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?


Got a question you want to ask without posting? Feel free to email us at metriconblog(at) 

5 thoughts on “The green post: how much should we spend to save?

  1. Great post E&M, I’m once again impressed with all of the thought you have put into having an Eco friendly home. Our approach to this was perhaps not so educated but we have the following features:
    – Light roof in paperbark
    – Rain water tank for exterior taps, washing machine and toilets.
    – Sarking to roof
    – Six star bathroom taps
    – Three star showers with airdrop infusion (highest rating available on the market)
    – LED lighting
    – Ceiling fans and east facing windows and entertaining/kitchen to cool with coastal winds
    rather than air conditioning,
    – Intending to add solar electricity in the future.
    – Five star gas fireplace for heating

    The air lock sounds like a fabulous idea for colder weather. Luckily we don’t have much trouble with the cold and the coastal breeze takes care of our cooling in summer. And wow no downlights for you! I’m very guilty of using too many (at least they are LED).

  2. Nice work chesterfieldbythesea! You’ve done well. Light roof will make a huge difference! We wanted to plumb the toilets and washing machine but the variation was pretty large! LED downlights are okay in my book! I suspect we will replace the standard taps (sic) with some more low flow taps in the future when the money tree grows back a bit!

    • Thanks! I’m really interested to start comparing bills once we are in. To be honest my choosing taps and showers was based on appearance and function at first, but using even our Nikles shower head is estimated to save about 70,000L per year. Amazing stuff!

      In NSW all new homes are required to have a water tank for toilets and washing machine to pass basix requirements. The cost was a necessary evil, but I hope we will make our money back over the years. Wouldn’t it be nice to have a money tree. At the rate we are going we will be using sheets as blinds when we move in haha!

  3. Pingback: Large house cost to run – fallacy | E and M's Metricon Adventure

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