Energy positive houses
Yes, we do design and build energy positive houses. The graph above shows the electricity consumption from November 2014 to February 2015 for a family of four (Mum, Dad and two teenagers) living in an all-electric (no gas-connected) 8.5 star Jigsaw home.
Over summer this household used just 15% of the average electricity consumption of a typical four person household in Canberra. In fact, over summer they used just a quarter of the energy typically consumed by a one person household! It’s not just a great house in summer: in winter they used one third of the energy typically consumed by a one person household. What does the little graph on your electricity bill look like?
The graph below shows the seasonal energy costs for an average four person Canberra household compared to the cost of electricity used by this Jigsaw family plus the credits they are earning from their 4kW solar power system.
- The average four person Canberra household uses 5.8 times as much energy as this Jigsaw household.
- This Jigsaw household generates 3.9 times more energy than they use.
- Over the last year this household has saved $2,390 compared to an average 4 person Canberra household without a solar power system. As energy prices increase this relative saving will grow.
- With electricity supply charges factored in this household still has an overall electricity credit of more than $500 for the last year… yes, that means they have a negative annual energy bill!
NB. Occupant behaviour is really important for achieving results like this. Great, efficient design for climate and quality construction give you a massive head start, and solar power is a winner in Canberra, but how you live in a home and manage the house to regulate its temperature will play a big role in determining how comfy you are and how much energy you use. The phrase ‘solar passive design’ is a bit misleading… you may not need active, electricity guzzling appliances to keep you comfortable but you do need to manage, and operate, your house to maximise its performance. Something that this family is very committed to.
If you’re interested in the output and efficiency of their 4kW photovoltaic system… here’s another graph for you!