Browse Forums Windows & Doors 1 Jul 10, 2010 11:44 am My builder has just notified me that our current plans don't pass the requirements for thermal efficiency for the upstairs areas. They have informed me that by reducing the window size or using low E glass (told me this was an expensive option) it will then pass. We would like to put in double glazing throughout the house and are still doing the sums to see if this is viable, I'm assuming that if we went for double glazing the current plans would pass? Re: Plans don't pass thermal efficiency requirements 2Jul 10, 2010 12:21 pm I expect most of your windows are on the south side... Best not to have glass on the south side, mostly on the north but Nil-minimal on the West. Where you are coming from is where you are going to... Re: Plans don't pass thermal efficiency requirements 4Jul 10, 2010 3:17 pm Does you current plan close to passing or is it missing by quite a bit? Double glazing can be expensive, especially with builder mark-up. If you can post your plans you might get some alternate ideas. Re: Plans don't pass thermal efficiency requirements 5Jul 17, 2010 10:15 am Maybe there are some ideas for your or your designer / rater in this paper. http://www.absa.net.au/files/public/New ... 0Floyd.pdf Re: Plans don't pass thermal efficiency requirements 7Jul 22, 2010 11:22 pm Eccles, I am a bit sceptical about Floyd's presentation. He suggest that an east facing orientation is superior to a north facing one in contrast to standard passive solar advice. Having lived in a house with minimal north glazing and MBR facing east, I can say that this is rubbish. Even on a sunny winter day, the only warm part of the house was the bit of corridor where a patch of sunshine shone during the middle of the day. My toddler had already worked it out by playing there with her toys. Now that we have an extensive north orientation, we can pretty much dispense with heating as long it is a sunny day. I note that ABSA gives no weight to orientation (which is a cost-neutral intervention) but places emphasis on additional components such as insulation and double glazing. It sound like just a rehash of the tired 5 star standards. Re: Plans don't pass thermal efficiency requirements 8Jul 25, 2010 10:12 pm Dymonite Floyd is the President of the Association of Building Sustainability Assessors (ABSA). They are the association that accredits and registers house raters. Clearly he should know how to use the rating tools. The paper is a bit misleading in orientation in that I think that in the paper an easterly orientation may refer to the front of the house facing east. If this is the case then the rooms in the house that contains the living areas (and bed 1) is facing north when the front of the house is facing east. But you are right – the house that they are rating does not follow what would be good passive solar design principles. There is no eaves or other shading of the windows. As you say the rating has just been achieved by upping insulation. It clearly shows that the current rating systems do not give hardly any weighting to good passive solar design or orientation. There seems to be only 0.3 to 0.4 of a starband for good orientation over a bad orientation. So even with the front of the house facing west and the long face of the house, with all of the living areas, facing south (the worst orientation for that house design) there is only minimal penalty. It certainly reinforces my doubts about the assumptions and theoretical basis that must be incorporated into the ratings programs. Re: Plans don't pass thermal efficiency requirements 9Jul 25, 2010 10:33 pm My feeling is that appropriate orientation probably contributes to at least 50% of the thermal efficiency of the building i.e. equivalent to the sum total of all other components such as weather-sealing, insulation, radiant barriers and double glazing. The magnitude of heat transfer by solar radiation is far greater than the fluxes by conduction and convection. This can either provide significant warmth during a cold but sunny winter day or result in significant overheating in a unshaded house over summer. The significance of orientation during winter cannot be underestimated. Without solar access, there is a continual net loss of heat during the 24 hour period. Re: Plans don't pass thermal efficiency requirements 10Jul 26, 2010 12:39 am Dymo once again you have done a great job in explaining the way to go! Where you are coming from is where you are going to... Re: Plans don't pass thermal efficiency requirements 11Jul 26, 2010 6:48 am dymonite69 My feeling is that appropriate orientation probably contributes to at least 50% of the thermal efficiency of the building i.e. equivalent to the sum total of all other components such as weather-sealing, insulation, radiant barriers and double glazing. The magnitude of heat transfer by solar radiation is far greater than the fluxes by conduction and convection. This can either provide significant warmth during a cold but sunny winter day or result in significant overheating in a unshaded house over summer. The significance of orientation during winter cannot be underestimated. Without solar access, there is a continual net loss of heat during the 24 hour period. Very accurate... "on average"... here I am in a rehab hospital in winter, in a room maybe 5m x 4m, the wall facing South has one single glazed window 1m high by 2.4m wide. And it's true on a sunny day, it's warm, even hot and certainly too hot in front of the window. There's an aluminium awning about 1m deep over the window to reduce solar heating in the summer. On a sunless cold day, the window sucks radiant and conducted heat from the room and from anything within 1m of the window, - the power supplies are close to the window so that's where my "desk" is , and the door is at the other end of the room. Comfort is a set of average data, never static. This window provides welcome light and views of the outside world, but it is only comfortable on average... it is either too hot or too cold. It's true, at night the roller blind makes a huge difference, and I even leave it down during the sunless cold days sometimes when I am at the laptop. In my last hospital room, a shared high dependency room, the South wall was entirely glass, 15sq.m. for a room maybe 6m x 7m. The beds adjacent to the windows were well in excess of 30 degrees in the winter. Welcome heat, if it could be circulated, very unwelcome when it is localised and you still have space heating. That window generated 30kW on a sunny day!!! Enough for a whole house and more! Solar heat gain sounds positive, the experience is not so positive. It needs to be planned to distribute the "gain" and it needs firm control. In the end, if you want natural light and views, and a practical home design, your best control is the building fabric. For the cost of forgoing one bifold door or Caesarstone benchtop, you can probably have exactly what you want in terms of orientation, views and design, and that is by using better technology in your materials. Compromises for solar heat gain are fine, but don't build your life around it, because unless you design your heat distribution system (windows and space heating and thermal mass) really well, you will still fry in the sun and freeze when it is cloudy and cold - which "on average" is fine . Remembering that a man with one leg encased in ice and the other in a bucket of boiling water is said, statistically, "on average", to be comfortable. Ed "ECOECO" At 'EcoEco', we design windows, we design the best windows, we do it for you, so that when you’re happy we are happy. Tel. 1800 326 326 Re: Plans don't pass thermal efficiency requirements 12Jul 26, 2010 10:46 am The major temptation and mistake for passive solar designers is to overglaze. the premise is that if a little sun is good perhaps a lot is better. As you pointed out you can rapidly overheat a room if there is too much glazing. The other downside is that it is also a major portal of heat loss (double glazed or otherwise) at night. The trick is to admit enough sun to keep the room warm when it is sunny - but not too much. It is important to also distribute the glazing evenly through the house so each room gets the appropriate amount of sun. You just can't turn one room into a greenhouse and keep the other rooms relatively windowless. The greenhouse will be a furnace in the day and freezing in the day whilst the rest of the house just remains cold. Another important component is to use heavy weight building materials to help store and buffer the heat energy. The thermal mass of bricks or concrete inside the house will absorb a lot of the extra heat and keep the temperatures far more stable. A lightweight building heats up very quickly and air can't hold much heat before the temperature rises uncomfortably. Re: Plans don't pass thermal efficiency requirements 13Jul 26, 2010 11:15 am dymonite69 The major temptation and mistake for passive solar designers is to overglaze. the premise is that if a little sun is good perhaps a lot is better. As you pointed out you can rapidly overheat a room if there is too much glazing. The other downside is that it is also a major portal of heat loss (double glazed or otherwise) at night. The trick is to admit enough sun to keep the room warm when it is sunny - but not too much. It is important to also distribute the glazing evenly through the house so each room gets the appropriate amount of sun. You just can't turn one room into a greenhouse and keep the other rooms relatively windowless. The greenhouse will be a furnace in the day and freezing in the day whilst the rest of the house just remains cold. Another important component is to use heavy weight building materials to help store and buffer the heat energy. The thermal mass of bricks or concrete inside the house will absorb a lot of the extra heat and keep the temperatures far more stable. A lightweight building heats up very quickly and air can't hold much heat before the temperature rises uncomfortably. You make me so ... can't even have an argument... you are right of course!!! But it needs more that myths and guesswork, it needs applied science. And to make sure you hit the mark you must build the energy efficient materials in to the equation at the start, then you will ensure you don't fall short. The rating software is all about averaging too... so it also doesn't cut it where comfort is concerned, but I am sure on a national or regional basis, "on average" it delivers real savings, just not for every individual and does nothing for comfort levels. Double glazed windows lose heat at night or on cold sunless days, that's true, but nowhere near as much as single glazed windows. And if you want to stay even warmer, you can add Low-E on surface 2 to keep the radiant heat in, which I think may also be very useful in protecting the benefits of internal thermal mass, which of course reradiates the stored energy. Ed "ECOECO" At 'EcoEco', we design windows, we design the best windows, we do it for you, so that when you’re happy we are happy. Tel. 1800 326 326 go upvc window frames ensure insulation under colorbond. not just sarking, lighter color roof also not sure if you have seen this viewtopic.php?t=5823 last couple of pages… 4 110572 This was on google. Development controls 2.3.1 Front setback D1 New buildings within residential areas shall adhere to a front building line, which is 5.5-6m to the… 1 3670 I'm wondering if anyone knows what the requirements are of a builder to be eligible to hold Domestic Building Insurance for proposed works. https://www.dbi.vmia.vic.gov.au… 0 3334 |