How to Properly Install Radiant Floors

Under floor radiant heat describes the generation of heat into flooring through a series of heating cables. Often used in bathrooms, radiant heat flooring can be installed without the aid of a flooring professional. The benefits of underfloor heating, also known as low-temperature systems, are numerous. The cost of installing radiant floors will vary according to the size of the space and the differences in radiant heating technology.

Radiant heating requires a lower heating temperature than typical convection heating systems.

There are two types of radiant heating: electric and hydronic. Electric radiant heating systems use electrical wiring to generate heat through mats or cables. Hydronic radiant heating systems use plastic tubing to pump heated water or glycol throughout the area and require attachment to a water heater or boiler and heat exchanger. Aluminum plating is often placed beneath hydronic systems to retain and spread heat in wood subfloor applications. These are known as dissipation plates and may decrease heat loss in hydronic systems. Hydronic heating may be more efficient for whole-house radiant heating compared to traditional radiators.

To install radiant floors, first determine if under floor heating will effectively heat the desired space; always consult a professional radiant heating specialist to properly size a radiant heating system.  The overall cost of the radiant heating system should be compared to a traditional forced air system.  Cost of a hydronic radiant heating system varies depending on surfaces to which the system is being installed, as well as overall demands on the water floor heating required.  To make sure that the electrical needs of the radiant floor are met, a dedicated 15 to 20 amp protected circuit is required. If a protected circuit is not already present, the services of a qualified electrician are recommended. Make sure to disconnect any electrical power sources prior to completing electrical work and working on your radiant heating system.

Radiant heating can be installed above or below subfloors. If installing under a subfloor, prepare the area by removing existing flooring. Always install insulation in conjunction with most radiant heating systems. This ensures that any heat generated by the radiant heating system is pushed to where it is most needed. Radiant heating may require raising the height of the floor, so make any floor height adjustments prior to laying the heating cables. Choose a radiant heating system that can be installed in the desired space. When laying heating cables, place them in ‘walking paths’ where they will be of most use. Electrical cables should not run anywhere where plumbing may need to be put through the floor and any other services may puncture and disrupt the electrical radiant floor. Once the electrical cables are placed on the floor, secure the cables with thinset mortar. Place a conductive flooring made of ceramic or vinyl over the cables and allow time for drying. Carpet or thick flooring is not recommended as it may trap heat and prevent it from rising to heat the air. Connect the radiant heating system to a thermostat and program the thermostat. Many new thermostats work in conjunction with outside temperature monitors, which help increase the reaction time of the radiant floor heating or warming system.