SunTouch Floor Warming Products Frequently Asked Questions

General SunTouch and Floor Warming FAQ's


1.What makes the floor warm?

The blue heating elements in the orange weave of a SunTouch mat get warm and transfer heat to the floor. The floor, in turn, transfers heat to the rest of the room. WarmWire does this with stainless steel covered heating elements attached to straps. SunTouch UnderFloor does this with a warm blue aluminum surface suspended between floor joists.

2.Where do most people put their SunTouch floors?

Bathrooms are the most common place, followed by kitchens and entryways. Mudrooms are a great place for a warm floor. WarmWire works great in larger areas, like basements or great rooms.


3.Does SunTouch mat weaken or strengthen my floor?


SunTouch mats have been tested by the Tile Council of North America (TCNA) to ASTM C 627, officially known as "A Standard Test Method for Evaluating Ceramic Floor Tile Installation Systems Using the Robinson-Type Floor Tester. It tests for deflection under loads, such as mortar for Portland cement installations, concrete for thin-bed installations, and plywood with a composition board or other sheeting material. SunTouch mats passed these tests for HEAVY classifications, such as shopping malls, commercial areas and etc. SunTouch mats apparently add tensile strength to the tile and mortar sandwich. When in doubt, follow TCNA and ANSI (American National Standards Institute) specifications.


4.Is SunTouch electric floor warming efficient?

Radiant floors warm people and objects directly without overheating the air. Electric radiant converts nearly all its energy into a usable form. Set the home thermostat lower and still be comfortable. Use a programmable SunStat and the system automatically sets back to a lower temperature when the rooms are not in use. Insulate below the floor or below the heating system and on top of the concrete slab to allow the system to respond faster and use less energy.


5.My bathroom is heated, so do I need floor warming?


Even when bathrooms are heated with forced air or baseboard, the tile floors are cold. Imagine starting the day by stepping out of the shower and onto a warm, comfortable tile floor!


6.Is there any advantage to a "low voltage" electric radiant heating system?


No. SunTouch and competitors deliver about the same amount of energy to the floor. They may use fewer volts, but require higher amperage to be able to generate the same wattage (heat delivery). SunTouch, however, uses line voltage, and lower amperage to deliver the necessary wattage. This allows a larger SunTouch system to be installed with a smaller breaker. Low voltage systems use transformers that are noisy, hot and hard to hide, both visually and acoustically. All North American bathrooms have access to 120 Volt (VAC) power and by code, must install SunTouch systems with GFCI protection. A GFCI detects ground faults and will disconnect the energy to the heating system within milliseconds if necssary. Low voltage systems are not necessarily low EMF systems. Before buying any product, ask for the policy on Electromagnetic Field (EMF) shielding.


7.What does it mean that SunTouch is a very low EMF product?


SunTouch twists two heating elements together to minimize EMF. We test our products to a protocol known as REET (Radiant Electric Emissions Test) which is conducted by an independent third party test lab known as ETL/Semko. Scientists don't know exactly what EMF does to a human body, but recommendations suggest to reduce EMF exposure.


8.What voltage do I need for my SunTouch floor?


SunTouch is built for 120 VAC or 240 VAC for warming larger areas.



9.Does 120 VAC work better than 240 VAC?



Both systems have the same efficiency. The best option is to see what power is available for your installation. 240 VAC is more common outside the United States and in commercial applications. A SunStat can control up to 150 square feet of heated floor on 120 VAC or 300 square feet on 240 VAC.





10.What's the warranty on SunTouch products?



SunTouch heating elements are covered by a limited twenty-five (25) year product replacement warranty. SunStat controls have a two year limited warranty. The SunTouch warranty is transferable to a new homeowner, unlike most other radiant companies. SunTouch warranties the product, not just the original homeowner.



11.What makes your heating elements special?



Heating elements must resist jobsite abuse and long term aging. SunTouch uses an expensive wire insulation called ETFE (Ethylene tetrafluoroethylene). The physical properties of this polymer are unmatched for the application, notably its water resistance, dielectric properties and long-term temperature aging. We also use oxygen-free alloys in our heating elements to give them greater longevity. The dual heating elements are braided with a durable ground shield and then coated with a highly visible blue water resistant PEX polymer jacket. No one builds a better heating element wire than SunTouch.



12.You make different products, so which one is the best for my application?



SunTouch mats work great in thinset or self leveling mortar over frame floors or slabs. Normally rooms needing less than 150 square feet of heated area with square corners are the best for SunTouch mats. They are usually covered with tile and used in bathrooms and kitchens. Coated WarmWire does the same thing, but it costs less, installs with straps and can also be used in showers. (Note: older, uncoated versions of WarmWire are not rated for shower use). Rooms needing more than 150 square feet of heated area and/or rooms with angles or arcs are good for WarmWire as it easily molds itself to unusual shapes. If your floor is cold and you have access from below in a crawl-space or unfinished basement, you can install SunTouch UnderFloor mats between your floor joists to warm the tile, stone or wood floors above.



13.Specifically, how is WarmWire different than SunTouch Mats?



Mats install faster in rectangular spaces and everything is preset for you. Mats add a fiber reinforcing to the thinset mortar and that makes your floor stronger. The mats have blue heating elements coated with a water resistant PEX polymer that makes them suitable for installation in a shower. The heating elements are factory-woven into a coated polyester mat with optimal 2.75 inch spacing and 12 watts per square foot output.



WarmWire costs less per square foot than the mats and the installation works well with unusual room shapes. So, WarmWire is more popular in larger areas or rooms with angles, curves, nooks, or tight spaces that don't fit well with mats. You can adjust the spacing of WarmWire to match the heat loss from the room.




14.What's the minimum/maximum wire spacing for WarmWire?



The WarmWire strap can hold down heating elements at 2 inch, 2.5 inch or 3 inch spacing. 2 inch spacing is suggested for rooms with high heat loss and concrete slabs. Use insulation below the floor if possible. 2.5 inch spacing is the most common spacing for rooms like baths, kitchens, living and basements with moderate heat loss. 3 inch spacing is best for rooms with low heat loss or hallways or large areas that are heated with heat ducts. Never space WarmWire closer than 2 inches or farther apart than 3 inches.



15.How much SunTouch mat or WarmWire do I need?



Use the new SunTouch Product Calculator. For many projects, one mat is enough, but a project can use multiple mats wired in parallel to warm larger areas with a limit of 15 amps of load on a single control.


16.Will the SunTouch system raise my floor height? How much?



Figure 1/8 to 3/8 inch depending on the installation method. Here are three examples:



1. Most installers use a 1/4 to 3/8 inch notched trowel to apply thinset mortar. If thinsetting and setting tile directly over the heating elements, figure 1/8-1/4 inch of increased height.

2. If you skim coat thinset over the heating system first, let it dry, and then thinset the tile, figure 1/4-3/8 inch added thickness.

3. Or, you can apply 1/4-3/8 inch self-leveling thinset to cover the heating elements and then cover with a finished floor covering material like a laminate.

If you install SunTouch UnderFloor between floor joists, the finished floor height will not change.



17.So, how much more thinset will I need for a SunTouch floor?



A safe estimate is to plan on using 60% more thinset than would normally be needed with a cold floor.


18.What kind of floor coverings can I put over my new radiant floor?



If you embed the heating elements in mortar, or if you install SunTouch Underfloor, you can use many kinds of floor coverings. The most popular warm floors are tile and stone. If you cover the heating elements with a self-leveling thinset, you can install laminate, floating, or glue-down hardwood flooring.



19.Are there floor coverings that don't work well over a radiant floor?



Nail-down floors won't work for obvious reasons. Vinyl flooring may deform and discolor on top of the heating elements. A pad and carpet will insulate your radiant floor so you might be disappointed with its performance. Rubber and cork floors also have higher insulating values so you may not be pleased with the warmth. Bamboo is a type of grass and you should check with the manufacturer to make sure it is rated for elevated temperatures. Although the temperature at the surface of a radiant floor should not exceed 85° F, the temperature at the bottom of the finished flooring could see temperatures of 90-110° F.



20.Do I need to put insulation under my SunTouch floor?



Insulation will reduce heat loss and improve your response time during warm-up periods. If you can get it under the floor framing or under your thinset (follow Tile Council of North America guidelines), insulation is a good idea. There are a number of products made to work under thinset floors, so check your local flooring distributor or dealer. In the case of SunTouch UnderFloor, insulation below the mat, between the joists is essential.



21.Can I install SunTouch in a shower floor?



Yes. Both SunTouch mats and WarmWire (coated only) are UL listed for installation in a custom shower floor or bench application. Refer to the SunTouch installation manual and WarmWire installation manual for further instructions.



Please note: Uncoated WarmWire is NOT listed by UL for installation in a custom shower or bench application.



22.Do you recommend a control to manage my radiant floor?



Yes. A SunTouch SunStat control has GFCI protection and a floor sensor to set the floor temperature. It has a system on/off switch that comes in handy and some models have programmable features to turn the system up and down, automatically, based on the entered schedule.


23.How much load can a SunStat handle?



SunTouch SunStats are dual-voltage thermostats (120 VAC and 240 VAC) that are rated for up to 15 amp service. They can handle up to 150 square feet of heated area at 120 VAC (15 Amps) or 300 square feet at 240 VAC (15 Amps). For larger areas that need one control, simply add a SunStat Relay for another 15 amps of heated area.


24.Where's a good place to locate a control?



Put the control above (or near) the spot where your power leads leave the floor. Put it in a UL listed, extra-deep switch box between 54 and 60 inches from the floor or at a height mandated by your local building code. Pick a wall that isn't in direct sunlight or on an exterior wall.


25.Can I buy directly from the manufacturer?



No… and it's not because we don't appreciate your business. Local distributors and dealers offer real value in your local area. Their experience, common sense, inventory choices and accessory products will make your project go much easier.


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SunTouch Installation FAQ's

1.Can I install SunTouch directly on plywood?

Yes, SunTouch can be installed directly on plywood if it is covered with at least 3/8 inch of mortar. It is a good idea to coat the plywood with a primer that is compatible with your brand of polymer modified mortar. If you are installing a thinset tile floor over plywood, consider first putting down a layer of cement "backerboard". Then, secure SunTouch to the backerboard and cover it with a latex or polymer modified mortar and then a finished tile or stone floor. In all cases, install the tile floors according to the Tile Council of North America guidelines.


2.I'm using a tile reinforcing system made my Ditra. Do I intall SunTouch mat under or over their product?

Their instructions indicate that heating elements are always installed under Ditra. However, when used on a concrete slab, heating elements should be installed over Ditra.



3.What type of thin-set/self leveler should I use when installing SunTouch Systems?



Use a latex or polymer modified thin-set mortar and apply it with a 3/8" notched trowel. You may also cover the heating elements with a self-leveling compound that you mix on the jobsite. Stay away from pre-mixed mortars, adhesives and quick set self-leveling compounds.


4.Can I cut the mat to make it fit my area?

Yes. Roll out the mat until you come to an obstruction. Cut the orange weave, and flip the mat to cover the next part of the floor. Repeat until you have covered the area you want to warm. Never install the mat on top of itself and never cut the blue heating element for any reason.



5.I have an unusual space in my bathroom. How can a mat cover that area?

You can shape the mat (see above) and you can pull out the heating element from the mat and glue it to the floor to fill in small areas.


6.Can I cut the heating element if I have too much?



No. That will ruin the mat. Each cable is built with a specific ohm (resistance) value, so the length must remain as it came from the factory.


7.Then what can I do if I have too much heating element on the job?



If you find you have too much heating element, you can always use of some of the excess next to the toilet or other areas you planned to leave unheated. You can run the loose heating elements as close as 2 inches to each other, but stay away from the toilet ring. If your mat is too large for the project, don't roll it up in the wall; that will cause dangerous overheating. Return the mat for one that is perfect for your project.


8.Can I shorten the shielded power lead? Can I shorten the sensor wire?

Yes and Yes. After you have pulled the shielded power lead and the white sensor wire into the control box in your wall, you will probably have some left over. You can cut off the excess and make the connections to the SunStat. Never cut the heating element wires or the sensor probe (the bulb at the end of the wire).

9.If I have heating elements left over, can I cut them or leave them in the wall?

No and Never. Never cut the heating elements. Always embed the mat and WarmWire heating elements in mortar in the floor and that includes the factory splice that joins the heating elements to the power leads. Never put heating elements or factory splices in the wall.


10.The power lead is a little thicker than the mat. How do I install that?


Power leads are secured to the floor and this includes the factory splice to the heating elements. Only the shielded power leads go into the wall and up to the junction box. You can use a router or chisel to make a groove in the floor for the power leads and factory splice if needed and then you can hot-glue the factory power lead splice in the groove.



11.What is a LoudMouth and do I need one?



The LoudMouth monitors your heating elements during the installation. If they are damaged, a light comes on and an alarm sounds so you can stop work and take steps to fix the problem. A LoudMouth can monitor three sets of heating elements at a time and it should stay on as long as the heating elements are exposed on the job site. A LoudMouth is worth the money.


12.Why should I use both a ohm meter (multimeter) and a LoudMouth?



Because these work well together. The ohm meter tells you the resistance (ohms) is up to factory specifications and the LoudMouth sounds an alarm if you damage the wire during installation. The ohm meter will also show a change in resistance if a wire is severed, but it doesn't sound an alarm. So, our advice is to use both devices when you install your radiant floor.


13.I am checking my resistance levels with a digital ohm meter (multimeter) and I am getting "OL" (open line) or I (infinite value), or no value between my power lead ground wire and each of the other wires. Is this normal?



Yes. If any resistance is measured between the green tagged wire (ground) and load wires, this would indicate a short-circuit, meaning damage to the heating elements. Be aware that auto-ranging multi meters will read your body as a circuit if you touch both test probe tips with your fingers.



14.If I cut or damage the heating element, can it be repaired?

Never cut the blue heating element for any reason. If during installation, you damage it, you can call our toll free number at 1-866-592-8169 and you can purchase a "Heating Wire Repair Kit". These kits should be installed by a licensed electrician.


15.So, how do I avoid damaging the heating elements?



Use special care when you trowel mortar over SunTouch. Cover the SunTouch with cardboard when it is exposed, to minimize damage from jobsite traffic. We suggest you use the plastic SunTouch CableTrowel when you apply mortar over SunTouch.


16.What's a CableTrowel?



The CableTrowel is a lightweight and durable notched blade that applies a 3/8" layer of combed mortar over your heating elements. Installers like the light weight and the fact that it cleans easily. Most important, it doesn't damage the heating elements like sharp metal trowels.



17.Do I need a GFCI in my circuit box to supply power for the SunTouch system?



The National Electrical Code requires GFCI protection for an electric radiant floor. The SunTouch SunStat has a built-in GFCI so you don't need an additional one in your circuit box.


18.I forgot to install the sensor, what can I do?



You can shatter and carefully remove one tile directly below the SunStat control location and then carefully chisel out a spacefor the sensor. Or, you can carefully remove the grout between two tiles. Then install the sensor wire and probe in the gap and re-grout the joint. Don't cut the heating elements with your chisel and don't install the probe right on top of the heating elements. Try to locate the probe between them.



Or, you may be able to carefully drill a small pocket into the bottom of a wood subfloor below the heated area and seal the sensor probe into this pocket.



You may also be able to switch to the built-in Air Temperature sensor in the SunStat by changing the options to "Air Sensing" mode or the timed "Regulator" mode. This works, but it is less accurate than the floor sensor.


19.I've got my SunTouch mat, but I can't find the control sensor.



Your sensor is located in the packaging of the SunStat thermostat. It's a loose coiled, white colored wire.


20.How do I secure WarmWire strap to a slab?



Drilling holes and fastening the strap with screws is an approved method. If you have backerboard over plywood, you can use nails or screws to hold the strap. The fastest and easiest way, however, is to spray the back of the strap with high-strength spray adhesive. Hot glue is a good alternative to spray adhesive. We also include double-sided tape in our kits (or you can purchase it separately), and this works well, especially over concrete.



21.How do I insulate an existing slab before I install SunTouch?



Some kinds of anti-fracture or crack-isolation membranes have minimal insulating properties. They are secured to the slab and then you put WarmWire or SunTouch mat on top. At least a good 1/4 inch insulating material will help reduce the heat losses into the slab below. Thicker insulation material tends to have a better R-vaule. Check with your local flooring dealers for products that are appropriate for radiant floors.


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SunTouch Operation FAQ's

1.Your manual says I'm supposed to wait 30 days after installation to turn my SunTouch system on. Why?



Mortar requires 28 days to cure completely. If you turn on the heating elements before it is cured, it will shrink, crack and pop up your tiles. Refer to the instructions on the bag of masonry or call the manufacturer.



2.How much will my radiant floor cost to operate?



Your cost will depend on how many hours you warm your floor and your cost of electricity. The SunTouch Product Calculator will give you an estimate based on an average usage.



3.What's a good temperature to set my radiant floor at?

Use your control to find a temperature that feels good to you. Start at 80° F and then adjust to your comfort.


4.What keeps my floor from overheating?



SunTouch controls have floor sensors and high temperature limits to keep the floor from getting too warm. Most users would not want to exceed a surface temperature of 85° F and many wood and laminate floor manufacturers want a limit of 82-84° F. Refer to the wood or laminate manufacturer for their recommended maximum floor temperature.


5.Does it take a long time for the floor to get warm?



From a cold start, the system takes a while because it's warming up the whole mass of the floor. Our digital controls help with this because it "sets-back" the temperature to a lower level, but not completely off. When the room is ready for the "comfort" temperature, the control will warm the floor up quickly. On average, this takes 20-45 minutes. Insulation below the floor warming system will reduce your warm-up time.


6.What could go wrong with SunTouch products?



The installation manual lists several things that could cause, prior to installation, harm or damage to the product. Typically, SunTouch is in greatest danger on the jobsite where sharp tools and construction traffic can damage a heating element. Once the floor covering is installed on top of the SunTouch, there is very little that can harm it.


7.What kind of support do you provide?


Call our toll free number from the U.S. and Canada at 1-866-592-8169 from 8 AM to 5 PM Central Time, Monday through Friday. Our engineers and customer service people are here to answer your questions. Watch the installation DVD's and read the installation manual which has a trouble-shooting chart near the back and call if there are any questions.


8.How do I explain my SunTouch floor to my neighbor over the fence?


From Alaska to Florida, people spend a lot of time in bathrooms on cold tile floors. SunTouch is a simple, low cost way to start your day with warm feet.