Browse Forums Heating, Cooling & Insulation 1 Sep 29, 2019 9:16 am Currently undergoing a major reno of the top floor of a 1950s house in Sydney, double brick lower level, top level is partial brick veneer but mostly old vinyl panelling over timber framing etc (this will be replaced with Hardie weatherboard). Flat iron roof. LOTS of glass in the living, dining and kitchen area which we are converting into a single open plan space. Currently, due to the large amount of old thin glass and the flat roof our place absolutely cooks in summer. We are looking at standard laminated glass (6mm), low-e glass (viridian comfort plus 6m) or possible double glazed (Viridian Lightbride) to help make the space more comfortable (direct sun hits the glass in this area for large parts of the day) with the addition of two split system ACs (one large one small located at either ends of thew room). My question is - given we have the flat roof (we are having better insulation installed in ceiling as part of the reno) - is there any point in going for the more expensive double glazed option, or will it be overkill for a space that, due to the flat roof and non-brick exterior upstairs, will still soak up lots of heat through the roof and walls? My concern is that we pay more for the double glazed glass but have to crank AC all summer at much the same rate as if we had the other glass options, due to other factors mentioned. How much impact do you think the double glaze would have in this situation? What would you choose? The extra cost for the DG glass itself is $5000 which i am not worried about, it's more the extra installation costs. Thanks. Re: Help with selecting windows/glass for open plan reno 2Sep 29, 2019 11:28 am 40% of insulation benefit is from the roof. The rest is from the windows. So make sure you have high level insulation in the roof. (its generally quite cheap for an upgrade as well) However insulation isn't really as big of an issue when you have direct sunlight. Jake81 (direct sun hits the glass in this area for large parts of the day) This will be the biggest concern for heating. I can't remember the exact number but it was like each square m of glass is like a 2400w heater or something. As such the issue is from the heat from the sunlight coming directly through the windows and into the room. More so than the differentiation of heat transfer from inside to outside. (which is what insulation is best for.). Your best bet is to either stop or reduce the direct sunlight or the heating element of sunlight from entering your house. I do not know which window option is actually best for direct sunlight. Probably a question for the window experts. But on those trouble windows, i'd upgrade to whatever the answer is. Are there other things you can do? - Is it north facing? Can you extend the eaves so that it blocks the midday sun? (Eaves need to be 40% of the height from the roof to the bottom of the window to completely block out midday sun). - Roll down blinds on the outside of the window? - Else black out curtains with pelmets can help. (can be quite expensive) - Plant trees to block light onto windows? - If the house is on an angle of west/east. Then you could put side panels/eaves (not sure their name) on the outside to stop the morning/afternoon sun coming in. Edit: Another idea, is if you think a lot of heat is coming through the roof. Simply adding solar panels will help. It should drop the roof temps a few degrees as its blocking the sunlight. And it has the added bonus of paying for your air con usage. Perhaps a better alternative than paying 5k for the double insulation windows? (assuming its heat you are worried about and not nighttime cool) Re: Help with selecting windows/glass for open plan reno 3Sep 30, 2019 9:59 pm Thanks for your detailed response! The windows in question are east facing and north facing. Those are the ones soaking up heaps of the morning/midday sun. Extending eves is an option I’m exploring at the moment in addition to the new glass. The solar heating is a great idea and something I hadn’t thought of, thanks again. Neatep 40% of insulation benefit is from the roof. The rest is from the windows. So make sure you have high level insulation in the roof. (its generally quite cheap for an upgrade as well) However insulation isn't really as big of an issue when you have direct sunlight. Jake81 (direct sun hits the glass in this area for large parts of the day) This will be the biggest concern for heating. I can't remember the exact number but it was like each square m of glass is like a 2400w heater or something. As such the issue is from the heat from the sunlight coming directly through the windows and into the room. More so than the differentiation of heat transfer from inside to outside. (which is what insulation is best for.). Your best bet is to either stop or reduce the direct sunlight or the heating element of sunlight from entering your house. I do not know which window option is actually best for direct sunlight. Probably a question for the window experts. But on those trouble windows, i'd upgrade to whatever the answer is. Are there other things you can do? - Is it north facing? Can you extend the eaves so that it blocks the midday sun? (Eaves need to be 40% of the height from the roof to the bottom of the window to completely block out midday sun). - Roll down blinds on the outside of the window? - Else black out curtains with pelmets can help. (can be quite expensive) - Plant trees to block light onto windows? - If the house is on an angle of west/east. Then you could put side panels/eaves (not sure their name) on the outside to stop the morning/afternoon sun coming in. Edit: Another idea, is if you think a lot of heat is coming through the roof. Simply adding solar panels will help. It should drop the roof temps a few degrees as its blocking the sunlight. And it has the added bonus of paying for your air con usage. Perhaps a better alternative than paying 5k for the double insulation windows? (assuming its heat you are worried about and not nighttime cool) Re: Help with selecting windows/glass for open plan reno 4Oct 02, 2019 11:24 am Hi, In terms of reducing heat gain in summer, it would be worth reading up on the Energy Smart Manuals created by the SEAV in 2006. http://www.aprbuildingservices.com.au/C1_Energy_Smart_Housing.html There are several 'chapters' and I found them really useful when designing our new house. Here is a specific section taken from Chapter 5 (Windows) relating to reducing summer heat gain: Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ --------------------------------------------------------------------- Check our Homeone build blog here Hello! We have a very large open plan living room and wanted to get layout options, and furnishing ideas for this space. Currently there is only a… 0 9328 Cupcake.girl This really depends on your local council. Each one has different definitions and ways to calculate contributions. This is called a contribution… 1 3586 Hello It is good to have a planned bathroom reno to suit your budget and design, living for 10 years I think you need a bathtub 4 10378 |