug 22, 2009 2:56 pm The best prooduct is rockwool treated with a moisture repelent - it's certified as suitable for inside brick / briock veneer walls when a vapour barrier isn't present and has been tested in a NZ facility. Not sure that a silver foil mixed in with it would make much difference as it would not be reflecting in the same direction so would degrade it's performance I'd think. And getting a flat sheet of foil in there is not possible due to the brick ties etc. dyno - Quote: If I was out bush, I'd know where I'd be heading for if the cold wind picks up. Can't be done when there is fencing to be done - it's a case of the drizabone, (wind barrier/shutters) gloves (draft protectors) and a nice hat (thermal curtains for the head) and lots of thermal gear (part of the double glazing) But it sure is nice when you have a hot bath and sit by the fire afterwards Steve 0 5065 4 6255 If you can calculate the reasonable charged head from let's say 100mm below the gutter to the top of where the vertical riser's horizontal discharge pipe will be, that… 11 17607 |