too-sunny window

How to choose the right solar shade

It’s time to seriously think about solar shades. Where I live, in British Columbia, Canada, the sun here is of equal intensity to Phoenix, Arizona, for cryin’ out loud. If you want to protect your floors, drapes, furniture and home cooling bill, you need to put something on your windows that will reduce the effects of the sun.  You paid a lot of money for all of these things, don’t be foolish and think an inexpensive off-the-shelf shade will give you the protection you need. You need solar shades.

Here is what you need to know when shade shopping.

Shades should have the “openness” factor listed on the label or sample swatch. This indicates how much of the fabric you can actually see through. If you took a piece of blackout fabric, (which you can’t see through and therefore has a 0% openness factor), and punched holes through 15% of the surface, you would be able to see through 15% of the fabric. This fabric would then be listed as having a 15% openness factor.  In this climate, a 5% or 7% openness factor is what you should look for.

In addition to this measurement, consider the Tv measurement, which indicates light visibility, and refers to how much light is being allowed through. I know this sounds like the openness factor but it isn’t. The Tv is affected by the color of the shade; a light-colored fabric lets more light through, a darker fabric lets less light through, but oddly enough, dark shades seem to be easier to see through than light-colored shades. Don’t know why, but they are.

The difference in view-through of light vs dark-colored shades.


Then you have the Ts, Rs and As measurements. These 3 numbers will add up to 100 and refer to the amount of transferred, reflected, and absorbed solar energy. This is a big deal.  For example, a dark gray solar fabric from the line of shades I sell with an openness factor of 5%, has:Ts12, Rs 8, As 80,  the light gray of the same fabric measures: Ts 27, Rs 57, As16.  The darker fabric allows less energy to transfer into the room, reflects much less, and absorbs a whole lot more energy than the light colored one. (It will feel much warmer to touch).  The darker one has a Tv of 21, the lighter has a Tv of 14, so the lighter-colored one allows more light through.

So, if you are shade shopping, decide what you need them to do. Write this down and buy accordingly. If the shade supplier can’t tell you what the ratings are on their shades you may want to consider shopping elsewhere.

This is a snazzy picture which illustrates how much view-through there is at night when solar shades are in place. These shades are made for blocking sunlight, they are not privacy shades,  and unless they have an openness factor of 0, you can see through them.blinds outside in


Here’s a real-life example. Not everyone has a magazine-ready decor. Sometimes it’s the sliding doors on a retired ladies balcony which needs help. We chose a dark color so she could still see out. This is a southern exposure window, and the temperature can get well over 100 degrees in the summer. It’s also a rental, and with a limited income there wasn’t an option for replacing the glass. And she wanted the heat from the sun in the winter, so a solar film wasn’t the answer, either.

solar shades

If you’d like to know a bit more about protecting your home from sun damage, zip over to this column. Lots of good info there about solar heat gain, and how to rein it in..

Solar blinds with industrial lighting

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