Passive house and passive solar - what these buzz words really mean

Outside of any certification programs, the commonly accepted definition of a passive house is one that minimizes its operational energy demand through building design and orientation.

The concepts of passive solar heating and cooling

There is a bit of chatter in the construction world lately about passive house contruction, and that is a long overdue conversation. The most important thing to realize about passive heating and cooling is that it should not be an all or nothing technique; ideally it would be the first thought for every home, office building and even dog house you plan to build.

While having a home rated by any performance scale (like Passive House) is great as it draws attention to advanced techniques, smart buiding practices is not an elite club you that you should either commit to or feel excluded from.

Passive heating and cooling is simply a matter of determining where the sun exposure is, and trying to capture and keep as much of that heat as you can in the winter while keeping it out in the summer. This may seem like a tall order, but the seasonal position of the sun conveniently serves this end. In the winter the sun is low and will reach far into your house, in summer it is high overhead and easy to keep out.

The first thing to understand is that there are two kinds of solar collection in home design - active and passive. An active solar home has an expensive array of wiring, panels, pumps and other moving parts that will eventually, without

Passive solar on the other hand is simply common sense. Just figure out where the sun is, and point your windows at it. You can pick up a lot of free heat, and if you plan your shading properly with overhangs and window layout, you can help keep it naturally cool in the summer.

Proper shading prevents overheating with passive house buildings
Proper shading prevents overheating in summer © Ecohome

Other shading techniques besides overhangs can be effective, for example interior blinds or curtains, even trees. As illustrated by shadows on the house pictured to the right, mature deciduous trees can offer great shade in the summer, but lose their leaves in the winter allowing solar heat gain.

Of course this is only the bare bones of passive heating and cooling, and you can obviously go further into it with building envelope design, but it costs nothing to take the first step towards 'passive house' design which is just to think about it and in some capacity factor it in.    

For new home construction, people are often concerned about the added money it will cost to hyper-insulate a home. Try to think of your insulation more as something that will save money rather than cost money. Aside from monthly savings on utilities and a greater future resale value, putting more money into insulation means putting less into heat distribution systems.  

While renewable energy sources like solar panels and wind turbines are essential for creating a sustainable and secure future, in an ideal world our homes would be well-insulated and properly oriented so that they could be heated with little more than a hairdryer.

Natural heating and lighting means better quality of life, and makes financial sense as well. For little or no cost, instead of sitting in a dark room with a heater on, you can bask in the bright light and free heat of the sun. That, in a nutshell, is passive home design. And it can cost you absolutely nothing.

So don't be intimidated or dissuaded by the implied requirements of rating systems; passive home design dates back thousands of years and can be applied to pretty much any building.