Heated Flooring Options

Learn which heated flooring will keep you warm, and do it efficiently

By Kimbra Cutlip

Photo by iStockphoto.com

Heated floors provide cozy, even warmth throughout a room. They are more energy efficient than baseboard and forced-air systems, and when combined with solar, they are popular choices when greening a home or business. Heating with a radiant floor can save you up to 30 percent over heating with a forced-air system.

Heat Source: Hydronic (solar, gas or electric)

Hydronic floor systems circulate a heated fluid, such as water or glycol, through tubes in the floor. It is a very efficient way of heating space and is often used to heat an entire house or building. Older systems that used copper pipes have a reputation for being unreliable. New floors use specially treated polyethylene that will not corrode and comes in long rolls so it requires few fittings. You can use a standard gas or electric water heater to heat the fluid, but combined with solar hot water systems, these radiant floors offer a great opportunity for savings on energy costs.

Heat Source: Electric Coil

Electric radiant floors tend to be less efficient than hydronic floors and more expensive to run because of the cost of electricity. Used for smaller installations, such as a bathroom, sunroom or addition, they incorporate electric heat coils in a zigzag pattern through the flooring.

Heat Source: Hot Air

Air-heated radiant floors use solar energy to heat an air space that then radiates throughout the floor system. They are very inefficient for radiant floor use and not recommended. The best use for solar-heated air systems is in passive solar systems that take advantage of south-facing walls and windows, and use convection and sometimes fans to circulate heated air into the living space.

Installation Method: Poured Floor

Sometimes referred to as "wet" installations, poured concrete or gypsum floors involve embedding hydronic tubing or electric coils right into the floor. If you're converting an existing floor, you'll only use a thin layer of concrete or gypsum. New construction usually means pouring a concrete slab. In both cases, the floor stores the energy and creates a thermal mass. It is extremely efficient when heated with solar thermal systems. You have to consider floor strength and weight requirements for concrete. Also note that these types of floors take time to get up to temperature and to cool off, so they are not ideal for highly variable times when you may want heating at night and cooling during the day.

Installation Method: Subfloor Panels

Old-style systems involved sandwiching hydronic tubing or electric coils between two layers of subfloor with furring strips in between for support. In newer systems, panels or snap-in grids lie on top of subflooring and provide channels for the cable or tubing. Most systems incorporate aluminum fins or diffusers that spread the heat more evenly and improve efficiency. Because you don't have a thermal mass for heat storage as you do with concrete, subfloor systems are expensive to run on electric and better suited to hydronic. They are a good solution if you want to build radiant floors into an existing structure.

Installation Method: Under Floor

In this method, tubing or coils run beneath the floor between joists. They clip into aluminum strips on the underside of the floor. Usually you need to drill through the joists to install the tubing or cables. You will also need reflective insulation beneath the tubing to prevent heat loss. Because you are heating an air space, these systems need to run hotter than embedded floors.

Flooring: Ceramic or Slate Tile

Ceramic and slate tiles conduct heat well and provide thermal storage. When you lay them over a concrete floor, you retain the advantages of thermal mass. Installed over the other systems, they also provide some thermal storage and help improve the efficiency of the floor.

Flooring: Stained or Painted Concrete

If you are using a poured floor, you can leave the concrete bare and stain or paint it. Decorative concrete options are elegant enough that high-end hotels, restaurants and showrooms often use them.

Flooring: Wood, Carpet and Linoleum

Any floor covering that provides insulation, such as wood, carpet and linoleum, reduces the efficiency of radiant floor heating. If you intend to use an insulating covering, factor that information into the floor design. You may need to run the floor hotter than if you used tile or concrete. Consider throw rugs or area rugs instead of carpets.