Archive for the 'Background' Category

Sketchup

Thursday, June 22nd, 2006

We spent a while testing out house-design drawing packages with limited success – most seemed to be either full 3D solid-modelling CAD systems with a learning curve like the North face of the Eiger or trivial little 2.5D* “My new home designer” software that would limit you to little more than a simple box.

Then a post on a forum somewhere lead us to Sketchup. We downloaded the free trial (full program, limited to 8 hours use), watched the training videos and were just amazed by how powerful and yet easy to use it is. It’s not a full CAD package – rather (as the name implies) a 3D sketching tool but it’s so versatile and intuitive to use that true 3D models just grow before your eyes!

Nice as the interface is, the real killer app for us is the shadow generation – enter the location of your property (longitude and latitude), choose a date and let the program instantly calculate the sun’s position through the day. Drag the time slider across to see how sunlight and shadow change from dawn to dusk, or set a time (eg. noon) and watch how the sun’s position changes through the seasons. After seeing this, how could anyone attempt to design a passive solar house without it?!

To be honest we were a bit reluctant to get too attached to it at first because the purchase price for the full version was Au$705 – high enough to make us think twice! – but in the context of designing and building a new house well worth it. So back in March we went ahead and bought a copy… and at almost exactly the same time Google bought the company (@Last Software) for “an undisclosed sum”.

Now I see Google has released a new version, like most Google products free for personal use: Google SketchUp free. If only we’d waited a little longer! Oh well, it was worth it, and the price of computer hardware and software is falling all the time (not usually quite that fast though!). And perhaps the free version is limited in some way. I’ll install a copy on the laptop and find out…

I’ll be putting up some screen dumps of the Sketchup design, and the model file itself if anyone’s interested. Here’s a preview:

Sketchup model house design as at 18 June 2006
* 2.5D – Two and a half dimensions – ie. you can draw out the layout of each floor, set a ceiling height and stack the floors on top of each other. The problem is: what if you want different parts of the floor at different heights, or voids with windows extending up two storeys, or indeed anything vaguely out of the ordinary…

Dream block, Lake Macquarie, Australia

Saturday, March 18th, 2006

View 2

Not a bad view, is it? Unfortunately the view here is south-facing and we want to build a house that is energy efficient and takes advantage of passive solar techniques (among others), so we’re facing the wrong way! The block is also long and narrow in the north-south direction. Chris had already designed and built our current north-facing house (the ideal orientation in the Southern hemisphere) before we met. It is the first house that I have lived in that aimed to utilise passive solar techniques for energy efficient heating and cooling. I have been very impressed with the thermal comfort achieved for most of the year, compared to any other house I have lived in, although improvements could be made to make it even better. Since acquiring the property above, which will be a knock-down-rebuild job, I have developed a slightly rabid interest in environmentally friendly housing and ways to achieve good thermal comfort year round without breaking the bank. Chris is the practical half of the duo – he likes to point out why some of my ideas aren’t entirely feasible. He’s also the “big picture” person while I am interested in the minutiae – like adequate storage, practical bathroom, kitchen and laundry layouts and appropriate placement of the clothes line (not in the shade on the opposite side of the house from the laundry!).

Our challenge has been to design a practical house to suit our needs (we are only two plus a cat) that will maximise the view to the south, utilise northern solar gain, provide maximum passive summer cooling, which we have come to believe is more important than the winter heating issue, and not over-capitalise.

There is a lot of information out there about the basic techniques of energy-efficient house design, passive solar technology, etc, etc. There are even suggested solutioins if your orientation is not ideal – west or east facing for example. Unfortunately there is nothing that tells you how to have your cake and eat it too with a south facing building block in the southern hemisphere! Ideally you want to minimise south-facing glazing in this situation and maximise the glazing to the north, combined with other techniques like appropriate thermal mass, insulation and good ventilation. All excellent, apart from minimising south glazing when you have a view to die for in that direction!

Anyway, the idea of this blog is to work through our planning and design process, mostly in the hope that this will make it clearer to us, but also with the hope that others may have faced similar challenges and perhaps thought of ways of approaching this type of problem.

About SolarDreamHouse

Sunday, March 12th, 2006

Stunning 180 degree views over Lake Macquarie from high above! Perfect place to build your dream home!

Ok, enough of the real-estate agent hype – it’s a great location but the shape and orientation of the block doesn’t make for easy house design. It’s narrow, and the view is to the south (for readers in the Northern hemisphere that may sound ideal but here in Australia North-facing is good!). So how do we design a house to meet our requirements:

  • Take full advantage of the views
  • Minimal water usage (rain water tanks, grey-water recycling?)
  • Minimal power usage through good insulation, ventilation,  passive-solar gain and high thermal mass
  • ie. general solar and thermal efficiency for comfort without ducted reverse-cycle air-conditioning!
  • Photo-voltaic solar system? It’s under consideration but cost will be an issue, because…
  • We want all this without breaking the bank!

Using the WordPress blog format we aim to record the process of designing and building our new house, in hopes that by explaining our reasoning here we will understand it better ourselves and make fewer mistakes. And ideally you, gentle reader, will give us your feedback and comments to help us even further!

If you enjoy reading about our progress and perhaps find this useful in your own projects, please register and leave a comment.

Thanks

Chris and Fiona