All of the costs are now in and hence I can now compare the cost of the house with and without the sustainable and environmental features. Originally I though the cost would be about 15% of the normal build costs, but I have been surprised to find that the total additional cost for the features comes in at only 8.6% compared with a house without these features. And the payback period is probably less than 6 years in total for a much more environmentally friendly and warmer home. A no brainer.....
So what are the costs and the features.
Digital Self Heating House system. This is the core feature for hot water and house heating. A normal house would have had either a gas system ($13 -15k) or heat pump system ($15 -18k). Both systems would then have had ongoing running costs. The DSHH system had a cost of $30k but has no ongoing operating power costs for hot water or heating. The saving in power and heating costs gives a payback period of less than 6 years for the additional $15k up front cost.
The LED lighting system had an increased up front cost of halogen of about $5k and this includes the special feature light that we purchased. The running costs of the LED is expected to be one eighth of normal costs and this reduction significantly reduces the house electricity requirement. I have calculated that if we had installed halogen we would have had the equivalent of 5.6kW of lights compared with the 800W of LED light that we have installed.
The Photovoltaic 2.09kW system cost $12k and is connected to the grid. The payback time for this is quoted at 7.5 years, however due to our lower house load, no heating and LED lights I'm expecting that our payback will be less than 4 years. Time will tell, so follow the blog to see the results.
We have installed a Watersmart system for water collection which is used for toilets and outdoor taps and a grey water reuse system from showers, bath and basins for our in ground irrigation system. This cost $5.6k.
The uvPVC windows and doors cost the same as standard aluminium but with a green star 8 rating compared with the aluminuim rating of green star 2.
We have increased the thermal seal of the house with double insulation in the outside walls and with a fully insulated garage including the garage door. This will significantly improve the heating and cooling within the house. The additional cost of insulation was $1.5k.
All up the additional cost of the sustainable and environmental features was $39,148.
The total build cost excluding landscaping and section and the additional cost for sustainable and environmental features was around $457k.
The additional cost of the sustainable and environmental features is therefore 8.6% of the normal house build.
Based on the factory specifications and our known use from previous properties I'm expecting a pay back period of less than 5 years. Follow the blog in the months ahead to see the results.
