Q. I want to replace my old discolored rusty floor registers with new decorative brass or wood ones. They must have good air flow adjusters because not all of our rooms stay cool enough. What types are best? — H.W.

A. It is not uncommon to have difficulty air-conditioning or heating all the rooms evenly. Installing new floor registers, with effective adjustable air louvers, will help to even out the room temperatures.

The most elegantly designed registers are made from solid brass, iron or aluminum castings. These are highly polished and finished with a tough epoxy or baked lacquer finish.

One solid metal register, by Reggio, uses a decorative inner circle section as the adjuster for the air control louvers. These high-quality solid metal registers weigh from three to 15 pounds and last a lifetime.

Natural wood registers are becoming increasingly popular in contemporary homes. These are often made of unfinished solid oak for custom staining. “Flush” styles fit level with a hardwood floor surface. These are slightly oversized to fit over a standard metal register with adjustable louvers.

For simple do-it-yourself installation, choose a “drop-on” design. These are available for carpeting or hard flooring. An extra wide self-rimming edge covers uneven openings that most do-it-yourselfers end up sawing.

For someone on a tight budget, new low-cost snap-in plastic registers are attractive and efficient. The plastic louver slide is designed to give precise control over the amount of air flowing out of the register.

Several plastic designs use thin scented or washable filters built into the register. This filter helps to catch any dirt that gets past the furnace filter. The filter can be cleaned without removing the entire register.

To balance the room temperatures, first try adjusting the louvers in your registers to regulate the amount of cool air going to each room. If this does help, try adjusting the dampers in the main branch ducts.

Installing an auxiliary fan in the duct leading to the warm room helps. There are many designs to fit any duct size or shape. They come on when the air conditioner blower starts. A fan-powered through-the-wall or floor register helps distribute the air more evenly throughout your home too.

A register fan is a simple do-it-yourself option. It mounts over a register and draws more cool air to the problem room. It has a built-in thermostat and automatic controls to operate in either a summer or winter mode.

Write for Update Bulletin 699 showing a buyer’s guide of 20 manufacturers of auxiliary duct, wall, floor and register fans and new decorative wood, solid brass and plastic adjustable registers, size ranges, colors and options. Please include $2 and a business-size SASE. Send to James Dulley, 6906 Royalgreen Drive, Cincinnati, Ohio 45244.

Q. I am planning to build a small solar heater for my backyard workshed next fall. I will use sheet metal for the collector. Whenever I drill a hole, it leaves a nasty burr. What can I do? — D.A.

A. I worked for many years as an engineer at a sheet metal fabricator and have run into every sheet metal problem. Try drilling the sheet metal with a drill press and with the sheet fixed down to the table or a piece of wood.

When using a hand drill, you most often get a burr. Don’t file it. The hole will get too big or you’ll scratch the galvanized surface. Put a slotted round head screw in the drill and use it as mini reamer to trim the burr.