TempZone Flex Roll Kits with nJoy WiFi Thermostat Frequently Asked Questions
Frequently Asked Questions
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Yes — the nJoy WiFi (UWG5-4999) thermostat supports all three major smart home platforms:
- Amazon Alexa — use voice commands to set temperature or turn the system on and off.
- Google Home / Google Assistant — integrates with Google Home routines and Nest displays.
- Apple HomeKit — manage your floor heating from the Apple Home app and Siri.
The nJoy also works with the dedicated nJoy app (iOS and Android), which gives you full remote control including scheduling, temperature adjustments, and energy usage history from anywhere.
The nHance (UDG4-4999) and nTrust (UTN5-4999) thermostats are not WiFi-enabled and do not integrate with smart home platforms. They must be controlled locally at the wall unit.
WarmlyYours offers three current thermostat lines for electric floor heating, each suited to different budgets and feature needs:
- nJoy WiFi (UWG5-4999) — The flagship smart thermostat. Connects to your home WiFi and is controlled via the nJoy app (iOS / Android), Amazon Alexa, Google Home, and Apple HomeKit. Features a full-colour touchscreen, 7-day programmable schedule, floor and air sensor support, and built-in GFCI protection. Best for homeowners who want remote access and smart home integration.
- nHance (UDG4-4999) — A premium non-WiFi programmable thermostat with a large colour touchscreen. Supports a 7-day schedule, floor and air sensor, and GFCI protection. Best for those who want a high-quality display and programmable scheduling without a WiFi requirement.
- nTrust (UTN5-4999) — A straightforward non-programmable thermostat for simple manual control. Compact form factor, supports a floor sensor, and includes GFCI protection. Best for secondary rooms, rental units, or anyone who prefers simple set-and-forget control.
All three thermostats are compatible with every WarmlyYours electric floor heating system (TempZone, Environ, and Slab Heat products). If you need help choosing, our radiant experts can recommend the right model for your project at no charge.
The early start (also called adaptive start) feature allows a programmable floor heating thermostat to automatically begin heating before your scheduled "comfort on" time, so the floor reaches your desired temperature precisely when you need it — not after a warm-up delay.
For example, if you schedule your floor to be warm at 7:00 AM and the system typically takes 45 minutes to reach temperature, the thermostat with early start will automatically begin heating at 6:15 AM.
Over time, the thermostat learns the thermal characteristics of your floor (the flooring material, the thickness of the installation, and the starting temperature) and continuously refines the lead time for increasingly accurate scheduling.
The nJoy WiFi (UWG5-4999) and nHance (UDG4-4999) thermostats support early start as part of their 7-day programmable schedule. The nTrust (UTN5-4999) is a non-programmable thermostat and does not have this feature.
While WarmlyYours electric radiant floor heating systems are typically installed by your floor covering contractor, a licensed electrician is recommended for the final thermostat hook-up. With every quote, we provide an Installation Plan layout, together with an electrical plan that has all the info required for the electrician.
Our electric radiant floor heating systems have withstood rigorous safety testing and earned the UL listing. They produce much less EMF than common household appliances like your TV or vacuum cleaner. The EPRI (Electric Power Research Institute) tests all electrical devices and publishes the data. Many common household appliances are tested at a distance of 6 inches. The test results indicate that on average, the EMF emitted for the following appliances, measured in Milligauss (mG) units, is:
Vacuum Cleaner: 300 mG
Microwave: 200 mG
Portable Heater: 100 mG
Dishwasher: 20 mG
Washing Machine: 20 mG
WarmlyYours TempZone™ (Twin): 1.8 mG
The floor heating systems are offered in both 120 volt and 240 volt for the North American market. A 208 volt breaker panel can also accommodate our 240 volt floor heating system. It is important to note that the energy consumption will be the same: a 240 volt system will not cost more to operate than a 120 volt system. You are billed in kilowatts, and the 120 volt and 240 volt systems use the same amount of kilowatts. WarmlyYours often specifies a 120 volt system in smaller projects while a 240 volt system is typically recommended for larger projects (120 square feet of electric floor heating coverage or more). The benefit of switching to a 240 volt system is the reduction in amperage. Our programmable thermostat can control a radiant floor system up to 15 amps. The 120 volt system will reach 15 amps at 120 square feet of electric floor heating coverage. However, the 240 volt system will reach 15 amps at 240 square feet of electric floor heating coverage, allowing a much larger system to be connected to the thermostat. For installations over 240 square feet, a relay contactor or power modules are needed.
Please keep in mind that you must check your electric floor heating system with a digital ohmmeter in conjunction with a Circuit Check™. Take an initial reading as soon as you take the product out of the box to verify that it is within -5% / +10% of the values stated on the product’s label. This will give you a basis of comparison for future readings. Take a second reading once you have positioned the system to match your custom installation plan. It is also advisable to take an additional reading in the middle of the tile installation, just to make sure that the Circuit Check™ is doing its job. Then, take a final reading when you are finished with the floor installation and are ready to hook up the thermostat.
The Circuit Check™ is a tool developed by WarmlyYours to give you peace of mind and ensure trouble-free installations. Simply hook up the cold leads to the tool while you position the system to match your custom installation plan.
The Circuit Check™ will continuously monitor the continuity of the circuit during the installation of your system and during the installation of your flooring. The Circuit Check™ beeps immediately when a short in the system is detected, alerting you to a potentially damaged cable in the area you are working, before you lay the tile over the electric floor heating system. The WarmlyYours technical support team is available 24/7 to provide assistance if the alarm sounds, or if you would have any questions during your installation.
When installing electric floor heating over a concrete slab, an insulating underlayment like ThermalSheet is highly recommended to ensure efficient operation, faster heating times and warmer floor temperatures.
When WarmlyYours electric floor heating systems are being installed on a concrete slab, we strongly recommend adding a layer of insulation over the slab prior to installing the system. While our electric floor heating provides up to 25% more heating power per square foot than many of our competitors, the slab will always act as a "heat sink." Some of the heat that would otherwise be transferred to the flooring surface will remain in the slab, causing the floor’s surface temperature to be considerably lower. This is true with any electric radiant floor heating system.
When installed on top of a concrete slab without insulation, it is generally accepted that electric floor heating will take the chill away from the floor and provide a small amount of warmth. Adding insulation on top of the slab and beneath any electric radiant floor heating system will allow a greater percentage of the heat generated to transfer to the flooring surface. This results in greater efficiency and therefore faster warm up times, higher expected surface temperatures and lower energy usage. The floor will have the capacity to warm to a comfortable temperature, and in some cases can be employed as the primary heat source for that room.
The recommended types of insulation are natural cork, insulated tile backer boards and insulated underlayment, such as ThermalSheet™ synthetic cork.
Yes. While there are some floor heating systems that can be installed beneath floor joists, most electric radiant floor heating systems will need to be installed beneath the floor itself. This is why the best time to install electric floor heating is during a remodel or as a part of a new construction, when a floor is being installed anyways.
If you’re interested in alternative radiant heating methods, check out our Infrared Heating Panels, which are wall-mounted and use infrared technology to provide supplemental heating.
Supplemental heat can be addressed by changing the spacing on cable installs. Floor location in the house is very important when considering adding supplemental heating to a floor. For example: If heating a second story floor, over a heated space, cable at 4" spacing can be used. The same type of heating over an unheated space would probably be done with TempZone Flex Rolls or TempZone Cable at 3" spacing. All heating is considered supplemental unless a heat loss calculation is done.
The breaker and wire sizes are selected based on the total amperage of the WarmlyYours heating system connected to a single thermostat. This information is on the WarmlyYours heating system's installation plan, electrical plan, or UL label. Based on guidelines from the National Electrical Code: loads up to 16 Amps may utilize 12 gauge wire with a 20-Amp breaker, and loads up to 12 Amps - 14 gauge wire with a 15-Amp breaker. Local code and/or other factors may change these guidelines.
Yes. The WarmlyYours TempZone™ floor heating system has withstood rigorous safety testing by the Underwriter's Laboratory and has received UL listing for the U.S. as well cUL certification for Canada. WarmlyYours offers thermostats that carry the CSA Mark and the UL listing, which certifies that the product has been tested under extreme conditions and meets applicable standards for safety and/or performance in the U.S. and Canada. All WarmlyYours thermostats contain a Ground Fault Circuit Interrupter (GFCI) which provides fail-safe protection against an electrical shock.
WarmlyYours’ 25-Year No Nonsense™ Warranty is the most comprehensive warranty in the industry. In the event of a defect, we cover not only the repair or replacement of the TempZone™ system, but ALSO any labor costs AND flooring materials required to perform the repair. We do not cover the cost of flooring that needs to be replaced in the event of a repair necessitated due to damage. If a product is damaged by a power surge, that would not be covered by our warranty
One thermostat can control multiple heating mats/cables as long as all the heating elements are using less than 15 amps:
TempZone™ will cover aprx. 120 sq. ft. for 120V systems and 240 sq. ft. for 240V systems on one thermostat.
Environ™ will cover aprx. 150 sq. ft. for 120V systems and 300 sq. ft. for 240V systems on one thermostat.
Slab Heat will cover aprx. 90 sq. ft. for 120V systems and 180 sq. ft. for 240V systems on one thermostat.
No. Never cut the heating cable. The floor heating cable is designed with a very specific resistance in order to consistently maintain heating at the chosen wattage per square foot. Trimming the heating cable would lower the resistance of the cable causing the system to overheat. Adding heating cable to the system would raise the resistance and the system would not heat properly.
The TempZone™ twin conductor cable present in our TempZone™ products is comprised of a double-insulated, coaxial heating cable. The total thickness of the system can be between ⅛” and 5/32” thick and will not noticeably affect the height of your installed flooring. The heating system is encased in 3/8" of modified thinset or Self leveling underlayment. You simply use that 3/8" layer throughout the space, eliminating any need for fillers.
Make sure any cracks or raised edges are sanded down before installation. Seal and patch cracks where possible. If needed, pour a layer of self-leveling cement to make sure surface is level and flat. Then proceed with instructions to install desired floor heating system and flooring.
It is strongly recommended that an insulating underlayment be installed between the slab and heating element to prevent heat loss.
TempZone™ is an electric floor heating system that operates like an electric blanket for your floors. TempZone™ is covered in thin-set or Self-Leveling Underlayment, and is installed over the top of your subfloor and beneath your flooring. The system provides a warm, even temperature across your floor, generating floor-to-ceiling radiant warmth to transform these naturally cold surfaces into warm floors. Ideal for kitchens, bathrooms or any room in your home where you would enjoy radiant warmth and comfort, the TempZone™ floor heating system is easy to install, operate and maintain.
No. Never cut the heating mat. The floor heating mat is designed with a very specific resistance in order to consistently maintain heating at the chosen wattage per square foot. Trimming the heating cable in the mat would lower the resistance of the cable causing the system to overheat. Adding heating cable to the system would raise the resistance and the system would not heat properly.
If you think you have the wrong heating element, contact our 24/7 Technical Support Team by calling 1-800-875-5285.
The TempZone™ twin conductor cable present in our TempZone™ products is comprised of a double-insulated, coaxial heating cable. The total thickness of the system can be between ⅛” and 5/32” thick and will not noticeably affect the height of your installed flooring.
An electric underfloor heating system doesn't need to be left on all the time. The system can be completely turned off or set back to a lower temperature when not in use. If you have a programmable floor heating thermostat, then the system can also be set to operate only during specific times.
Yes, you can add radiant heating to an existing slab using "over-the-slab" systems like TempZone™ Flex Rolls or Easy Mats. These low-profile electric systems are installed on top of the existing concrete using thinset or self-leveling underlayment, allowing you to add warmth without tearing out the original floor.
Yes, we offer several options to help make your floor heating system water resistant or waterproof. Our TempZone product line is designed for wet areas - making it completely safe for rooms that will have water on the floor at times or may experience leaks or flooding. We also offer waterproofing bands for our TempZone Cable + Prodeso Uncoupling Membrane system. Allowing you to waterproof all seams and the perimeters of the wall - guaranteeing that your floor heating system stays safe and prevents water from leaking to areas below.
Never cut, shorten or splice the heating cable itself; cutting it damages the system. Only the non-heating cold lead can be shortened, as your product’s manual allows. Order the size your SmartPlan™ specifies, because unused cable can’t be cut off.
Some mats let you cut the mesh, never the cable, to turn or reposition them: TempZone™ and Environ™ Flex Rolls and Slab Heat mats. TempZone™ Easy Mats and Custom Mats are made to size and must not be shortened or cut. TempZone™ Cable has no mesh: lay all of it at the spacing on your SmartPlan™.
It depends on the floor. Tile and other bonded floors shouldn’t go over a loose plastic sheet: bond ThermalSheet to a cured, dry slab with modified thinset; a waterproof concrete sealer may be needed if slab moisture is above 10%. Under floating laminate or engineered wood, a plastic vapor barrier beneath the underlayment is fine. Fix any water seepage first.
Yes. Without insulation, a concrete slab draws heat down from the floor heating, so the floor warms slowly and uses more energy. Over an existing slab, lay ThermalSheet, WarmlyYours’ insulating underlayment, under the heating system to send the heat up into the floor. ThermalSheet replaces CeraZorb, which is no longer sold.
It depends on your flooring type and heating system. For electric radiant floor heating, underlayment is often beneficial but not always required.When underlayment is recommended:
- Floating floors (laminate, engineered hardwood, LVP): Use ThermalSheet, WarmlyYours' insulating underlayment, to direct heat upward and improve efficiency.
- Cold subfloors (concrete, basements): Insulating underlayment prevents heat loss downward.
When underlayment is not needed:
- Tile and stone installations: Heating cables/mats are embedded directly in thinset or self-leveling compound—no underlayment required.
- Glue-down LVP over concrete: System can be installed in self-leveling compound without additional underlayment.
Important note: WarmlyYours currently offers ThermalSheet as our recommended underlayment solution. While CeraZorb and cork underlayment were previously available and may still be found in older installations, ThermalSheet is now our preferred product for optimal performance and compatibility.Our free SmartPlan service includes underlayment recommendations tailored to your specific flooring and subfloor. With over 600,000 custom floor plans created, we ensure you get the right system configuration.
In most cases, yes — a dedicated circuit is strongly recommended and often required by local electrical codes. Here is why:
- Electric floor heating draws a continuous load (typically 80% of the circuit's rated amperage for NEC compliance). Adding other devices to the same circuit risks overloading it.
- Most WarmlyYours thermostats are rated for 15A at 120V or 15A at 240V. A dedicated 15A or 20A circuit — matched to the system voltage — provides safe headroom.
- GFCI protection is required by the NEC for all electric floor heating systems. WarmlyYours thermostats include built-in Class A GFCI, so an external GFCI outlet or breaker is not needed when using these models.
Always consult a licensed electrician and verify your local code requirements before installation. Our free design service includes circuit and load calculations for your specific system.
One watt equals about 3.412 BTU per hour. TempZone™ Flex Rolls, Easy Mats and Shower Mats, and TempZone™ Cable at 3-inch spacing, deliver 15 watts per square foot: about 51 BTU per hour for every square foot of heated floor. Environ™ delivers 12 watts per square foot, about 41 BTU per hour. For any product, multiply the wattage on its label by 3.412.
Only heated floor counts, and heating can’t run under cabinets or fixtures: 100 square feet of 15-watt heating produces about 5,100 BTU per hour. Compare that with your room’s heat loss.
TempZone™ Flex Rolls, Easy Mats and Shower Mats deliver 15 watts per square foot, and Custom Mats 12 to 15. TempZone™ Cable and Ruler Cable deliver 3.7 watts per linear foot, so their output depends on spacing: about 15 watts per square foot at 3 inches, 11 at 4 and 9 at 5. See TempZone Cable spacing and attachment.
Operating costs for electric floor heating depend on the heated area, system wattage, your local electricity rate, and how long the system runs: (area × watts per sq. ft. ÷ 1,000) × electricity rate × hours energized.
For example, heating a 35 sq. ft. bathroom with a 15-watt-per-square-foot system draws 525 watts (35 × 15 ÷ 1,000 = 0.525 kW). Running the system for 8 hours a day costs approximately $0.68/day ($20.49/month).
You can calculate specific operating costs for your project using our
Operating Cost Calculator for Floor Heating
Estimate your daily and monthly energy costs based on room size and local rates.For the same wattage and operating time, 120V and 240V electric floor heating use the same amount of energy and produce the same heat. A 240V system draws less current for the same wattage, which can accommodate a larger heated area on a suitable circuit. Choose the heating product and control voltage to match the supply, and have an electrician verify circuit capacity, wiring, and applicable code.
Use a floor sensor (included with most WarmlyYours kits) to prevent overheating, especially with temperature-sensitive floors like hardwood, laminate, and LVT. If using the nJoy WiFi or nHance thermostat, you can use the built-in air sensor or a combination of floor and air sensors. The nTrust thermostat only supports a floor sensor. Always use a floor sensor with hardwood, laminate, or LVT to respect the floor's maximum temperature limit (usually 80–85°F / 27–29°C).
In TempZone™ Flex Rolls, Easy Mats and Shower Mats, the heating cable is fixed 3 inches apart. Custom Mats follow each design. TempZone™ Cable and Ruler Cable are spaced as you install them: 3, 4 or 5 inches on GripStrips™, or set by the membrane, and never closer than 3 inches. See TempZone Cable spacing and attachment.
The amount of amperage draw depends upon how large the area is that you are heating. For coverage of areas less than 30 square feet, a 120V TempZone system will draw less than 4 amps. If you have a larger area over 240 square feet of heated space, then you will need a larger breaker plus additional controls. No matter what the size of the area you choose to heat, we recommend a dedicated circuit for your electric radiant floor heating system.
WarmlyYours floor heating systems are backed by our industry-leading warranties, among the longest in the radiant heating industry:
Product Warranties:
- TempZone™ systems – 25-year product warranty on heating cables and mats
- Environ™ systems – 25-year product warranty on heating cables and mats
- Thermostats – 3-year manufacturer warranty on all models
- Installation materials – Covered under respective product warranties
What's Covered:
- Manufacturing defects in heating cables, mats, and components
- Free replacement of defective products during warranty period
- Technical support for troubleshooting and diagnostics
- Installation guidance to prevent issues before they occur
Why Our Warranty Matters:
- Proven reliability – Over 25 years of manufacturing experience
- Rigorous testing – Every system tested before shipping
- Quality materials – Premium components designed for decades of service
- Installation support – 24/7 tech support during installation to prevent warranty issues
- Peace of mind – Your investment is protected for decades
Warranty Registration:
Your SmartPlan™ includes warranty documentation and testing logs. We recommend:
- Testing resistance before, during, and after installation
- Documenting all resistance readings
- Taking photos of your installation
- Registering your system online after installation
Beyond the Warranty:
Even after your warranty period, our support team remains available to help with:
- Troubleshooting and diagnostics
- System expansions to additional rooms
- Replacement thermostats and accessories
- Technical guidance for any issues
Your SmartPlan™ ensures your system is properly designed and installed from day one, minimizing the chance of issues and maximizing the life of your investment.
Keep the power lead factory splice and the cable end seal outside the shower area and at least 1 ft. away from shower openings or other spots normally exposed to water. The control must be located at least 4 ft. from shower openings, where it cannot be exposed to water or touched by someone in the shower.
More output lets the floor make up more of a room’s heat loss. TempZone™ Flex Rolls, Easy Mats and Shower Mats, and TempZone™ Cable at 3-inch spacing, deliver 15 watts per square foot: up to 25% more heating power than the nearest competitor’s systems, and enough for primary or supplemental heat. Cable at 4-inch spacing, about 11 watts per square foot, is for supplemental heat only.
Whether floor heating can be a room’s only heat source depends on that room’s heat loss. An uninsulated concrete slab, for example, absorbs part of the heat, so insulating over it helps. WarmlyYours can calculate your room’s heat loss before you decide.
A floor sensor measures floor temperature so a compatible thermostat can regulate comfort and enforce the flooring manufacturer’s temperature limit. Some thermostats, including nTrust 2.0, offer a regulator mode without a sensor, but that mode does not measure floor temperature. Use sensor-based temperature control whenever required by the flooring or heating-system instructions.