Q. We have a problem keeping several rooms comfortable. These rooms are either chilly during winter or hot during summer. What are some efficient methods to balance out the temperatures in our home?

A. There are many reasons why various rooms do not stay warm or cool enough. One common reason is the number and orientation of windows. South-facing windows can cause a room to overheat during summer. North-facing windows, especially old leaky ones, can make a room chilly during winter. This can be corrected by installing new windows or insulating shades.

The walls of the ducts may be losing or gaining heat as the air makes its way from the furnace or central air conditioner to the rooms. A simple method to check this is to hold a thermometer in the register outlet air in each room. If there is a significant difference in the temperature, wrap insulation around as much of the duct as you can reach.

Another reason for uneven temperatures is not enough heated or cooled air is getting to those problem rooms. Put your hand over room outlet registers to compare the flow rates. If a room is far from the indoor blower, the duct creates more air flow resistance. This problem is exacerbated by the fact that longer ducts also lose more heat through their walls.

Check the damper plates in the ducts near the furnace to be sure the ones leading to the problem rooms are not partially closed. Try partially closing the dampers leading to the other rooms. This may force more heated or cooled air to the problem rooms. The settings of the duct dampers for each room will likely have to be changed from summer to winter.

Also make sure the room register baffles are open fully opened. Installing a deflector over the register can help direct heated or cooled air out into the room. This is particularly true when air-conditioning because cool air tends to hang near the floor and not circulate throughout the room.

Installing a duct booster fan can help get more air flow to the problem rooms. Duct booster fans are designed to fit into the ducts (round or rectangular) near the furnace blower. Some sense when the blower starts and they come on automatically. Others have their own thermostat or can be connected to the main blower controls.

Register booster fans, which mount over the outlet register in a room, can also help. They are easier to install than a duct booster fan and provide more control over the room temperature. The register booster fan plugs into a standard wall electric outlet. It has its own thermostat so it comes on only when the main blower is running. The small fan motor uses only about 30 watts.

The following companies make booster fans:

••Aero-Flo Industries, (219) 393-3555

••Field Controls, (252) 522-3031

••Suncourt Manufacturing, (800) 999-3267

The following companies make register deflectors:

••American Metal Products, (800) 423-4270

••Deflecto Corporation, (800) 428-4328

Send questions to: James Dulley, Chicago Sun-Times, 6906 Royalgreen Dr., Cincinnati, OH 45244, or visit www.dulley.com.