Question: I was recently in a house with "warm feet" radiant floor heat, and it was extremely comfortable. Can I install this type of heating system in just several rooms of my house and is it efficient? - Tim J.

Answer: "Warm feet" radiant floor heat is the most comfortable system available. It is ideal in all climates for its comfort, good indoor air quality and low utility bills. You can use your existing duct system for central air-conditioning or install ductless central air.

Imagine getting out of your bed in the morning and putting your feet on a warm floor. The heat radiates up from the floor producing the same feeling as sitting in the sun by a window on a winter day. The heat will come up right through your existing carpeting.

Unlike forced-air or radiator systems where the warmest air stagnates at the ceiling, the warmest temperature is much lower with a radiant floor system. These systems are noiseless with minimal temperature variations. With no registers, you have total freedom in furniture placement and interior design.

A typical radiant floor system uses your standard water heater or a boiler for the heat source. Thin flexible water tubing is attached under the floor between the joists or in a concrete slab (new construction).

There are many types of tubing used by various manufacturers. The most commonly used is PEX (cross-linked polyethylene) and some manufacturers offer a lifetime warranty. The actual life is projected to be more than 100 years, so there is little chance of leaks.

A radiant floor system is easy to install in just one room or in your entire house. It can be a fairly simple do-it-yourself job. Many of the manufacturers offer installation kits (Vari-Takk or Radiant-Trak) to provide the proper tubing spacing and attachment under the floor.

For a second-story room, place the tubing on the floor and spread a thin layer of special cement over it or add another false floor. You'll just have to trim the door a little. This also helps block noise through the floor.

The key efficiency feature of a radiant floor is its unusual comfort. This allows you to save by setting the thermostat lower without feeling chilly. Also, room air is not excessively dried out as with forced-air systems.

Efficient zoning is simple with a radiant floor system. A central command unit controls the warm water flow to each of the room floors. You can literally set each room to a different temperature so your kids won't have to fight anymore over the thermostat setting.

Write for (or instant download - www.dulley.com) Update Bulletin No. 652 - list of 13 radiant floor system manufacturers, tubing types, comfort and design features and typical installation methods. Please include $3 and a business-size self-addressed envelope: James Dulley, Deseret News, 6906 Royalgreen Drive, Cincinnati, OH 45244.

Question: We have a wood-burning fireplace that we seldom use because it does not draw well and the room smells smoky. The chimney has a smoke shelf. Does that help or just impede the smoke path? - Patty T.

Answer: The purpose of a smoke shelf is to improve the draft of the fireplace so that your room does not get smoky. Basically, cool outdoor air flows down the chimney, hits the smoke shelf, mixes with the warm smoky air and flows back up and out. This draws out the smoke.

Make sure there is adequate combustion air for the fireplace by opening a window slightly. Also, the draft will be stronger on very cold days.