I had a reality check today when I calculated how much per slab of Ceasarstone and how many we would need. A bit ambitious and I am definitely going with tiles now which will work with the underfloor heating. What a shame....back to reality.

@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.

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- Any wood fired heating we have would be purely run with wood from our farm, as opposed to buying anthracite. We would really like to have woodfire doing at least two jobs, i.e. cooking and heating/heating and hot water/cooking and hot water (as we are under the impression that solar hot water would not be enough in winter??). There's nothing like lighting a woodfire to keep your house warm, except for the great big hole in the insulation that it causes. As beautiful as they are (and I'm a massive fan of open/wood fires), they are pretty bad when it comes to ceiling penetrations. A lot of insulation is lost by having an open fire, a wood heater not so much, but still bad enough. For heating, the best advice I can give is this. You need a battery storage system! Then whatever type of heating you go for, you won't run out of energy for your cooking, cooling or anything else you won't to run at the same time. I believe this is a necessity, not to mention a very smart investment. If you want to be off grid, then be completely off grid. I personally don't believe in still being connected to the grid and having the energy your home creates, sold back to you for an absolute pittance. If you invest in a good battery set up, it'll last you up to 15 years and you'll have never have to worry about heating or cooling. I visited a house about 12 months ago that was off grid for power. They purchased an induction cooktop and electric oven, that way the idn't have to worry about refilling gas bottles or having a gas bill come in either. They didn't have the smartest idea when it came to lights as they were still using halogen's, but even still, their battery system never went under 80%. Even during winter, with two teenagers, and a couple of plasma tv's, playstations and all other sorts of electrical goods that they used. They were never too careful so as to make sure they had power in reserve. They just lived life and if they needed to make adjustments, then they could've done. But they didn't need to. That was all done with a 5.5Kw/H system. You'd be surprised how well solar hot water works. It just depends on the type of system you get. Again with battery backup, you won't need to worry. - We are planning to insulate the slab, but have not gotten as far as deciding what product we would use, are there several different products like the one you described? We do plan to have polished concrete flooring throughout the entire house – with the possible exception of bedrooms on the south, if absolutely necessary they will have carpet. I know it's probably more expensive, but I would recommend the Kingspan K3 Floorboards. It is a brilliant product and I recommend it to be used in all my jobs. The effect it has on an energy rating is massive. Depending on the layout and orientation of the house, just by adding slab insulation, I have noticed an increase of almost a full star difference in the rating. So that's from 6 star compliance, to 7 star above average. Here is the product site: https://www.kingspan.com/au/en-au/products-brands/insulation/insulation-boards/kooltherm-k3-floorboard - We will also be aiming to have the optimal amount of glazing for solar gain (and prevention of heat loss). I still haven’t worked out why I can’t upload a picture of our plans, but will do ASAP as we would love to hear feedback on our plan. As for the layout, you just need be mindful of window sizes and orientation. If you have the time before you build to play around with a few different variations of your plans, it might be a good idea, as just by changing a couple of small things, it can give you large benefits. One of the main focuses I have with my business is to help people such as yourself utilise the energy rating software to make small changes at the design stage, instead of just using such a powerful tool at the building permit stage. By then it's too late to make any significant changes. Just keep that in mind. It's a small price to pay to know that your house is going to be as energy efficient as it can be. If you want to, feel free to email me the plans and I can give them a quick look for you. Just to give you some quick advice on them. Giuliano green design & consulting