Tuesday, February 11, 2014

living lightly on the grid...designing an energy efficient home

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 reducing our energy footprint was an important part of the plan and we incorporated these energy saving features into our home:

1  Insulation
Double glazed glass, insulated floors, walls and roof.  Insulation to keep us warm in winter and cool in summer

2  Windows designed to encourage natural airflow throughout the home 
This works far better than I thought.  If the house has been shut up on a hot day, we open a door or window upstairs and downstairs and you can feel the cool breeze flowing down the staircase.  The whole house is cooled naturally in ten minutes.

3  Ceiling fans instead of an air conditioner  
Allows you to sleep with your windows open, which you can't with an air con, and they keep the mozzies off in summer too.

4  Solar panels 
To harness the great natural sunlight we all enjoy for free

5  A central courtyard that opens onto all our living spaces  
Creates a cool, shaded summer space.  Its a lovely private space that offers shelter from the wind and sun.

Its been two 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, and solar 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. 
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!

At the moment we feed the power we generate back into the grid and are paid for the contribution.  This is the standard deal and my only gripe is that we are paid far less per unit than the amount we are charged per unit, even though the power companies can sell green energy for top dollar prices.  
I would prefer to be able to store the energy we generate in a battery and draw on that energy instead of the gird, but battery technology is still expensive and not necessarily efficient.  I am watching this space, the moment its worthwhile I will be holding onto all my green energy myself. 


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, 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 is 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.

A comfortable home with a light energy footprint
At the end of the day the combination of these features has been so worthwhile.  
We feel we have made good choices for the environment, as well as choices our budget could manage.

The house has a really stable ambient temparature.  It stays pleasantly cool in summer without needing aircon, and retains the heat we do spend on in winter well.  In a world where energy costs are expected to increase
 and create a very comfortable and energy efficient house in both summer and winter.   The combination of them all, plus the solar panels, have set us up for the future.

This post was written in collaboration with Monier, but all opinions are, as usual, my own.


1 comment:

  1. Some very relevant points here, another win-win situation is investing in a smart thermostat. Systems like Nest are a great way of saving money but obviously there's an issue with privacy with Google's purchase. A nice solution is http://www.heatgenius.net they use radiator sensors to recognise when a room is unoccupied and focus on managing the heat on a room by room basis. It's really clever and can save you loads of money.

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