Changing a light fixture in your ceiling is one of the easiest home improvements you can undertake. However, there can be problems if you choose one that's too heavy. Last night we attended "The Phantom of the Opera." At one point, a chandelier the size of a car was thrust across the room as a special effect. This was a reminder that most modern electric ceiling boxes are not made to carry very much weight. Before you invest great sums of money in a light fixture, find out how much it weighs. Ten or 12 pounds will be OK. A metal electric box attached directly to a solid framing member will hold about 25 pounds. Heavier fixtures require special attachments which can be time-consuming and expensive to install. With light fixtures, lighter is better. And that's the On The House tip for today.