Dear Jim: I want efficient outdoor lights for entertaining, highlighting my gardens, and security. I plan to install them myself to save money. Will low-voltage lights increase my electric bills more than standard ones? – John E.

Dear John: Most low-voltage lights use the same basic bulb technology as standard bulbs, so the efficiencies are similar. The best method to reduce your lighting cost is to limit the amount of time they are on by switching them off when you are not entertaining or viewing your gardens. For security, consider using motion-sensing lights for a great savings.

The key advantages of installing low-voltage lights as compared to standard bulbs are the ease of installation, low wattage per fixture, small size, and wide range of decorative styles. Unless you are very experienced with electrical work, safely installing standard 115-volt wiring outdoors can be a challenge.

Low-voltage lights operate on only 12 volts of electricity. This is very safe and will not even shock you if you touch the bare ends of the wires. For this reason, the wire can be run along or under the ground without the risk of being shocked. Most standard wire should be run through conduit for safety.

A low-voltage lighting system includes the long wire, the individual lighting fixtures and the transformer. The transformer is plugged into a standard 115-volt outlet and it reduces the voltage to safe 12-volt d.c., or direct current, power. The maximum output wattage is listed on the transformer and varies with the transformer model.

It is important not to exceed the transformer’s maximum wattage output or it will fail. The wattage of the bulb in each low-voltage light fixture will be listed on the packaging and in the instructions. A 100-watt transformer can accommodate up to nine 11-watt light fixtures.

Most transformers have a built-in timer to switch the lights on and off automatically. Inexpensive low-voltage lighting kits use plastic fixtures.

The highest-quality, most durable lights use metal fixtures. These are very decorative and some include real etched and stained glass. These are more expensive, but they last for many years. Decorative real wood ones are also attractive.

Since you want to install the lighting system yourself, compare the types of wiring connectors. The two-part designs, which slide over each side of the wire and snap together, are easy to use. Snap-together lighted plastic simulated brick edging is also easy to install.

Your other do-it-yourself lighting option is a fiber optic system. This uses a 115-volt bulb in the projector box. Fiber-optic cables carry the light efficiently to the small lighting fixtures so no electricity has to flow to each one.

The following companies offer low-voltage lights: Argee Corp., (800) 449-3030, www.argeecorp.com; Idaho Wood, (800) 635-1100, www.idahowood.com; Intermatic, (815) 675-7000, www.intermatic.com;

Nightscaping, (800) 544-4840, www.nightscaping.com; and RSL Lighting, (800) 677-6811, www.rsllighting.com.

Dear Jim: I am trying to compare the operating costs of several different heat pumps. If one has a SEER of 13 and another has a SEER of 18, how much will I save by installing the more efficient one? – Jennifer F.

Dear Jennifer: Only a contractor can estimate the actual dollar savings for your home, but you can easily calculate the percentage savings. A more energy-efficient home uses less energy, so the dollar savings would be less. To calculate the percentage savings, divide the SEER of the least efficient model by the SEER of the most efficient one. Subtract this value from 1.0 to get the percentage savings. In your case, the savings would be about 28 percent.

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