The green post: how much should we spend to save?

How much will this 34 square home cost to run, heat and cool? It is a question that has been bugging me for a while.  We have built with green in mind as much as we could.  We have been given a 6-star energy rating, which I believe is the required standard in Victoria for new homes. A friend has quipped that it will cost me another salary to keep the bills paid on this new house. Thanks Ian!

So lets have a look at this in more detail. Six-star homes use 50 per cent less energy for heating and cooling compared with a typical 2 star dwelling. With our energy efficient appliances, we hope to save even more. Our old house was probably a 1 star home with all of the cracks and gaps to the outside world.energyratings

We really wanted double glazing but once I did the payback period, it was looking like around 26 years!

We tried to build in hebel – aerated concrete blocks – but as we are close to the beach we were required to keep the hebel in tip-top shape with a regular coating system to keep the salt off. It was looking – from a bit of research – like a little bit too much work longer term.

We do plan to get a solar system, but have decided to delay for 24 months. The price of 5kw systems are falling so fast that I’m expecting the pay-back period (even with declining feed in tarrifs) to be more attractive down the track.  A 5kw system was over $20,000 a few years ago. Today, around $5,000. A useful calculator I sometimes use:

The things we have done – and what the house comes with – to lower energy usage.

  • Large 600mm eaves
  • No down lights – not one!
  • Full LED lighting
  • Evaporative cooling upstairs only
  • Five star ducted heating instead of 3 stars, and added more zones for efficiency
  • Added an air lock to stop front entry draughts racing through the house
  • Added a wood firebox with a high burn efficiency
  • Added sarking to the roof
  • Light coloured roof
  • Recycled front fence and merbau deck
  • Solar hot water system
  • Water tanks for garden watering
  • Pergola to protect west window
  • Outdoor room shading to north
  • 100% edible garden (fruit and vegetable)
  • On-site composting of all scraps and paper products

I will hunt down some old bills of the old house and I look forward to comparing it to the new.  Some nice excel charts to follow.

What have you done to your house to make it a bit more eco?


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