Heat loss through window problems

Ross · Aug 06, 2010 1:21 pm

Hi all, am at the design stage of what am hoping will be my 2 storey eco sustainable home with NO AC and minimal heating!
North facing street-Its a modified T shape,(longish top and smaller tail) The shortish tail consists of the kitchen meals on bottom level and main bedroom above. For Kitchen/bedroom above- Large North facing glazing(doors to bottom) and a large sliding glass door on bottom facing south(for views to longish block/garden). Done all my sun angles and believe will get great sunlight in the kitchen during winter and minimal in summer, polished concrete floors throughout entrance hallway/kitchen/meals. RBV for majority of house. What I wish to know is how to stop the heat getting back out of the house at night and cold days!! I hate the idea of pelmetted curtains etc. Do wooden venetion/slats do the same thing?
At this stage there will be double glazing, defintely to the south and wondering about the north as I read that they also stop sun getting in(I suppose I could always open the door on a nice winters day?!)
There are also very large glazed windows to the North front of house both upstairs and downstairs(both bedrooms) Although this is for aesthetic reasons am wondering what to do about privacy? Have had the house designed professionally and although she has given me exzactly what I asked for I believe her knowledge of sustainable building leaves abit to be desired, but having spent $7000! what to do next?!

So anyway main question is what options are there to prevent heat escape from alot of north facing glazing and a little to the south??

kid81 · Aug 06, 2010 4:28 pm

These days most of the heat transfer is through the frame as double glazed windows should be sufficient to prevent too much transfer. Your best bet is PVC or thermally broken aluminium frames. Eco Classic is a good place to start looking into PVC and Creative Windows are currently supplying thermal break windows. the big companies such as A&L Windows and Dowell windows are not too far away (6 months maybe) from having thermal break product though

ECOECO · Aug 06, 2010 4:50 pm

kid81

These days most of the heat transfer is through the frame as double glazed windows should be sufficient to prevent too much transfer. Your best bet is PVC or thermally broken aluminium frames. Eco Classic is a good place to start looking into PVC and Creative Windows are currently supplying thermal break windows. the big companies such as A&L Windows and Dowell windows are not too far away (6 months maybe) from having thermal break product though

Thanks kid81, we supply PVC, aluminium and thermally broken aluminium.

Ed

Eccles · Aug 06, 2010 9:55 pm

Double glazing will cut down on direct solar gains compared to single glazing - perhaps up to 10%. However it will cut down conduction / convection heat losses by 33 to 50%. Therefore a net gain in winter and even better in summer to prevent heat gain.

Heavy curtains with pelmets are a good additional heat flow retarder. Don't like pelmets - if you only have 2.4 metre ceilings could consider floor to ceiling curtains - the pelmet then is not so prominent incorporated into the cornice line. Otherwise I have heard suggestions of cellular blinds being good or else lined roman blinds where the top of the blind is flush against the wall and also the sides of the blind when down. (Care needs to be taken not to block winter solar heat gains with the blinds.)

Must keep sun off glass in summer - eaves or other shading structure to North.

References:
Sustainability Vic
http://www.sustainability.vic.gov.au/re ... ection.pdf

Your Home Tech Manual
http://www.yourhome.gov.au/technical/fs410.html

WERS Site
http://www.wers.net/how-wers-works/selectingwindows

keilor_ob · Jan 27, 2011 10:30 am

Stay away from A&L I'm yet to explore there quality of product I have waited over 3 months to have my double glazed argon filled bi-fold installed and windows delivered. They seem to take your money but offer no customer support.

melbourne architect · Apr 18, 2011 10:26 pm

keilor_ob

Stay away from A&L I'm yet to explore there quality of product I have waited over 3 months to have my double glazed argon filled bi-fold installed and windows delivered. They seem to take your money but offer no customer support.

Did you get your windows?

melbourne architect · May 02, 2011 6:13 pm

http://forum.homeone.com.au/viewtopic.php?f=20&t=47112

dymonite69 · Jun 12, 2011 8:00 pm

Have you considered cellular/honeycomb blinds?

Greg M · Oct 19, 2011 9:10 pm

I have recently been to the Dowell factory in Bayswater where they have released the ThermLine range in both awning and sliding window formats. I met the designer and not only does the new profile look great but WERS have rated them as the best on the market. GJ Gardner are researching them very closely for some of their more upmarket homes in Mebourne Eastern suburbs.

Steve · Oct 26, 2011 1:51 pm

Local hardwood timber frames on double glazed windows provide no thermal bridging issues and are a far more environmentally sensitive choice compared to the all other options (such as PVC and Al), this is about sustainable building after all.....As Eccles rightly pointed out, it is most important to get your eve/solar pergoal design right to allow full solar access in winter and full shading in summer. Also allow for plenty of cross flow ventilation options in summer too.

Steve