I don't agree. Josh Byrne's house is 9 star or so I think?
10 Star NatHERS energy efficiency rating
It has:
- Double brick construction on a concrete pad.
Only for part. The rest is reverse brick vaneer
- Only one double glazed window - the rest have double curtains and pelmets
Keeps costs down but doesn't compromise the thermal performance of the house
- Cavity insulation is simple foil backed foam with ventilation on both sides - none of these ridiculous foam filled cavities
- Has major north facing glazing with minimal north facing eaves - because it works.
Agreed, although the north side is planted with deciduous vines which provide shade in summer and sun in winter.
- Has a solar system to keep the sun off the roof.
True. I would like that at my house.
But I totally agree that the star ratings are up the creek. Don't like the rating someone has given you? Just find someone else to do the calculation until you get the right answer.
Agreed and there is no national standard to star ratings. He used NatHERS. I have also seen Green Star. How on earth could you compare them?
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In a mediterranean climate, thermal mass, window placement, ventilation and cavity ventilated bricks are most important - convection and radiation protection trump conduction insulation by far in the Perth real world but you won't get a computer model to tell you that. Putting ground insulation is completely unnecessary if the sun gets to the slab in winter and is kept off it in summer.
I agree with the first part of your statement but I'm not sure if there is no computer model. My understanding is that Josh and the designers used those exact principles and computer modelled the design, which indicated where double brick would be beneficial for thermal mass and where reverse brick vaneer would be beneficial for it's insulation properties. Sorry, I didn't pick up all of the design process, but my understanding is that it was extensively computer modelled prior to building.
Plant a grape vine over all that north facing glass with no eaves and you will be perfectly protected from the reflected summer radiation. It's really not that hard...
That's exactly what Josh did. The performance data confirms this approach defintely works. That's great in summer but in winter, more thermal mass is needed. That's why they put double brick to the north, where thermal mass is needed in winter and reverse brick vaneer to the south, where more insulation is required year round and thermal mass isn't as important.
IMO double brick and concrete slab construction remains the most practical and real world energy efficient construction method available for Perth, provided it is designed and utilised correctly. Which of course, is very rarely the case - but of course that can be changed with some knowledge of simple physics. Oh - and it is still the cheapest.
Reverse brick vaneer is more energy efficient where used correctly as mentioned above. In Josh's design, double brick certainly has it's place and so does reverse brick vaneer. I note the house is a real world, practical example of a Perth house built by a local builder for no cost premium over double brick. I know non-double brick upper stories are way cheaper in Perth than double brick. 101 residential and Ben Trager are some of the cheapest two storey builders in Perth partly because of the cost savings of EIFS upper storeys.