In the article “retrofitting windows to conserve energy” I talked about using sheets of polystyrene to keep out the worst of the summer heat as well as the winter cold, but here in western Sydney during a western Sydney summer you need more. Our house is made of dark brick and when the sun goes towards the west in the afternoon it blasts straight onto the back wall and bingo – solar oven. Great to cook with but not so great to live in! The polystyrene sheeting does a wonderful job on the windows but if you put your hand on the inside of the western wall you can feel the heat seeping into the house.
Unfortunately my preferred option of insulating the western wall is impractical without ripping off the gyprock from the inside and putting glass wool or whatever inside then replacing the gyprock. A lot of work and/or a lot of expense, so I needed to come up with something else. My initial thought was to make a blind of some sort using shade cloth, but during discussions at the Permaculture design course that I did, another idea was floated.
It appears that matchstick bamboo blinds have many things to recommend them –
- They are made out of natural materials and so can be recycled or composted at the end of their life.
- Unlike shade cloth, little oil is consumed during their manufacture.
- They can cost one tenth of what a commercially produced shade cloth blind of the same size costs.
- They are easily available and ready made
- They are easy to fit, roll up and roll down.
- They let the light and air through while reducing the heat
- They come in a light tan colour that reflects the heat
So all-in-all, I thought why not?
We measured up the back of the house and decided to only get enough blinds to cover half the length, just to see how they worked and putting them up was fairly straight forward, drill into the bottom edge of the eaves and then screw in the three cup hooks that came with the blind. The wire supports that hold the blind itself could then be threaded over the cup hooks and the blind was in place. The blind is the width of the eave (about 30cm) away from the window and wall of the house to allow any breeze to move through and keep the house cool.
The day has been a hot one, good to see how the blind does its job and one of the first things that surprised me was the amount of light reflected through the blind into the house, the kitchen and dining room area actually seem brighter rather than duller, which I was not expecting. They do the job though and there is a sensible difference between the bricks directly in the sun and those in the broken sun behind the blind and as one would expect the ones behind the blind are cooler.
If there is a big wind coming the big hint is to roll the blinds up and secure them, or take them down entirely so they don’t get shredded and when winter rolls around I will be taking them down for storage too. Also remember that they are made of a natural material and if you roll them up wet and leave them that way it will shorten their life so dry them out first where possible and definitely makes sure that they are dry before removing them for storage.
