Friday, May 8, 2015

Build 101...living lightly on the grid - using solar panels to reduce your energy footprint

Having a light energy footprint is good good thing, good for the planet, good for resale (people are thinking about these issues more and more) and good for your wallet.  Win win I tell you.

When we built two years ago, reducing our energy footprint was an important part of the plan and we incorporated these energy saving feautures into our home:

  • Double glazed glass, insulated floors, walls and roof.  Insulation to keep us warm in winter and cool in summer
  • Windows designed to encourage natural airflow throughout the home.  
  • This works far better than I thought.  If we have been out on a hot day and the house has been shut up we open our bedroom door upstairs and a door downstairs and you can feel the cool breeze flowing down the staircase.  The whole house is cooled naturally in ten minutes.
  • Ceiling fans instead of an air conditioner.  
  • Solar panels to harness the great natural sunlight we all enjoy for free
  • A shaded central courtyard opening onto all our living spaces - provides a cool summer space which cools all our living spaces.

Did we survive without air conditioning? 
Its been three years and in that time Sydney has had record heat waves.  Did we survive without air conditioning?  Yes!  There were a few super hot days, but with the ceiling fans on and the windows open we were fine, even on the hottest, most airless of nights.

Anybody who has paid an air conditioning bill will tell you just how expensive that is, so designing a house that doesn’t need any has been a fabulous investment.  Investing in solar panels has been another!

Fitting solar panels
Fitting solar panels on our home was easy to do.  With a largely flat roof (we have a small incline to handle rain water) the panels were easy to position in a north facing direction and are not shaded at all.

Solar panels need to be correctly angled to maximise the energy you can harness.  The angle is different depending on your latitude, and whether you want to save energy in summer (for air conditioning) or winter (on heating).  A rough guide is your angle should be your latitude +10 degrees for summer savings, - 10 degrees for winter savings

You also need to make sure you install enough panels to make a difference to your power bill.   Looking back we could have installed double, but at the end of an expensive build we spent what we could afford.

These are all considerations that will depend on your property and budget, solar installation professionals can help you work through the considerations.

Are the power bills down?
Yes, perhaps not as much as I would have liked, but it definitely helps. 

At the moment we feed the power we generate back into the grid and are paid for the contribution.  This is not a winning deal for us as the amount we are paid is far less than the amount we are charged per unit.  Even though (personal gripe) the power companies can sell green energy for top dollar prices. 
I would prefer to store the energy we generate in a battery that we use instead of drawing on the grid, but the battery technology is still expensive and not necessarily efficient.  An investment for the future.

It’s very satisfying to check the meter on a hot day and see just how much energy we converted to power for the day!

Types of panel
We installed the tilted solar panels on top of our roof that you are probably familiar with.  They are on the top of our largely flat roof and we can’t see them at all which is great because they don’t interfere with the look of the house.
But if you have, or are planning, a tile roof, Monier produces a solar roof tile that can be laid as part of their tiled roof systems, incorporated seamlessly into the roofline.  What a great idea!  The efficiency will depend on the angle of your roofline and how much of it faces in the right direction but it’s definitely an idea worth investigating.

Having lived in our house for 2 years I can tell you that our west facing walls get blisteringly hot in summer.  We faced the house away from the west heat and only have a drying yard on that side.  On some summer days its almost to hot to go out and hang up the washing, it certainly feels hot enough to fry and egg, and the wall finish takes a pounding from the sun.  Imagine if we had clad the entire wall in solar panels – no maintenance and it would generate energy.  Perhaps a solution for the future

At the end of the day all these features have been very worthwhile, we have a house that lives lightly on the grid, and is comfortable for us and our pockets.  We should all be future proofing our homes for energy efficiency.

For  more in the Build 101 series: where I share my experiences to make your build decisions easier, click here.

Image inspiration via Houzz: top, bottom

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