HeatTechProducts.com offers (3) basic models of floor sensing thermostats by Honeywell/Aube:
Standard 120V or 240V, 7-day programmable thermostat – TH115-AF-120S or TH115-AF-240S
Dual voltage 120/240V, 7-day programmable thermostat with 5 mA GFCI – TH115-AF-GA
Dual voltage 120/240V, non-programmable thermostat with 5 mA GFCI – TH114-AF-GA
Selecting the proper thermostat model will allow to maximize the efficiency of the electric in floor heating system, achieve desired comfort levels in individual areas of the house and minimize monthly operating costs.
All (3) thermostat models come with a floor sensor (Honeywell model AC112-01) which has 15ft long leads. Floor sensor is commonly installed in between the heating cables at the same time when the in floor heating system is installed. The sensor is then connected to the thermostat and allows it to accurately read the floor temperature.
The reason floor sensing ability is important, is due to timely temperature readings which allow the thermostat to turn the system on or off when temperatures reach threshold levels. Ambient temperature reading feature is also present on all (3) thermostat models, but is considered much less effective, since it presents a slower response time for the system.
A standard programmable floor sensing thermostat (TH115-AF-120S or 240S) is the most popular choice among customers who use HeatTech electric in-floor heating system. A programmable thermostat is designed to allow user to pre-set desired temperatures throughout each day of the week using (4) time settings per day. The main advantage of such thermostats is the ability to optimize the use of the electric in-floor heating system to improve energy savings and reduce associated operating costs.
A non-programmable thermostat is a simplified version which does not offer programming features and instead allows user to change temperature settings on demand.
The main difference between a regular (TH115-AF-120S) and a GFCI thermostat (TH115-AF-GA or TH114-AF-GA) is a 5mA (0.005 Amp) built-in Ground Fault Circuit Interrupter (abbreviated GFCI). Having a floor sensing thermostat with GFCI feature is similar to having an additional high-sensitivity circuit breaker in the system. This feature adds extra safety by detecting the slightest current leakage (change in current draw by the system) and shutting down the power to prevent electrical shock.
GFCI thermostats are mainly recommended for areas where high moisture levels may be present (such as showers, steam rooms) and should the electrical cable ever be damaged – whether during of after the installation, will safely shut down the system until necessary repairs are made.
Since HeatTech in floor heating system requires a class “A” GFCI circuit breaker regardless of the application and installation type, GFCI thermostats are installed only when circuit breaker lacks the GFCI feature. Therefore, a standard programmable or non-programmable thermostat is a more popular choice.