Hi everyone,
First time posting so please go easy on me. It's been really interesting reading some of the feedback posted on this website in the past regarding solar passive design and I was keen to get some feedback on our design for a new house in north Brisbane. Over the past couple of years I’ve been reading resources online regarding solar passive design (spent a lot of time on yourhome.gov.au!), and whilst a completely green architecturally designed house is out of our price range we still would like to incorporate elements of passive house design with our chosen builder in order to reduce the amount of mechanical cooling required in the summer months whilst making the house generally liveable without mechanical heating/cooling for the remaining months of the year.
Background: My partner and I have done the full circle with regards to our forever home, initially living in our renovated 1950s 2-bedroom austerity Queenslander (~70m2) before news that our family would be getting an additional member in the not-so-distant future. As I work from home (and my partner is considering working from home as well in the future) we considered a further renovation (raise and extend), however the cost seemed comparable to buying new + we weren’t keen on the additional stress that can sometimes come with a reno on an older house. We looked to buy existing in the area, however after a few months of looking concluded both that the value on the market was poor and we really liked the location of where we currently are so have now decided to ride the knockdown-rebuild train.
After having a disappointing experience with a volume builder, we have engaged with a custom builder who, whilst not a solar passive speciality builder, so far has been flexible in design (such as stepping down the slab to suit the slope of the block). Our basic design brief was this; 2 x office spaces with one flexible enough to become a bedroom for an aging parent in the future, 3 x bedrooms + 2 x living spaces. The proposed house is orientated NNE to the rear (~17deg off north), with the house/block unfortunately longer on the East-West facing (40m x 16m).
As far as solar passive design elements, they’ve really just been things that I’ve provided as requirements/extras to builder, which is why I’m really keen to get some feedback here. We’ve tried to face all living areas to the rear of the property (i.e. NNE) as much as possible, and have decided the home offices can take the “solar gain” hit, positioning them at the front of the property in the South-West corner. We’ve tried to reduce the amount of glazing on the WNW face of the house, and where glazing does exist on the WNW we have asked for double glazed windows. Whilst there’s a lot of glazing on the eastern side, we’ve asked the builders to spec a low SHGC window tinting to try and counter act hot bedrooms in the morning (we also figured eastern facing bedrooms as we like to get up early, and these rooms should hopefully be cooler at night?).
Whilst it’s not on the plan, we’re aiming to put a rain water tank in the rear NW corner to protect the alfresco area from the afternoon sun + capture rain water for use in the yard. As well as this, I want to try and investigate using this water as grey water for use in the washing machine and toilets, but it’s not something I’ve engaged the builder with yet as I’m not sure what sort of extra cost this would add?
One area I’m really keen to get some feedback on is with respects to insulation; most say the more the better, however it’s sometimes contradicted by recommendations for Zone 2 climate stating that lower thermal mass is good for dissipating heat faster at night… but I guess that would depend on the night time temperature and the difference between the indoor/outdoor temp? I’ve made some recommendations to the builder as I thought their default insulation was too low, but I’m pretty lost with this one.
Would love to get some feedback, cheers!
Alex
https://500px.com/photo/1056317608/front-render-by-little-russ
https://500px.com/photo/1056321393/site-layout-and-orientation-by-little-russ
https://500px.com/photo/1056317612/ground-floor-layout-by-little-russ
https://500px.com/photo/1056317611/first-floor-layout-by-little-russ
https://500px.com/photo/1056317607/front-rear-elevations-by-little-russ
https://500px.com/photo/1056317610/eastern-elevation-by-little-russ
https://500px.com/photo/1056317614/western-elevation-by-little-russ