Sunday, May 30, 2010

9.1 stars ... wow!

Okay, so a few people now have suggested I blog on building our 9 star home. Here goes! I hope some of you actually read it. :)

When we started out on this building gig, I didn't realised how rare 9 stars actually is. So this blog is partly about inspiring people, and also about sharing some of the thinking we've done along the way. If you are looking for info on sustainable building, then there will be some stuff in here for you. But I'm mostly going to focus on what we've taken into account, and the difficulties, compromises and struggles we face in building our home. For technical stuff, I very much recommend you visit:

I am starting to blog today because yesterday we received our official certificate: our house will perform with at least 9.1 stars worth of energy efficiency. For the techies who are reading this post, the stars translate into the following area adjusted energy requirements:
13.8 MJ/2 per annum for heating
7.5 MJ/2 per annum for cooling.

Cool, huh?

We also received little graphs that show indicative temperatures in all liveable rooms in the house for every day of the year. We have a blue line showing outside temperatures and a red one showing inside.

The graphs are impressive, although some are still a bit worrying. On the up side, in the main living area (open plan lounge/dining/kitchen) temperatures will mostly hover between 18 and 24 degrees, and our upstairs space is going to be delicious in winter. But in summer, whilst the house will be quite liveable almost all the time, on the very hottest of days, it's still going to be warmer than we might want.

The rating system only takes account of permanent fittings, such as our windows and reverse brick veneer (more on them later). We are also planning to instal an rectractable awning on the west side, and blinds with R values of between 0.63 and 0.78, depending on the window. These should make things a bit more comfortable. And we have one downstairs bedroom that should be quite bearable even in the worst heat ... so we can decamp there if we really need to (but obviously I'd rather not).

We were going to instal a reverse cycle air conditioner in our lounge, but with our 9 star certificate in hand, we have decided to live in the house for a while and decide then whether we need any artificial heating or cooling.

Okay, that's it for this first post. A heads up on how I plan to bring my dear readers up to speed with our project: the next few posts will introduce us and the basic features of our house, and after that, I'll use whatever is happening on site as my theme for the post.




Anonymous said...

Hi Elizabeth - any pictures of progress? It would be lovely to see the shapes you talk about - and the floor plans, if they're eaily added.

Anonymous said...

9 stars in Melbourne means 25MJ/m2 in heating and cooling.

This would suggest that a 200m2 house will require 1/4 tonne of wood or $32 of gas heating to keep it between 18-21 degrees all winter.

Anonymous said...

Hi Elizabeth,

Where did you get your daily graph from. Was it part of your energy report or did you have to ask for it specifically?


Elizabeth said...

Hi Anon

Our designer/builder provided the daily chart the the design process. That showed a likely range of temperatures based on conceivable outside temperatures (I have no idea where those come from, but presumably they are drawn from local climatic data). The chart showed us that there were going to be some extremes of temperature - especially upstairs - and helped us to decide whether and where to add thermal mass to the house.

I don't know if these charts are standard from all energy raters. If you are getting a price from someone, I would ask them what it includes.

Best wishes