Insulation suggestions for West facing wall

~steph~ · Aug 16, 2011 9:02 am

We sit on top of a hill facing west. Our upstairs area gets very, very, very hot, as in sauna hot in summer. We are making a lot of changes to improve our energy efficiency including large roof overhangs, cross ventilation etc. However there is one bedroom wall that we can't do much with, it will be hit solidly by the sun from lunch till sun down, so we want to put some top notch insulation in the wall to fend off as much heat as possible.
The wall will have foam render, not sure on the exact name of the product, it is the styrofoam that you render over the top of, on the outside which already gives up some good insulation, but would like wall bats or something as well.

What would be the best?

eyspy · Aug 16, 2011 9:30 am

The highest R factor insulation you can find.

You never mentioned whether this west facing wall had windows or a view ?

No view then plant out with some tall shading trees. The principals of passive solar design are: Sleeping areas facing South, living North, very few windows to the East and as little as possible windows to the West, preferably none at all.

~steph~ · Aug 16, 2011 9:38 am

eyspy

The highest R factor insulation you can find.

You never mentioned whether this west facing wall had windows or a view ?

No view then plant out with some tall shading trees. The principals of passive solar design are: Sleeping areas facing South, living North, very few windows to the East and as little as possible windows to the West, preferably none at all.

Unfortunately our view (and therefore window) is to the west and the orientation of the block has us fasing east and west. North facing looks straight at a rock, south straight at a house! We can't put a plant there as it is on the second level with a roof directly below it.

One of the tradies, who is also building a home, mentioned something about a more fibrous insulation batt that is actually accoustic insulation. Are the accoustic ones better for thermal insulation? We are going to go for the highest R value we can get, however just wondering if there are particular brands/styles that are best for walls.

eyspy · Aug 16, 2011 10:07 am

~steph~

.... Are the accoustic ones better for thermal insulation? We are going to go for the highest R value we can get, however just wondering if there are particular brands/styles that are best for walls.

I am fairly sure that it all comes down to the R value on what works best regardless of acoustic qualities or otherwise, I will stand corrected if wrong. You could put a wind out awning that could be extended for the heat of the day then wound back in when not so hot ?

bashworth · Aug 16, 2011 4:07 pm

Put a highly reflective (80%+) tinted film on the window it won't spoil your view but will make a huge difference to the heat that gets into the room.

We had the same problem and got the local Tint a Car franchise in. The guy who installed it on a sunny day was amazed at the difference it made to the room within minutes of being installed.

Probably only cost a couple of hundred dollars and well worth it.

Chippies_Kid · Sep 19, 2011 10:21 pm

Check out aircell products. Don't forget you can have a combination of insulation. I'm planning to have (inside to outside) gyprock (or possibly some sort of internal plywood cladding , then a reflective layer reflecting inwards (that's to keep heat in during winter, then a gap, then bulk insulation R2 or 2.5 (polyester), then a gap, then one of the Aircell foilboard (I think it has some sort of polystyrene attached), then my shadowclad!

Ideally I'd be building in strawbale or hempcrete, with a natural render, wool insulation where needed, but hey, I'm not perfect!

Oh, have you looked at getting a screen/awning made for above the window with slats angled to keep out the summer sun but let in the winter sun?

Good luck - sounds like things will be more comfortable for you this summer.

lambchoppa · Sep 20, 2011 8:55 pm

The rendered polystyrene is a good product. You should also have reflective foil (eg bradford enviroseal, or air cell or similar, with an air gap (important) to reflect away the heat. Then, on the inside you should have r2.5 rockwool batts (these are the acoustic insulation). Finally, put a vertiscreen automated awning on the window and make it double glazed. This will give you a good result (better but more expensive than the tint).

Also, you could paint the wall white or a light colour.

~steph~ · Sep 20, 2011 9:30 pm

Excellent, thank you, will have a look at the aircell/enviroocell products. Great timing that this has come up again as we are gyprocking next week and will do the insulation this week!

Once the house is done we will also be putting an external blind on the window, but it is fairly small anyway, it was the wall I was mostly worried about right now as we are able to do something about it now, but not once the gyprock is on.