Dear Jim: My computer and VCR were damaged by voltage surges last year. Will whole-house surge suppressors work better than the cheap plug-in ones? Will they also save electricity as I saw stated in some ads? – Lynne H.

Dear Lynne: Whole-house surge suppressors are generally more effective than the ones which you plug into the wall and then plug in the appliance or electronic device. Almost every electric item in your home now has some type of sensitive electronic component which voltage surges may damage.

It is important to understand how voltage surges damage electronics. Everyone thinks of a huge surge, coming from a nearby lightning strike, that fries the electronics and this certainly can happen. Generally though, repeated smaller surges, which you are not aware of, slowly degrade the components and the insulation materials until the item malfunctions.

Voltage surges are often created when an electric motor switches off. These may come from a freezer compressor in a delicatessen down the street or from the refrigerator or washer inside your own home. The surges can range from just several hundred to several thousand volts in amplitude.

A combination of a whole-house surge suppressor (mounted on the circuit breaker box, under the electric meter or built into a circuit breaker) and plug-in models provides your best protection against damage from surges. If there is a direct lightning strike on your home, even the best surge suppressor may not help.

You will see many ads for whole-house surge suppressors ranging in cost from about $150 to nearly $500. There are differences in the level of protection they offer which you can compare by their specifications. Some also include a warranty (up to $25,000) to replace any items which are damaged by surges.

Don’t plan on saving much electricity from installing a surge suppressor as some companies’ advertisements indicate. There may be a negligible savings by reducing motor hysteresis caused by uncontrolled voltage surges, but your reason for investing in a surge suppressor should be protection.

The key specifications to consider are the maximum surge current, the energy dissipation and the clamping voltage. The more expensive models have larger and more MOVs – metal oxide varistor – to be able to handle higher surge current and dissipate more energy. A lower clamping voltage (the voltage where the unit starts to block the surge) is better.

If you have cable television, consider selecting a model with input-output terminals for the cable. Surges, often from lightning, can enter your video equipment and computer via the cable. Also use a plug-in model with telephone line surge protection.

The following companies offer whole-house surge suppressors: Control Concepts (800-288-6169, www.control-concepts.com), Eaton Electrical (877-932-9322, www.eatonelectrical.com), EFI Electronics (800-877-1174, www.efinet.com), Panamax (800-472-5555, www.panamax.com), and Square D (888-778-2733, www.squared.com).

Send inquiries to James Dulley, 6906 Royalgreen Drive, Cincinnati, OH 45244, or visit www.dulley.com.