Monday, December 1, 2008

Taking shape

Formwork for the thermally-massive living area floors is ready for a pour tomorrow, weather permitting. The ply underlay to the rear wing will provide a safe working platform during construction and provide added thermal and acoustic insulation on completion.


TB said...

Fascinating project, thanks for sharing it.

Question: have you made any projections about the total energy use within the finished home? You're obviously installing quite a bit of PV capacity and maximising passive design for thermal and lighting requirements, but how much energy do you think the house is actually going to need?

Emma Scragg said...

Thank you for your comments and questions. The first in our blog!

Yes, we have done some calculations of the energy consumption in the house. Unfortunately, greywater recycling systems, Ecovision monitoring system and pool pumps/filtration (despite the tiny size) use considerable amounts of power - almost 4kWh/day (more than my whole household use). My pessimistic estimate of the total energy consumption of the house is 15kWh/day. This can be lowered by the lifestyle of the occupants which I hope will be the case. We wanted to ensure that the PV's will at least cover the needs of the house with a bit of surplus to the grid.

Energy, water and gas use in the house will be monitored externally by Ecovision and the intention is that this can be observed by the public.

TB said...

Wow, 15kWh/day plus gas as well is more than I expected. How many occupants will live there?

Such a shame that swimming pools, even small ones, need so much energy.

What will the recycled greywater be used for? If the answer is gardening, will much of it be edible?

Emma Scragg said...

The greywater will be plumbed to the toilets and washing machine with any surplus going to selected garden taps. The water is treated to A+ standard, safe for hosing and sprinkling (and washing of bicycles...or cars).

There is 25,000L of underground rainwater storage dedicated purely to garden irrigation and pool top up so this would be used as the primary irrigation for vegie garden areas. All of the garden is edible - for human or wildlife consumption. We have a very detailed planting scheme.

Emma Scragg said...


According to the Queensland Government's Smart Housing sheet on energy use for Research House, average electrical consumption for Queensland homes (assuming cooking with gas) is 2009kwh per person (or 5.5kWh/day/person).
The Research House at Rockhampton, designed to be more energy-efficient, uses 5.3kWh/day - not much of a saving.

One of the big energy-consumers in the Hill End Ecohouse is its infrastructure. By treating its own water and reticulating rainwater, it is doing more than the average house and including energy consumption that would normally occurs outside the site boundaries.

A good evaluation of the Hill End infrastructure energy would be to work out how much energy goes into storing, pumping, treating and maintaining mains water and water treatment systems in the Brisbane supply per household.

Pools do use a lot of power and we have chosen a bigger system which will run easily on less power than the smallest pump/filter system.

TB said...

Great point about the use of energy for on-site water treatment which is handled off-site by the vast majority of homes.

That does raise the question about the resource-effectiveness of doing all that treatment on site rather than on a large scale. Clearly you're ahead on water use but materials and energy factors aren't so obvious. Would be an interesting study.

Will you be able to separate out the energy consumed by those systems from energy used in normal household loads such as lighting and entertainment?

Emma Scragg said...


The monitoring device will separate out energy use of pumps, greywater treatment, pool, lighting, power as well as water levels and consumption and gas consumption. We are keen to see the results.

Look at the information down the left hand side of the blog for more on materials and energy. We have also completed the Subtropical Housing Checklist, which I am trying to work out how to attache to the blog which elaborates on the whole design.