Underfloor Heating Systems

radiant floor heating
  • 10-100 hours
  • Advanced
  • 2,000-30,000

A variety of underfloor heating systems have been in use for some time and are available nowadays when you are looking to retrofit your current heating setup. There are two basic ways to provide heat in an underfloor system, with two subtypes for each. The basic methods of heating are electric and hydronic, meaning hot water.

The subcategories for the electric method are electric cable heat and electrical matting, while the different types of hydronic systems are wet and dry installations. All types of underfloor heating are known as radiant heating. Rather than blow hot air through a system of ducts and out of vents, radiant heat radiates out of a surface. For this reason, it is a much more efficient means of central heating.

Electrical Underfloor Heating

radiant heating under wood flooring

There are two main ways to run electrically powered heat underneath the flooring of your home—electrical cables that run through the living space, or the placement of electrical mats, which are laid out underneath floor material. The first method requires a good amount of electrical wiring skill. A lot of current is necessary to power an electrical cable heating system. In many cases a certified electrician is needed to install such a system in order to prevent overloading the individual circuits.

Electrical mats are easier for the do-it-yourselfer. Underfloor electrical mats are rolled out and covered by a flooring material, whether it is ceramic tile, granite or some other material. Of the two, electrical heating mats are easier to install but may not work with every type of flooring.

Hydronic Underfloor Heating

The second general method for underfloor heating is hydronic radiant heat. It is known as ‘hydronic’ because it uses heated water to transfer heat to individual rooms. Hydronic heat requires some type of water boiler or water heater to heat the water at a central location and then pump it through the system of underfloor tubes to various rooms. The two basic types of radiant hydronic floor heating are called wet and dry installations.

Wet Installations

spreading a thin layer of material over radiant flooring

Wet installations are those that run the tubes through a layer of poured concrete. Tubes for hydronic heating must have an interior diameter of at least ½ inch in order to be effective. Tubing of this size cannot simply be covered like electrical cable, hence the need to set it into concrete.

Wet installations have the doubly beneficial effect of using the concrete slab as a thermal heater. In other words, the concrete stores the heat that is pumped through by the water, making it very efficient.

Dry Installations

The other type of underfloor hydronic system is known as a dry installation. Instead of being set in a concrete slab, a dry installation runs between plywood boards. It can be found on top of the subfloor of a home or building. It requires tubing of the same size, but because there is no concrete slab, it is a little less involved to install after the home is built. In many cases the tubing in a dry installation is set into a liquid substance that hardens. This hardened compound acts like a thermal mass much like concrete.

You can heat your home using underfloor heating methods that either consist of radiant heat-producing electrical cables, mats, or a hydronic system. The hydronic variety uses heated water to transfer heat into the rooms. Instead of relying on the inefficiency of force heated air, underfloor heating systems conduct and transfer heat in a much more effective manner.