Radiant Heating
The concept of heating dates all the way back to ancient Rome, where slaves tended fires that sent hot air through channels under elevated floors adorned by elegant marble. This option is rapidly becoming a popular nowadays in new home construction in the United States due to its cost-effective efficiency. There are three different radiant heating systems: hydronic, electric, and air-heated. Electric and hydronic radiant heating systems are more efficient and popular, than air-heated systems. Heat from a radiant system does not rise like heated air from a traditional heating unit; it spreads in all directions.
Electric
Electric radiant heating systems are the most versatile when it comes to installation. Rolled cables are attached in a looping pattern using braces to mats, mesh, or film constructed of resilient, heat-conductive materials. The mats can be embedded in the concrete slab during construction, installed under the subfloor, or even placed directly under the flooring. Electric systems are frequently the best choice for after-construction additions because of the versatility of installation.
Electric floor heating is controlled by independent zone thermostats which can be set to heat just the floor for barefoot comfort, to raise the temperature of a single room, or to heat an entire house. This method of heating is also gaining popularity as a method to de-ice driveways and sidewalks as an environmentally friendly alternative to chemicals or salt.
Hydronic
Hydronic radiant heating systems circulate with heated water through tubing embedded in the concrete slab. Due to the nature of the installation, this is usually done during construction. The advantage to a hydronic system is choice of power supply. The water can be heated with electric, solar, geothermal, natural gas, oil, wood-fired boilers, or any combination of these. They can also be installed with zone control using a series of pumps.
Problems with this type of heating in the past were due to inferior tubing, sometimes requiring that the floor be ripped up for repair. Today’s materials are stronger, more leak-resistant and the system is far less likely to require attention.
Air-Heated
Hot air heating is simply not very efficient in comparison with electric and hydronic. For this system, air is heated and pumped through a system of pipes embedded in the floor. This method warms the floor itself, but cannot be counted on to warm an entire house, requiring that a secondary method of heating must be employed.
Flooring options compatible with radiant heating
Before you consider types of flooring for your radiant heating system, check with a professional. If you’re installing a radiant heat in a new home, flooring choice should be carefully considered. After a hydronic heating system is installed, most experts agree that the heat should be turned on and run for at least 3-6 days before the flooring is installed to leach any moisture from the concrete. If the slab itself is less than 60 days old, extend the drying time to 30-60 days, especially if you are using any kind of wood or laminate flooring.
Porcelain, ceramic, and stone tile
Tile and stone are ideal to use with a radiant floor heating system. All are excellent heat conductors. They do not expand and contract with heat and are highly resistant to warping or cracking.
Carpet
Carpet is not a good conductor for heat but it is a good choice of floor covering a radiant heat system. This is a great pick for worming your toes but it will be a little more difficult to heat the entire room. The best carpeting option for radiant heat is a thin carpet with a low pile (for example Berber with a thick pad).
Laminates
Laminates should be used with caution. Careful consideration must be given to the installation to insure the underlying floor structure and concrete is dry in order to minimize changes dues to heat and moisture. Adhesives are also important to consider.
Vinyl
Vinyl has come a long way since the old linoleum floors of the sixties. Vinyl is not an ideal choice for heat conduction, but the good news is that vinyl flooring can be installed over radiant heat with a temperature limit set by the manufacturer. The down part is that poor quality vinyl flooring may discolor or emit a foul odor when heated.
Hardwood and Bamboo
Wood has a natural tendency to react to both temperature and moisture, so installation over radiant heating will be far more successful in a dry climate.
Wood is not a static material. It swells and contracts with changes in temperature and because of the moisture in the air. This can be problematic when it comes to floors, especially in areas of high humidity. Look for a kiln-dried wood that is quarter-sawn as opposed to plane-sawn. Quarter-sawn wood less likely to warp or crack since it has a tendency to expand in thickness and not width. Many experts recommend that you run the radiant heating for at least 72 hours before taking delivery of the wood flooring, then store the wood in the room where it will be installed with the radiant heating turned on to help the wood acclimatize to the moisture content in the air. Installing hardwood over a radiant floor heating system is tricky, but it can work out leaving warm and beautiful results. Always raise the heat gradually, allowing the wood to adjust. A down side is the fact that temperature changes can cause damage to the structure of the floor.
Engineered hardwood flooring is one wood flooring option generally more suited to use with radiant heat. Engineered hardwood flooring is made up of several layers of solid wood or fiberboard, much like plywood or particle board. The multiple layer construction makes engineered flooring and also much more dimensionally stable and less likely to expand or contract with changes in temperature. Most engineered flooring can be “floated” making it ideal for installation over concrete. The suitability of an engineered hardwood floor will depend on its construction, and the wood species and adhesives used in the manufacture process.
Always consult the manufacturer or retailer before making any changes.