As noted in my previous green home cooling post, the most important part of cooling your home is to stop excessive heat buildup. The most effective way to do this is by good use of shadow to block the Sun’s heat.
The most important parts of your home to shade are the windows. This is where the most of the Sun’s heat will enter your home if left unshaded.
The practicalities of using internal curtains and blinds for shading your windows – when to do what, and so forth – was discussed in Great habits for green home cooling.
Here’s a quick look at the different types of ’shading devices’ and how they’re best put to use:
- External shading is better
Shading your home with internal window coverings will certainly block a decent amount of heat – up to 65% – but external shading is more effective. Up to 95% of the heat can blocked by simply putting the ’shading device’ outside. - Curtains are better than blinds
Blinds will let more heat through than curtains. For extra performance, there are thermal-lined curtains available. - Brightly colored window coverings are better
Brighter colors reflect more heat than darker colors. As an added bonus, brighter colored curtains will let more light into your rooms, while still blocking heat. - Hang window coverings close to window
This inhibits air circulation across the window, preventing the air from getting heated. - Vertical, moveable window coverings are best for east and west windows
As the Sun moves across the sky, the amount of sunlight falling upon your east and west facing windows will vary through the day.In the morning and the evening, the Sun will be almost directly above the horizon, radiating its heat almost horizontally onto your windows. To effectively shade them, you need vertical window coverings like curtains, blinds or shutters.
Whenever the Sun isn’t shining directly on them, you can open these coverings to let light and air in.
- Horizontal overhangs are best for equator facing windows
The Sun will never hover around close to the north or south horizon. It will always shine down on your home from an angle, relative to these directions.Therefore, horizontal overhangs like verandas, awnings and pergolas are the best for shading your south facing windows (or north facing windows if you’re in the southern hemisphere). Overhangs will block heat while still letting daylight in.
I’ve left a whole group of ’shading devices’ out of this post on purpose: Trees and plants and everything else in the immediate vicinity of your house. Those things are getting their own post later in the series.
The next post in the green cooling series, however, will deal with how you choose the best windows for your home – seen from a cooling viewpoint.
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This post was tagged with: air conditioning, cooling, energy efficiency, energy saving, heat buildup, home cooling, house cooling, indoor temperature, saving energy, shade, shading, thermal lined curtains
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