Passive Solar? What, Why, and How

Why? In a nutshell, Harmony with the Environment. Passive Solar is an ages old concept whereby you make maximum use of Solar Effects for heating and cooling. This way you're not always fighting against the elements.


However, most Homes were built with other priorities in mind like developer constraints, business goals, existing roads, bylaws, building codes etc. Our goal is to help Homeowners transition to a more Passive Solar design to help reduce Heating and Cooling costs through their renovation process.


Since the house is already built, some characteristics can't easily be changed like house orientation, Solar access, and Climate. These limit what can be done. Therefore, each house is different and our customized modeling takes this into account.

On the PLUS side, you have free Solar energy gains to help with heating and cooling. You don't have to do anything except maybe open or close shutters or vents. It is a smart way to lower your energy bills and reduce emissions. It is also smart to determine the benefits to expect. Our program does that.

However, on the other hand, Solar is a low intensity energy source so you have to be more precise in collecting it, storing it, and keeping it. This means you will want higher insulation levels and lower infiltration levels, in order to keep the heat in. Also, if there is poor Solar access, like a neighbour or obstacles on the Sunward side, you'll have to focus more on keeping the heat in instead of collecting it.

Therefore, many references on the subject report the following typical Passive Solar rules of thumb:

  1. The long side of the house should run East/West to provide maximum wall area for windows to collect Sunshine.
  2. Most of the windows should be on the Sunward side.
  3. Shading is necessary for the Solar windows to avoid overheating.
  4. Sufficient thermal mass needs to be in place to store, and slowly release, the collected heat.
  5. Insulation levels should be high enough to keep thermal losses low.
  6. Infiltration should be low enough to minimize heat losses through drafts yet high enough for a healthy home.


The requirements outlined by R2000 (1980's Era), Passive Solar, and more recently Passive House and Net Zero, address these with ever increasingly tight standards and better technologies.
It is our goal to assist homeowners move their homes towards these standards as is practical in each case.