Rolling shutters greatly increase efficiency of windows

Q. My windows are not the most efficient. Instead of replacing them, I am considering installing rolling shutters for their efficiency, storm protection and security. What design features should I choose?

A. There are many options for making your windows more energy efficient, but rolling shutters also offer the other advantages of security and storm protection you mentioned. We have tornadoes here in Cincinnati so I am considering installing one over a large glass window. During a storm last fall, a tree branch almost broke the glass while I was sitting near it.

The actual energy savings from installing rolling shutters depends upon the type of window glass you now have and, to a less extent, the types of slat in the shutter. If your house now has double-pane windows, adding the shutters will about double the insulation value of them. With single pane windows, the percentage increase will be even greater.

An additional energy savings can be realized during summer because the rolling shutters also block the direct heat from the sun's rays through the windows. The shutters can be lowered to any position to allow in only as much light (and heat) as you desire.

Rolling shutters are extremely strong and secure because they operate similarly to a roll-top desk. Narrow slats roll up into a box housing above the window. The sides slide in vertical tracks on each side of the window making them very secure and relatively airtight when they are fully closed.

If you want security and privacy, but also light and ventilation, slightly raise the rolling shutter. The bottom of the shutter will not rise, but the slats will separate slightly exposing the interlocking flanges between them. There are narrow slots in the flanges which allow some light and fresh air through them.

Several materials are used for the slats: roll-formed metal, plastic or extruded aluminum. All are suitable for most areas. The extruded aluminum are the strongest and most expensive and are often used on large windows. The roll-formed metal ones can be filled with foam insulation for higher efficiency and rigidity. Check your local building codes for required materials and strength.

An important feature to consider is how the rolling shutter is opened and closed. The various options are a pull strap, a crank handle and an electric motor. Keep in mind, if the shutters are inconvenient to use, you will not close them as often as you should for efficiency or security.

For most smaller to average size windows, a pull strap is easy to use and inexpensive. Large shutters or ones from heavy gauge aluminum may be easier to operate with a hand crank. Electric motor operators are most convenient, but also more expensive.

The following companies offer rolling window shutters: AC Shutters, (800) 745-5261, www.acshutters.com; Roll-A-Way, (800) 683-9505, www.roll-a-way.com; Rollac Shutters, (888) 276-5522, www.rollac.com; Titan Security, (866) 691-3667, www.titansecurity.com; and Wheatbelt, (800) 264-5171, www.rollupshutter.com.

Q. We had central air conditioning added to our house about four years ago. I just noticed the outdoor slab has settled and one side is about an inch lower. With this tilt effect the air conditioner operation?

A. One inch does not seem like a significant enough tilt to cause problems. Most of the slabs the outdoor air conditioner condenser unit rests on do not have footers and many settle a little.

If the tilt becomes greater, have your cooling contractor check it. Depending upon the design of the compressor, a significant tilt can starve parts of the compressor from adequate lubrication oil.

• Write to James Dulley at 6906 Royalgreen Drive, Cincinnati, OH 45244, or visit dulley.com.