@Karen Hodge, I hear you!! Sometimes I think the estate agent should carry quite a bit of the blame actually. If they do their job correctly like you see in the adds on TV, they should bring these discrepancies to the attention of the sellers, stand on their morals and say if you can't get it better than this, then you'll have to find someone else to sell your home!! I know you can't make everybody "house proud" but the saying "do unto others" springs to mind. I bet if these same people bought a house not up to scratch, "a current affair" would hear about it but they don't think it wrong to simply walk out on a house that isn't being left nicely for the next family!! I have some friends that recently sold a house in Essendon, Melb and whilst the buyers were back and forth selling their own home, my friends kept watering the plants and even did things like painted out the wardrobes because of the scuff marks made over time!! They cleaned the entire two storey house from top to bottom and finished by mopping the floors as they were exiting. The buyers were so taken by the entire home, they bought it with almost all the furniture that my friends had in it!!

Hey Sally, This is from the ‘Thermal Mass in Summer’ section from our website, "With correct eave overhang on the North of your building & thermal mass being shielded from direct solar gain we can control the increase in the ambient air temperature of the building. During the day heat gains from external temperature, the occupants of the building, and any electrical lighting and equipment, is absorbed by the exposed thermal mass of the building and releases stored cool within the thermal mass, thus limiting the temperature rise within the space to be within acceptable levels for human thermal comfort. By the end of the day the thermal mass of the building has in turn warmed up, and now as external temperatures reduce the heat can be released and the thermal mass cooled down ready for the start of the next day. However this "regeneration" process is only effective if the building is ventilated at night when the external air temperature has dropped below the internal temperature, to carry away the heat that has been absorbed during the day. This can be achieved through naturally ventilating buildings (opening windows etc.) or the use of automated ventilation systems. This reduces or totally eliminates the need for artificial cooling systems to be installed, thus reducing the overall energy consumption of the building to attain a comfortable living environment." When temperatures do not drop at night for 3-4 nights, our houses are still far more comfortable than outside, warmer than it would be if night ventilation could be achieved, but still a comfortable temperature. In our house we just use ceiling fans during those in-between days! We find that even when it is warmer in our houses in prolonged hot periods than it would be with air-conditioning, the quality of the air and feel of being inside the house is much nicer than what it would be with the everyday use of an air-conditioner – not to mention benefit that not using air-conditioning has on the environment. Hope this answers your question :)

Gal will go grey (mid to dark grey) over 12 - 18 months. Initially VERY bright. The energy absorbed changes accordingly, from sub 5% absorbed to ~35%. Zinc maintains brightness for longer, though still suffers some dulling. Say 5% to 15% over time. This can be avoided by coating with a product called 'Sharkhide' metal protectant, used to stop aluminium boats oxidising. For there reasons many councils will not allow zinc or gal roofing (visual amenity, reflection issues), while making the houses more prone to requiring summer aircon at the same time. Surfmist Colorbond starts around 9% absorbed. If purely for energy reasons, a light colour might be the only option. If going dark, I would suggest at least doing the 'less aesthetically important' sides and rear in a light colour. Your call. If you go all dark, ensure you have good roof space ventilation for the summer that can be closed in the winter, and lots of well installed ceiling level insulation. Spray foam is more reliable over time than batts, see Spray It Solutions or similar (they have the Formaldahyde free Canadian Icenene foam).

@wayne For hydronics talk to Gary Flood at the Enter Shop. They are in Melbourne but he has installers everywhere. http://www.enter-shop.com.au/ Alternatively Alex at AJs Plumbing http://www.ajsplumbing.com.au/ We generally do in-slab hydronics but have also done it inside a rammed earth wall (at our office so feel free to come and look) and underneath a timber floor (several times including in our office). Insulation is critical. In a slab make sure you insulate the slab edge as well as the underside. When we talk of hydronics we generally use heat pumps to create the hot water (it's free to run if powered by PV). You mentioned wetback stoves (wood powered heating). In my view timber is only a viable option in rural settings. In (sub)urban settings the particulate pollution is a serious health issue and there is a fair chance that at some stage woodstoves will not be permitted by urban Councils. You finished by talking of ducted air conditioning. Regardless of the technology used to generate the heat/coolth, ducted systems are inherently inefficient and, in my view, should be avoided at all costs. The heat pumps can be great but the principle of pushing heated air around requires pump energy (you have to move large volumes of air). Almost all residential installations have flexiduct (not rigid as in commercial offices), the ductwork (aside from a study showing 80% of them did not meet the Australian Standard insulation code) due to its flexi-nature has lots and lots of curves and bends all of which increase the need for pump energy. This is why is it not possible to get a rated systems as you can with a split system; it is totally dependant on installation quality. You also need to be mindful of condensation issues in ductwork as heated air passes through relatively cold roof spaces, again quality of ductwork can be a big factor here.