Drive through Florida and you'll find an ample number of houses with exterior window shades. Across the country, in Palm Springs, CA, where the sun is like a Pittsburgh steel factory blast furnace, you'll see few.
Sun beating down on your windows is one reason why your house is so hot. Is this overly obvious? Maybe so; but if it's so obvious, why don't more houses employ exterior shades to prevent sun from reaching the windows in the first place?
Windows Are Losers (Energy Losers, That Is)
It's sometimes said that windows are thermal holes. What this means is that window-less walls provide the absolute best barrier against outside heat or cold.
No window--no matter the number of panes, type of interior gas, or low-e coating--can compare to the insulating effect of siding, fiberglass insulation, and interior drywall, all sandwiched together. The very minute you punch a window in a wall, exterior temperatures begin to influence interior temperatures.
Windows rapidly lose whatever kind of artificial climate you are trying to create in your home, and that's why we say that windows are losers.
Interior Blinds Help, But Not The Solution
Interior blinds are best for privacy, but aren't best for preventing the convection effect of sun blasting inside and heating up your home. Better is to catch the sun before that happens. Stopping the sun from reaching your exterior window glass is just one step, but an important step, in cooling down your house and reducing your energy bills.
Most of us don't want to live in a dark, windowless box. The second best option, according to the Florida Solar Energy Center, is to avoid having windows on sun-facing sides. This can be incorporated into house plans upon construction; or, if remodeling, you can remove windows, build over the gaps, and possibly re-install the same windows in a different area.
1. Hood and Solid Aluminum Awnings
They Are: Absolutely the best way to ambush the sun before it can hammer your windows, hood awnings are like hat visors for houses, but with side protection, as well.
Good: Unlike motorized awnings, fixed hood awnings are DIY-friendly. Because they are fixed in place, wind has to work that much harder to tear them from their footings.
Bad: They seriously date your house, as these types of awnings were used in great numbers from the 1920s to the 1970s. Faded, falling-apart aluminum awnings litter the U.S.South. Even in good condition, these awnings have a ponderous visual effect on your home's exterior.
2. Bahama (Alternately, Bermuda) Shades
They Are: Louvered shutters that have a long piano hinge at the top and tilt upward. Side arms are then set in place to hold the shades at an approximate 30 degree angle. When the shade is up, the louvers are horizontal, permitting people in the house to look outside.
Bahama shutters have two functions: keeping sun out and protecting glass from flying debris during hurricanes. Cost is about $300 for a self-installed Bahama shutter.
Good: Super-easy to install. Once you have the top track in place above the window, you have little else to do besides sliding the shutter in place, attaching the side arms, and screwing in the locking brackets.
Bad: If you like lots of light, these shades cannot be flipped all the way up. Also, they do not block light coming in from the sides.
3. Roller Awnings
They Are: Fabric awnings stored in a tube mounted above the window. Electrically or manually operated, these awnings unroll from the tube and extend to become a self-supporting (no vertical supports) cover for your window.
Good: They retract when not needed. It's possible to purchase awnings that cover the width of two or three windows.
Bad: Fabric will eventually degrade due to sun exposure. Flimsy shades can tear away. Even when retracted, roller awnings' storage tube remains, and may be unsightly.
4. Exterior Rolling Shutters and Sunscreens
They Are: Metal "gates" that roll down and completely cover the window. They look much like security gates used to cover up businesses in malls or on crime-prone public streets.
Good: Complete coverage of window. No sunlight will enter the house.
Bad: You are preventing sunlight from entering at the expense of your view. Because these shutters rest close to the glass, heat can build up between shutters and glass. Better for preventing glass breakage in high winds than for shading windows.