Letting the light (and heat) in sounds like a great idea until you live in a part of Victoria where the summer sun is beating down on your home constantly. However, passive design principles are not static and take all climate conditions and seasons into account to achieve best use of ambient energy sources. When you are working on a new build or making plans for a renovation, it is important consider a number of key elements in passive design.
Orientation is important in ensuring that your home makes the most of solar heat and natural light and ventilation. For instance, north facing windows are ideal for allowing in lots of natural sunlight regardless of the time of year. Passive design principles addressing both summer and winter months should be standard design elements in Victorian homes.
For rooms that receive less direct sunlight, choose materials with high thermal mass to maximize heat storage. Tiles and bricks for walls or concrete for floors are ideal materials for rooms that are not directly north facing. These rooms are heat traps and will help you save on your energy bills when that heat is released after the sun goes down.
While you want to take full advantage of natural sunlight, it is important to remember that it can get hot in Victoria during the summer. There are methods used to great effect by builders who understand passive design: Overhangs and shading. Knowing the relative position of the sun where you live, while taking advantage of shading will help you utilise available sunlight in the best way possible.
A builder who has experience with passive design will know how to incorporate an effective overhang and recommend other methods of shading such as deciduous trees. The objective is to allow plenty of sunlight to enter your home when the sun is low in the winter, and block out intensive sunlight when the sun is high in the summer sky.
Bearing in mind whilst the climate is warming, passive solar heating is still desirable in Victoria, but with more heat waves, etc, the future focus will likely change to shading and cooling. If you have summer living spaces you can make the most of the available sunlight by designing those rooms to maximize the amount of sunlight that the room receives in Winter and the opposite in Summer. Remember, too, that any thermal qualities in those rooms will dictate how much heat is retained in the home after the sun has long faded into the night.
These rooms will naturally absorb a lot of sunlight and heat which is then stored in materials with high thermal mass, so include ways to block out the Summer sun otherwise you will end up running the air-conditioning on high in the evening. Each room that allows light in should take account of the overall heat that is retained during the night. The purpose of passive design is to increase energy savings and reduce your carbon footprint.
You can read 100s of articles on letting light in as part of passive design but, without considering the location of your build relative to its surroundings, you will never get a complete picture. The pitch of the land, surrounding properties, and the space you have to work with will all play a large part in how you should approach passive design. Again, this is where hiring a qualified and experienced builder or contractor comes into play.
Basic principles of passive design will save you a considerable amount on your energy bills. However, a builder who can take additional factors that go beyond conventional design into account will fully maximize the potential of your build. Sometimes it pays to fork out that little bit extra for someone who can take full advantage of the passive sunlight that you home is likely to receive.
For more information on environmentally sustainable homes, please see the Australian Government’s Your Home site: http://www.yourhome.gov.au/passive-design