Solar Lights Need No Wiring and Energy’s Free

QUESTION: I want to add outdoor lighting around my house, but I am not very familiar with electrical wiring. Do those solar-powered lights really give off much light and how should I select them?

ANSWER: Solar-powered yard lights are extremely effective, and they are ideal for the do-it-yourselfer. You just stick them in the ground or mount them on a wall (no wiring), and let the sun do the rest. It takes about five minutes to install one. With no wiring, you can move it at any time.

Since they use no electricity, they produce no pollution and do not harm the environment. And they operate for free. The rechargeable battery pack should last several years before being changed.

Most lights are designed with solar cells inconspicuously built into the top so they face the sun. These charge a battery pack inside of the light housing. An electric eye automatically turns the lights on after dark.

The amount of light given off ranges from low-intensity walk marker and landscape highlight units to as much as a 60-watt light bulb from high- intensity units. On the high-intensity units, there’s a 14-foot wire between these bright lights and the solar panel. You can easily mount the light in a work shed or other area and mount the solar panel on the roof.

This high-intensity light also has a timer that keeps the light on for about 20 seconds after it’s switched off. This gives you time to leave the room or area while it’s still lighted.

Another application is a security motion-sensing solar-powered light. When it senses motion, a bright light comes on and stays on until it senses no motion for about 2 minutes. It lights up to 120 times on one solar charge.

You can also get solar-powered house number lights. You can mount these on your mailbox or your house. The numbers automatically light at night and are visible in the day as the batteries charge.

There are some significant differences among the various solar-powered lights available. Select one that has a vented battery area and a high- temperature battery. Common rechargeable batteries become less effective when they get too warm from the sun.

Double-protected solar cells and circuitry are best. Since these are exposed to sun, wind, rain and dirt 24 hours a day for years, they must be durable. The most efficient type of solar cells are the crystalline type. They produce about twice as much electricity as the thin-film cells.

You can write to me for Utility Bills Update No. 269 listing manufacturers of solar-powered lights, the types of lights each offers, types of solar cells and batteries used, and whether they are vented and double protected. Please include $1 and a self-addressed business-sized envelope. Send your requests to James Dulley, c/o Los Angeles Times, 6906 Royalgreen Drive, Cincinnati, Ohio 45244.

Should Bathroom Vent Need Flapper?

Q: I looked up in my attic the other day and noticed that the duct from my bathroom vent fan stopped directly under my roof. There is no vent flapper over it. Should I install one?

A: There probably is a lot of outdoor air leaking into and out of your house when the bathroom vent fan isn’t running. First, you should shorten the duct so it does not stop directly under the roof. That dumps much potentially-damaging moisture on the sheathing, especially in the winter.

It probably would help to add a lightweight plastic dryer vent flapper over the duct. Check with the manufacturer of the vent fan first to determine if the fan has enough power to blow open the vent flapper.

Speeding Blower Could Affect Air Comfort

Q: I plan to adjust the blower motor pulley to increase its speed for high air-conditioner efficiency. Will this affect the comfort level too?

A: Speeding up the blower can improve the efficiency of your central air conditioner. By moving more air across the evaporator coils, the heat transfer rate is greater. Check with your air-conditioning contractor about the recommended speeds.

While a faster blower speed improves heat transfer, it may reduce the amount of dehumidification. The air does not get cold enough to condense as much water vapor out of it. Depending on your climate, you may get a cool clammy feeling.