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exterior window shades to reduce heat

PostPosted: Fri Sep 05, 2014 3:08 pm
by lizzydiz88
Last summer when we had a heatwave, I tried out some window coverings as an experiment. The two south-facing windows are large, and have a cement driveway outside them, so a lot of heat radiates into the house. With one, I covered it with aluminium foil, on the inside, and the other had shade cloth hung on the outside (my kids whinged about how bizarre it looked, but I told them that the silver tinfoil looked kind of Christmassy :D ) Both of these methods made the area inside much more comfortable, so now I'm looking for a longer term solution.

I'm thinking of exterior blinds, but want ones that can be retracted, and also that allow some visibility out. I've been looking at Bunnings and online, and come across two basic types: shade cloth type material blinds, and ones that are made of a fabric that resembles heavy-duty insect screening. I'm wondering whether anyone has any experience of how effective either type is in keeping out heat, while allowing some visibility?


Re: exterior window shades to reduce heat

PostPosted: Fri Sep 05, 2014 5:11 pm
by Tracker
We went for reflective (perforated) roller blinds INSIDE... on our Nth facing upper windows..

I know that they are a compromise as they block what has gone thru the glass, but it's a compromise..

I had planned to apply a heat-reflecting window-film..

One thing with your foil... That is what the Pot-Growers use to block the bright lights from street view, and also to reflect that light back to the "Produce".... Ya wouldn't want the door bashed down at 1am.. :lol:

Re: exterior window shades to reduce heat

PostPosted: Mon Sep 15, 2014 12:36 pm
by ads
Hi Liz
We have the type of roller blind you show in the picture and it works well in blocking the sun from an east facing window. We put it up in November and take it down in March. I think these blinds are most appropriate for east and west facing situations where you want to block direct sunlight in summer, but you could still do it in the south. Since it doesn't project very far out it will give little shading to your driveway. Our blind is beige but you can't see much through it. see this blog post for a picture:

Have you thought of installing a tin shade horizontally above the window? This would block sunlight from the paved area and reduce radiant heat but would have no effect on vision through the window. The other option would be to lighten the colour of the concrete/paving.

Cheers, Adam

Re: exterior window shades to reduce heat

PostPosted: Mon Sep 15, 2014 11:26 pm
by lizzydiz88
Thanks, Adam, nice blog. I really liked the insulated dunny wall, very clever.

With the blind that you have similar to my picture, can they be rolled up and down while still in place? I really only want to put them down when it is particularly scorching.

The concrete is already pale grey, so no change possible there. Paving colour is important though - there is a small section of black sidewalk going over a bridge near my place, and each time I reach the black bitumen section, the immediate increase of heat is so obvious compared to the grey cement path.

Regards, Liz

Re: exterior window shades to reduce heat

PostPosted: Sun Sep 21, 2014 12:34 pm
by ads
Yes, they can be rolled up in situ. You simply undo two screws and roll it up. Then when you want it back down you pull it down and do the screws up. We only do it once a year because there's no view to block, but I'm not sure I'd want to do it daily...

When you first buy it you need to tension the blind once, be careful if you over do it they are permanently broken!

Re: exterior window shades to reduce heat

PostPosted: Wed Nov 12, 2014 2:55 pm
by lizzydiz88
window shade.jpg

Hi, thought I'd do an update on what type of exterior shade I chose in the end. It is a Windowware Shadecloth Retractable Blind (Classic Collection) from Bunnings. It is slightly see-through, but the bit I like is that the brackets at the bottom fold out when needed, and the blind hooks onto them, so it is easy to pull down just for particularly hot days. As to keeping heat out, the heat radiating into the room that I could feel before when standing inside in front of the window is now gone, so I'm happy with their performance. There is a five year warranty against UV damage other than fading, so they've only been up about a month, so I'll see how they last. I chose a pale colour so that fading wouldn't be so obvious, but I'm not sure how difficult they will be to keep clean.