QUESTION: How can I fix a lamp when the on-off knob has broken off? Also, is there a way to lighten a lampshade that has yellowed on the inside?ANSWER: If possible, take the knob from the lamp or the lamp itself to your local hardware store. You should be able to find a replacement knob. If not, contact a lamp repair shop. They're listed under "Lamp and Shade Repair" in Yellow Pages directories.As for the lampshade, there are two types: shades with fabric inside and out and shades that are fabric on the outside with a plastic or paper liner. Yellowing typically occurs in the latter type as heat from the bulb makes the liner more opaque. If cleaning the shade doesn't help, it's time to get a new shade. For the best transmission of light from your lamp, try a light-colored, all-fabric shade and, if possible, use an appropriate three-way bulb.

QUESTION: My parents have an electric water heater in their home and my dad insists that turning off the heater saves him money, so he only turns it on before it's needed for dishes or showers. Mom and I say the water heater should be left on all the time so it doesn't have to heat the entire tank of water when it heats.ANSWER: If it's an old water heater with no jacket or pipe insulation, your dad may be right, said Phil Smith, an energy specialist at the Minnesota Energy Information Center. However, if it's a high-efficiency electric unit, he said there isn't much to be gained.You could add a tempering tank to warm the water before it reaches the heater. Or, because you're heating with electricity, a solar water heater could be a great investment, said Smith. They are readily available, reliable and can cut your water heating bill in half, he added. Such a purchase also would qualify for a federal tax credit of 30 percent of the price.

Send your questions to Fix-it in care of the Star Tribune, 425 Portland Ave. S., Minneapolis, MN 55488, or call 612-673-9033, or e-mail fixitstartribune.com.