Yes, you’ve read all about passive solar design techniques and know what they can do to improve energy ratings for buildings. But these can only be employed at design stage, right? The simple answer is no. There is something you can do about that power-consuming house of yours!

The Rules of Thumb: What to Target?

Depending on your location, glazing oriented within 30 degrees of the south facing direction would be best suited for both daylight and winter heat. Proper shading should be incorporated to prevent overheating in the summer and still allow full sun radiation in the winter. North windows are important for natural ventilation in the summer, but should be reduced in size if possible, as they will lose the most energy in winter compared to glazing oriented elsewhere.

Apart from shading systems, installed glass properties are also important. Another recommended step would be to replace glazing in certain locations for optimal performance based on different exposures.

The prevailing climate should determine your choice and placement of thermal mass, i.e., building materials that are used to store heat. Some materials have the capacity to store radiated heat while it’s available and release it gradually as the temperature drops, thus acting as a moderator for indoor temperature.

This article mainly targets the details of proper shading techniques.

Step One: Define & Utilize Your Location

Search and write down your location’s latitude and longitude as well as your time zone. There are many websites that can help you do that like and

At this point, it would be time saving if you have blueprints of your house. If not, sketch a simple floor plan to scale, properly locating all existing glazing on it. Use a compass to mark the north direction on your plan. Mark and number the windows, then create a separate sheet listing each window’s dimensions and orientation.

Identify the hottest and the coldest months of the year based on local climate data, so that you can use those to determine your best window shading options.

Step Two: Visualize How Each Window Is Sunlit!

Now, did you think you would need to calculate all possible sun angle combinations year round? Wrong. There are many available freeware and shareware tools to help you do that. A personal favorite of mine is In the tools section you can find what you need to determine the best overhang dimensions for each window and visualize how each window would be shaded throughout the year.

Step Three: Design Window Overhangs and Louvers for Optimal Shading:

Your goal would be to determine the optimal shading device and its dimensions. For example, your quest should be to design an overhang extending long enough to provide 100% shading during the summer season but still sized and tilted in a manner that allows full winter sun radiation if possible.

Play around with overhang length and pitch as well as its height above your existing window. Aim for a shading percentage near a 100% in the summer, and as small as possible in the winter. You will find this most easily achievable with south-facing windows. Keep in mind that the sun’s altitude is increased in the summer as a general rule.

With west-facing and east-facing glazing however, you should determine your priority; Is it the heating season, the cooling season, or the overall installation cost? If you have some extra cash it would be wise to install a removable or revolving overhang system that can be eliminated for an entire season.

Another good option for west-facing and east-facing windows would be to utilize blinds. The sun rays would be near vertical on the window’s surface at a certain time of the day. A horizontal blind that is downward tilted during the summer would help reduce direct sun radiation and increase insulation while some day lighting is allowed. The same blind can be tilted upwards during the winter allowing the penetration of sun rays and daylight, while providing some insulation depending on its material. You can also use vertical blinds with fins tilted 45 degrees to achieve very good shading during the summer.

Step Four: Have Some Extra Cash? Check Out These Options:

At a later stage, you can make further enhancements like installing a solar chimney, or constructing an extension to your home at south-facing facades with folding or fixed glass walls (i.e. a sun room). These are two renovation suggestions that can be very beneficial if carefully planned in terms