Radiant Floor Heating Buying Guide - Ferguson Home

Winter months can be particularly cold when your home has bare tile floors, or even wood plank. Accent rugs can add comfort but if your home needs a little extra warmth to get your toes through until spring, radiant floor heating is the answer. Not only can radiant heating warm the floors, it warms the air above it, saving on the energy bills by replacing forced-air heating with a more effective heat distribution.

With competitive price and timely delivery, Mufeng sincerely hope to be your supplier and partner.

There are a few important things to keep in mind when considering installing heated floor systems anywhere in your home, from the kitchen to the back bedrooms. From choosing the type of radiant floor heating that is best for your home layout, to balancing the heated floor costs, we break it all down for you in this guide.

What Is Radiant Floor Heating?

Also called in-floor heating, or underfloor heating, radiant floor heating provides a safe method of warming the floors and walls of the home rather than circulating air. The novel notion of heated floors warming a building has been in use in one form or another for thousands of years, but modern design technology has made it more reliable, safer, and affordable in the last century.

Radiant flooring can be added under floating floors or even grouted tile.

Today's heated floor systems can be installed under carpeted floors, wood or laminate planks, or the classic tile to make every room in the house comfortable, year-round. The different types of heated floor installation methods and power sources make a heated floor an affordable home improvement project that can boost the resale value at the same time. 

Whether a heated tile floor or a heated concrete floor, a heated floor system transfers heat through the floor and up into anything it touches, as well as gradually into the air. Heat naturally rises so when a floor tile or laminate board is heated, the heat that doesn't transfer into another object will warm the air above it continually and consistently. 

Unlike with forced air heating, a radiant floor heating system makes no noise and is completely invisible under the flooring with no need for extra venting. A heated floor can be added in a remodel to any room of the house or built-in on a new design to save money on the electric bill over time.

Advantages of Radiant Floor Heating

Whether you live in a colder area, or would like to add seasonal comfort under the cold tile or cement floors, an upgraded radiant floor heating system can simplify and improve your daily routine in many surprising ways.

Family and pet-friendly radiant flooring systems add year-round comfort.

Radiant heat flooring removes the surface chill by setting the floor to the same temperature as the human body. Warmer floors are particularly in demand for those facing problems with chronic ailments such as arthritis or diabetes, and are a worthwhile investment when remodeling with aging in place in mind. Because the floor can be kept at such a specific temperature with no visible or accessible burners, broilers, or hot air, it is even safe for kids and pets, too.

A heated tile floor is allergy friendly and easily maintained, and it keeps the room warm without requiring the use of dust-ridden, forced-air heating systems blowing allergens into and around the room. The energy is used to most efficiently heat the room from the ground up rather than allow the heat to be lost in the ductwork where the air has had a chance to cool.

Controlling an in-floor heating system is as easy as controlling any modern thermostat.

Electric floor heating is easy to operate, using programmable thermostats with all the same features as the controls of any other heating or cooling system. Syncing the underfloor heating system to the off-peak hours of your energy provider can even save you money on energy bills over time. Set the floor to heat during the local power company’s low-demand hours and turn it off during the day; the residual heat will cut the surface chill long after the system has gone idle.

These and the many other advantages to adding in-floor heating to the home add up to a cozy, welcoming home experience every day. Adding an underfloor heating system during a remodel is a good way to boost the home’s resale value, whether you’re planning to sell soon or will still be living in the home for many years to come.

How Does Radiant Floor Heating Work?

Radiant floor heating works by transferring warmth through surrounding objects, moving and radiating the heat through the floor. This happens utilizing a location-appropriate heating source that can reach between 85 degrees and 145 degrees Fahrenheit safely enough to transfer warmth through the surrounding floor material - such as concrete - against the underside of the floor to radiate up to the surface and into the room.

Electric floor heating allows you to set the ideal floor temperature using a thermostat, similar to the thermostat of a whole house, forced-air heating system. The in-floor heating systems can be installed in different configurations so you can choose the type that works best with your home’s layout and your project budget.

Staple-up emitters attach to the underside of the floor or subfloor and transfer the heat into the boards or other flooring above. They may require construction of a secondary subfloor to attach to, and they work well in homes where the floor can be accessed via basements or raised crawl spaces. Mount them to the underside of the floor between the joists and connect them to zone thermostats.

Tubing installed in channels chiseled out of concrete floors can utilize either hot water or hot air to radiate enough heat to warm the surrounding concrete and help evenly disperse the heat into the floor above.

The types of tubing can include:

• Copper tubing
• Polyethylene (PEX) rubber
• Rubber tubing

The tubing can be installed flush over flat concrete under a subfloor to the same effect if your project budget or timeline doesn’t allow for drilling channels into a concrete slab. For new builds, the channels can be planned ahead of time to make the heated floor installation even easier.

Floor mats and cable installation membrane allow the sheathed wire heat sources to be routed across the subfloor to be covered with the final floor surface. Rather than installing them to the underside of the floorboards, the electric wiring over the mats or installation membrane allows you to determine your own zones according to the layout of the space.

When looking at how to install heated floors, it’s clear that there are many different ways to make the flooring fit the demands of your floor, but all of them perform essentially the same functions. It’s all about customizing your project to fit your home.

Types of Radiant Floor Heating

The oldest forms of heated floors used hot water running under buildings to warm the floors, though it was very costly to use for private homes. With the different modern methods used to heat floors, every home heating solution is customizable and affordable. There are three common types of radiant floor heating to choose from.

Add in-floor heating under any new flooring project.

Heating mats utilize sheathed copper or nichrome wires woven into and throughout heat-conducting plastic webbing, creating a mat that can then be connected to a thermostat to best control the heat they produce. These floor heaters can be installed over any subflooring. A thin layer of cement over the subfloor will help to distribute the heat more consistently over the whole floor and radiate warmth across the final flooring surface, whether it is tile floor, planks, or carpeted.

The plumbing system runs heated water through embedded tubing under the floor.

Hydronic heat circulates water through a water broiler and along the floor through tubes. The channels the tubes are installed in radiate heat out into the floor, up to the surface. This type does require access to the plumbing and the installation of a broiler.

Radiant air flow forces hot air through the channels in the floor, similar to how hydronic heat works. It requires very hot temperatures and the air doesn’t escape the channels under the floor. Air-based systems work best when they are embedded in concrete slab flooring to allow the cement to absorb the heat and help retain a consistent temperature across the floor surface.

While the materials used to prepare the floor help protect the different technologies from malfunctioning over time, it is important to ensure secure and proper installation. These can all be installed as do-it-yourself projects, or enlist the help of a contractor or electrician for the wiring.

There are many ways to heat a home that don't require the use of a forced-air system.

All of these floor heating options can also utilize reflective insulation and aluminum heat diffuser plates to help direct and retain the heat. Infrared panels and other developing technologies can be used to augment the flooring or provide other heat sources in the room. Look for the heating solutions that best fit your home.

Types of Radiant Floor Compatible Floor Coverings

There are many kinds of flooring that can be used with effective radiant floor heating systems. You can even use outdoor floor heating under stone to help keep the walkways safe around the outside of the home in freezing weather. Certain flooring types transfer the heat better than others, so keep in mind that flooring can either block the heat or transfer it. The most common flooring materials can be broken down into three main categories.

Radiant flooring systems can be installed in any room of the house.

Tile flooring encompasses both ceramic and porcelain tile types. Tile floors consistently retain the heat and spread it across the floor surface most effectively. Both are very reactive to external heat sources, but the kiln process of making porcelain tiles can help porcelain hold the warmth of an underfloor heating system longer and allows the thermostat to be set a little lower for best results.

Many types of flooring are compatible with radiant floor heating systems.

Wood flooring can also be used with radiant floor heating, though it is recommended to use laminate flooring to avoid problems with the planks shrinking as they dry out from the regular heat exposure. Plank flooring, whether wood or laminate, transfers the heat without distributing it quite as well across the entire surface, due to the variance in the grain and materials. It absorbs and retains the heat well and the entire floor will be comfortable to touch, though some areas may be warmer than others.

Pets and family alike enjoy the benefits of in-floor heating.

The other common type of flooring used is carpet. Thinner carpet with a dense padding is better to transfer heat to the surface. Carpet easily traps the heat in the floor, with more layers of air built in between the touchable surface of the carpet and the heat source under the floor. It transfers the heat as effectively as the other floor types, but the heating source under the floor may need to be set at a higher temperature in order to be felt as strongly on the surface.

Sizing Radiant Floor Heating Systems

The size of the room is only one piece of the puzzle when determining the size of the underfloor heating system. It requires starting with the square footage of the room, and then determining the placement of the permanent features in the room. The underfloor heating system wiring can then be planned to work around the areas that will be most easily accessible and used more often.

Avoid placing radiant floor systems under inaccessible areas to save money on the installation up front costs. The permanent features to avoid can include any cabinetry or semi-permanent furniture or walls, such as a kitchen island. These features will trap heat rather than transfer it to an exposed surface and effectively waste the energy spent to heat it. 

The size of the room and the size of the system that is ultimately planned out will determine the power capacity required for the floor heater. One way of minimizing the power consumption is to separate the floor to be wired into smaller sections, or system zones, which can be one uniform heating type or can rely on multiple types of radiant heat as needed. 

Different rooms or system zones can be controlled via different thermostats.

These zones can be controlled by a single thermostat, which sets a single system temperature for the entire floor. Especially when controlling multiple heating types, the underfloor heating can also be wired as a two-temperature system by connecting the different zones to multiple thermostats. This provides greater temperature control from room to room and can better monitor the home’s energy consumption over time.

Costs, Energy Savings, and Compatible Power Sources

When budgeting for a radiant floor project, the three upfront factors to consider are:

• The cost of the radiant heat system.
• The cost of the installation labor.
• The cost of the appropriate flooring material.

While the costs of the heating and flooring materials will depend on the coverage area, the labor costs for installation will depend on the amount of time spent preparing the project. Building a new home allows for the radiant heating system to be planned into the floor installation from the start, while drilling and creating channels in an existing concrete slab floor as part of a remodel can present complications and time delays along the way. It’s important to match the type of system to the requirements of the location so that the project can be handled efficiently and result in the best possible heating system for your floor.

Another consideration when planning and budgeting for radiant floor heating costs is the cost to operate the system in your home. This is largely dependent on the amount of energy your current heating system uses and the type of power system that runs the larger appliances in your home. In-floor heating systems can entirely replace the regular, daily use of a central heating, forced-air system, especially in homes with standard ceilings. 

Radiant floor heating systems can be utilized with all home power systems to best meet the usage demands of your home. Whether your home runs on natural gas or electric, look for a heated floor system that works with your home appliances’ primary power source. If your current heating system is powered by natural gas, it’s easy to find a complementary floor heating system, so that you can simply switch the heating options. 

As the heat rises from the floor, it heats the air more effectively at the exact height where people occupying the room can experience the benefit. The heated air isn’t cooled by circulation up to the cold air at the ceiling and then back down, as it is with a forced-air system. The heat is dispensed and spread more efficiently across the entire floor, with fewer cold spots to make up for, saving on energy usage. It results in less energy use, at a lower cost. 

Anything blocking the floor surface can either transfer the heat provided by a radiant floor heating system, or it can block it. Plan the floor layout carefully to be sure that the heating system will be installed in the locations where it will be accessible, because when the heat is trapped rather than allowed to radiate out, it can create hot and cold spots, which could result in using more energy than needed.

By SunTouch® A division of Watts Water Technologies, Inc.

The perfect solution for nearly every type of floor covering.

Introducing

UnderFloor mats are the perfect solution for nearly every type of floor covering.

These special mats warm existing floors without having to replace the floor coverings.

If you have access under a floor, simply staple UnderFloor mats between the joists.

SunTouch UnderFloor is a safe and efficient electric floor-warming product for interior applications. It is intended only for installation under a wood subfloor in residential and light commercial installations. It is not designed for other purposes such as roof snow melting.

Any use or installation of this product other than what is stated in this installation manual will void the Limited Warranty.

SunTouch UnderFloor is designed to deliver approximately 10 watts/sq. ft. of floor area. The temperature of the warm floor is dependent on how well the floor is insulated, as well as the insulating value of the flooring materials. If the joist space is sealed against air leakage, exterior rim joists are insulated, and the underneath side of the floor is insulated, most floors can be heated up to 15°F warmer than they would otherwise be.

Due to the insulating value of carpet, carpeted floors may not achieve the same temperature rise. The floor may or may not achieve this temperature rise, and no representations are made regarding the performance of any system.

For best results, install, un-faced fiber glass R-1 9 or R-1 3 (or equivalent) below the mat.

Do not insulate below the mat with more than R-1 9, and no more than R-1 1 total on top of the subfloor, including all floor coverings, rugs and other items placed on top. SunTouch UnderFloor can be used to heat a room, as well as warm the floor, provided the heat loss of the room falls within the mat’s capabilities. A designer must determine if the output from the SunTouch UnderFloor is enough to match the heat loss of the structure.

The SunTouch UnderFloor Mat

The mat is composed of a heating cable, a foil “radiator” to make a radiant surface, and a set of power leads for connection to the floor-sensing control. These mats are manufactured in sizes suitable to heat joist bays spaced 12″, 16″, and 19′.2″ on center.

Mats are rated either 120 VAC or 240 VAC. Select the mat length to fit into the joist space available. Multiple mats can be used to fill a larger area, however they must be wired together in parallel (not in series) if they are to be connected to the same control. NEVER combine 1 20-VAC mats with 240-VAC mats.

Part 1: Designing a SunTouch UnderFloor System

In general, SunTouch UnderFloor should be installed in all floor areas where floor warming is desired. It can be installed to either warm the floor or to heat the space. If SunTouch is being installed to heat the space, first per form a heat loss calculation. Use RadiantWorks® or a similar program to calculate the heat loss of the room(s).

SunTouch can be expected to provide approximately 34 BTU/hr/sq.ft. of mat. This assumes the mats are installed per this manual, including the use of proper insulation techniques.

Make sure insulation is installed as shown on page 10. There must be a “dead air space” for UnderFloor mats to be effective This output also assumes a floor covering other than carpet and pad. The output will be greatly diminished with a carpet floor covering and/or the lack of proper insulation.

Determine how much Mat is needed for the Installation

To determine how much mat is needed, take one of two approaches:

1. For a rough estimate, multiply the wall-to-wall area by 75% – 80%. Convert this to linear feet of mat and select from the lengths of mat shown in the next pages.

2. For an accurate measurement, look under the subfloor to see where mats can be stapled. Looking carefully at each joist bay, measure the length of open area in that bay that can receive a mat, and select the mat from the table that fits the space.

Remember that these mats cannot be cut shorter to fit, nor modified in any way to fit multiple joist bays. Do not include in these measurements areas that contain items that would obstruct installation of the mat (return air ducts, supply ducts, light fixtures, etc.).

Where mats are not installed, the floor above wilt not gets very warm.

Wiring Multiple Mats Together

Each mat is designed to be installed in only one joist bay.

The mats cannot be cut shorter to fit a shorter joist bay or modified in any way to fill multiple Joist bays However; more than one mat may be installed in a Joist bay where there are barriers such as cross bracing. A typical installation is shown below.
Since several mats wilt be required to warm the floor area, the mats must be wired together in parallel (not in series) at a junction box below the floor, then electrical wire fed from there up to the floor-sensing control box. Select mats for the easiest wiring possible. If all the power leads end up at one end of the room, it will be much easier to wire them together in the junction box.

The junction box must be accessible after all finishing work is completed. Be sure to position the mats so that this is possible

Mat Voltage Requirements

SunStat controls are dual voltages 120/240 Volt.

Select either SunStat Pro programmable control or SunStat Non-Programmable control with either 120-VAC mats or 240-VAC mats. BUT NEVER mix 120-VAC mats with 240-VAC mats.

Observe these general voltage guide lines:

1. For areas totaling up to about 190 sq. ft. (about 15 amps), use 120-VAC mats with a 1 20-VAC SunStat

2. For areas exceeding about 190 sq. ft. and up to about 350 sq. ft., use 240-VAC mats with a any of SunStat to have mats totaling 14 amps or less.

3. Use 240-VAC mats with SunStat dual Voltage 240- VAC SunStat Relay control system for mats totaling more than 14 amps at 240VAC.
Regardless of the voltage requirements in a particular installation, make sure the circuit breaker can handle the load. Follow all electrical codes for determining the size of the breaker.

Floor-Sensing Controls

To control the SunTouch UnderFloor system, install either a programmable or non programmable control, floor-sensing SunTouch SunStat or SunStat with Relay system. The sensor should be installed per instructions.
Please reference the SunTouch catalog, or contact us at for more information.

These effective, UL-Listed mats deliver 10 watts/sq. ft. of floor area (about 34 BTU/hr/sq. ft.).

UnderFloor mats will warm wood, vinyl, laminates, or tile floor coverings.

With UnderFloor mats, most floors can be heated up to 12° to 15°F warmer than they would otherwise be.

Carpeted floors will not warm up as much as other floor coverings due to the high insulation value of carpet and padding. You may experience a temperature rise in the floor of only a 6° – 10°F, which may or may not meet your satisfaction. Insulation installed below the mats is essential to complete the installation.

Consider these benefits of UnderFloor mats:

1. Easy staple-up installation between floor joists.

2. Manufactured in nearly 40 different lengths in 12″, 16″, and 19.2″ widths. Mats of any size (same voltage) may be combined to heat any type of room.

3. 120-VAC and 240-VAC models for small to large projects.

4. Highest-quality heating wire using Aramid reinforcing, ETFE high-temperature insulation, and oxygen-free copper alloys for corrosion-resistance, temperature- resistance, abrasion-resistance, and longevity.

5. Shielded and fully grounded 10-ft. power lead for safety and jobsite durability (longer lengths available on request). Power leads are color-coded for 120 VAC and for 240 VAC.

Caution: Do not install UnderFloor mats in mortar or cement, or install them in the same control zone as SunTouch mats or WarmWire cables. These products have different heat output, and are manufactured for different applications.

Part 2: Electrical Service Rough-In

Circuit Over current Protection and GFCI Protection

The SunTouch mat must be protected by a ground fault circuit interrupter (GFCI). If the mats are directly powered through the SunStat Pro or SunStat controls, these already have an integral GFCI to protect the mats (do not install a GFCI type circuit breaker to supply a SunStat or SunStat Relay system, because the respective GFCIs may conflict and cause problems).

If a different type control or relay is used that does not have a built-in Class A GFCI, an indicating- type GFCI circuit breaker must be used to protect the mats.
This GFCI breaker serves as a local disconnect.

NOTE: Follow all local building and electrical codes.

It is recommended that the system be installed on its own dedicated circuit, directly from the circuit breaker panel.

However, small systems may be able to tap into an existing circuit. Consult an electrician.

Make sure there is adequate capacity for the mat(s) as well as any other items that may use this circuit.

The mat(s) should not be installed in a circuit with another GFCI (breaker or outlet), lighting circuit (low voltage, halogen, or other types that use ballasts or transformers that can interfere), or motor circuit (exhaust fan, hot tub, etc.) due to possible interference which can cause the

GFCI on the control to false-trip. The circuit breaker protecting the mat(s) must be no larger than 20 amps.

Load the circuit breaker with no more than the following: 12 amps on a 15-amp circuit breaker, 16 amps on a 20-amp circuit breaker.

Additional circuit breakers will be required for larger loads than these.

Select mats so that no more than 15 amps are run through a SunStat control

120 Volt – UnderFloor Mat Sizes,Amperage Draw, and Resistance Ranges.- 12 O.C. Mat Size Amperage Draw Resistance Range (ohms) 12″ x 5.5 ft. 0.4 247 – 302 12″ x 8 ft. 0.6 167 – 204 12″ x 10.5 ft.. 0.9 121 – 148 12″ x 13 ft. 1.1 91 -119 12″ x 16 ft. 1.3 80 – 98 12″ x 19 ft. 1.5 67 – 82 120 Volt – UnderFloor Mat Sizes,Amperage Draw, and Resistance Ranges.- 16 O.C. Mat Size Amperage Draw Resistance Range (ohms 16″ x 4 ft. 0.4 258 – 315 16″ x 6 ft. 0.6 173 – 211 16″ x 8 ft.. 0.8 126 – 154 16″ x 9.5 ft. 1.0 101 – 123 16″ x 12 ft. 1.3 82 – 101 16″ x 14 ft. 1.5 69 – 85 16″ x 16 ft 1.7 63 – 78 16″ x 18 ft. 1.9 53 – 65 16″ x 19.5 ft 2.1 45 – 56 120 Volt – UnderFloor Mat Sizes, Amperage Draw, and Resistance Ranges.- 19.2 O.C. Mat Size Amperage Draw Resistance Range (ohms 19.2″ x 4.5 ft. 0.7 170 – 207 19.2″ x 6.5 ft. 0.9 127 – 155 19.2″ x 8 ft.. 1.0 103 – 126 19.2″ x 9.5 ft. 1.3 83 – 102 19.2″ x 11.5 ft. 1.5 71 – 87 19.2″ x 13 ft. 1.7 63 – 78 19.2″ x 14.5 ft.. 1.8 54 – 66 19.2″ x 16 ft. 2.1 45 – 56

Large Systems on one Floor-sensing Control

For systems that are too large to directly power through one SunStat, but must be operated by one floor sensing control, use the SunStat with Relay control for best performance.

Contact a flooringsupplyshop.com or the factory for more information.

A contactor (relay) may also be used. Consult an electrician concerning the use of a contactor, and be sure to protect it with a GFCI breaker.

Install Electrical Boxes

SunStat box.

Decide on the location for the floor-sensing control. Usually this will be in the same room as the floor being warmed, but it can be mounted almost anywhere as long as it is not in a confined space where airflow is restricted. To reach this box with the mats, the mat power leads and the sensor wire leads can both be extended if needed with the appropriate size wire at a junction box.

The control electrical box may be a single-gang plastic deep box, but be sure to follow all electrical code requirements for box fill, grounding, etc. when determining the correct box for a particular application.

The control box should be located on interior walls, typically 60″ from the floor, according to code requirements.

NOTE: The SunStat sensor wire can be up to 50 ft. long, extended with 22- or 24-AWG wire.

240 Volt – UnderFloor Mat Sizes,Amperage Draw, and Resistance Ranges.- 12 O.C. Mat Size Amperage Draw Resistance Range (ohms 12″ x 10.5 ft.. 0.4 500 – 611 12″ x 16 ft. 0.6 336 – 411 240 Volt – UnderFloor Mat Sizes,Amperage Draw, and Resistance Ranges.- 16 O.C. Mat Size Amperage Draw Resistance Range (ohms 16″ x 8 ft. 0.4 521 – 636 16″ x 12 ft. 0.6 362 – 443 16″ x 16 ft 0.8 253 – 310 16″ x 19.5 ft 1.0 207 – 253 240 Volt – UnderFloor Mat Sizes, Amperage Draw, and Resistance Ranges.- 19.2 O.C. Mat Size Amperage Draw Resistance Range (ohms 19.2″ x 6.5 ft. 0.4 526 – 643 19.2″ x 9.5 ft. 0.6 359 – 439 19.2″ x 13 ft.. 0.9 256 – 313 19.2″ x 16 ft. 1.0 207 – 253 19.2″ x 19 ft. 1.3 167 – 204

Other junction boxes: It is highly recommended that a separate steel electrical junction box be mounted below the subfloor or in the wall in a location to which the mat power leads can be routed.

A separate wiring drop
can be made from the control box down to this junction box. This makes it much easier to install the system.

Bottom Plate Work

Drill a hole up through the wall bottom plate to route the power wiring from the control box to the mats below the floor.

Rough-in Wiring

Install electrical wiring from the power source breaker to the control electrical box, and then to the junction box below the floor for the mat leads.

The company is the world’s best 3D Underfloor Heating Module supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.

Leave 6″–8″ of extra wire at the control box and junction box. Refer to the wiring diagrams in Part 6 for assistance.

Diagram showing Method 1 for installing the floor sensor into the subfloor.

Install SunStat Sensor

A floor sensor comes with the SunStat control and must be installed correctly to control the floor temperature.

Remember to locate the sensor in a floor where a mat is located.

The following are recommended methods for installing the sensor. Other equivalent methods may be used.

Before installing the sensor, make sure to test it with an ohmmeter.

Method 1. Since a sensor may be difficult to install in some existing floors, the sensor may be placed under the subfloor.

However, keep in mind that the temperature the sensor gives will not be a true floor surface temperature and the floor-sensing control may need to be adjusted accordingly.

Drill a hole through the bottom plate of the wall to route the sensor wire.

Feed the sensor wire down from the control box through the floor. (A fish-tape may need to be used in order to do this.)

The most accurate method is to drill a 3/4″–1″-long hole at an angle into the bottom of the subfloor (drilling at an angle prevents puncturing through floor surface). Locate this hole in a joist bay directly over where a mat will be installed, about 2″ from the joist. Insert the sensor into the angled hole and seal it with adhesive. Insulate the sensor with additional “blueboard” or fiberglass insulation, 1″–2″ thick and 6″ square, adhered and sealed under the sensor. This will isolate the sensor from the heated joist space and give a truer floor surface temperature.

Method 2. If it is not possible to drill a hole to set the sensor in the subfloor, it may be held flat to the subfloor with a nylon wire clip.

Locate the sensor in a joist bay directly over where a mat will be installed, about 2″ from the joist. Insulate the sensor with additional “blueboard” or fiberglass insulation, 1″–2″ thick and 6″ square. This will help isolate the sensor from the heated joist space.

Method 3: Remove the grout 1/4″ to 1/2″ deep. Install sensor. Reinstall grout over the sensor and sensor wire.

Method 3. If possible, install the sensor directly into or under the floor covering area.

If the floor surface is tiled, a grout line can be removed and the sensor laid into this grout line.

Drill a hole into the wall behind the baseboard trim area and directly below the control electrical box.

Feed the sensor through the knockout, down to the hole that was drilled near the floor, and out into the floor above where the heating mat will be installed.

Locate the sensor at least 1 ft. from outside walls and near the center of a joist space.

Complete the rest of the installation before covering or re grouting over the sensor.

Sample Kitchen Layout Using UnderFloor Mats

Each UnderFloor mat is designed to be installed in only one joist bay. The mats cannot be cut shorter to fit a shorter joist bay or modified in any way to fill multiple joist bays.

However, more than one mat may be installed in a joist bay where there are barriers such as cross bracing or blocking.

In this kitchen layout, four 9.5′ × 16″ and eight 4′ × 16″ mats are required to warm the floor area.

The mats are wired together in parallel (not in series) at junction boxes below the floor, then electrical wire is fed over to the FloorStat control.

Select mats for the easiest wiring possible. If all the power leads end up at one end of the room, it will be much easier to wire them together in the junction boxes. Junction boxes must be accessible after all finishing work is completed.

Part 3: Install the UnderFloor Mat

Important – Read

Do not allow the foil radiator of the mat to be mounted such that it contacts metal objects such as

nails, staples, metal pipes, heating ducts, and joist straps. Keep the mat at least 2″ away

from recessed fixtures (lights, etc.), ventilation openings, and other openings.

Keep the mat at least 8″ away from the edges of outlet boxes and junction boxes used to mount surface lighting fixtures.

Keep the mat at least 2” away from recessed fixtures (lights, etc.), ventilation openings, and other openings.

Keep the mat at least 6″ away from heat-sensitive items such as toilet rings, flexible ducting, and other items rated less than 194°F (90°C). Consult manufacturers of those items.

REMEMBER:

Pay careful attention to areas where ductwork, wiring, or other items do not allow the mat to be installed. Keep in mind that where mats are not installed, the corresponding floor area above

will not get very warm.

Before installing the mat, inspect all joists as well as the underside of the subfloor for nails, screws, or other sharp objects that protrude into the joist cavity.

These items can damage the mat,and must be removed, cut off, or bent flat against the underside of the subfloor or the side of the joist(s).

Do not staple, cut, or damage the foiled heating portion of the mat in any way.

The fiber mesh of the mat is the portion that will be used to staple the mat to the joists cavity.

1. Measure between the floor joists where mat(s) will be installed.

Measure the width of the mat selected to fit between these joists. The difference between these measurements determine how much mat mesh remains for stapling to each side of the joists.

Because the distance between floor joists can vary, taking these measurements will help ensure the mat will be centered between the joists. It is also prudent to test fit the mat by holding

the mat up into the joist cavity.

2. If the mat begins near the rim joist, measure about 6″ out from that rim joist.

This will allow enough room for the mat power leads, and will prevent unnecessary heating of the wall cavity above the floor.

3. Measure 2″ below the subfloor and mark the joists on both sides of the joist cavity.

4. To help hold up the power leads while installing the mat, fasten one Nail Tite over the power leads

5. Hold the mat up along one joist and begin stapling the mat mesh along the 2″ mark from the subfloor. Staple every 4″ to 6″ for about 2 ft. to get started.

6. At the other end of the mat, place a nail into the joist at 2″ below the subfloor. Hang the fiber mesh of the mat onto the nail. This will make it much easier to staple the rest of the mat.

7. Continue stapling the mat mesh at 2″ below the subfloor, every 4″ to 6″.

Then remove the nail at the end that held it up.

Power Lead Installation

If not already done so, mount a junction box below the subfloor within reach of the mat power leads.

Install more than one junction box, if needed, for larger jobs.

The junction box must remain accessible in accordance with electrical codes, so consider the location of the junction box carefully should the ceiling be finished after installation of the mat(s).

Route the power leads from the mat(s) to the junction box following all electrical and building codes using

Junction box with multiple sets of mat lead wires, connected in parallel, and connected to the

power supply. conduit and additional electrical boxes where required.

Junction box with multiple sets of mat lead wires, connected in parallel, and connected to the power supply.

For multiple mats, follow all electrical codes concerning “box fill” maximums.

Connect the leads in parallel (black-to-black, white-to-white), and not in series.

Connect the mat leads to the power drop from the control electrical box or

SunStat sub control, or contactor.

Again, do not overload the control.

The SunStat and Relay control must not be loaded with over 15 amps of mats.

Part 4: Final Wiring

The mat power leads and sensor wire connected to the control at the electrical box.

Install the Control

Install the control(s) for the mats according to the wiring diagrams provided with the controls.

(See Part 6 Wiring Diagram).

Connect the power supply leads, the power drop to the mat junction box, and the floor sensor wire to the SunStat. Follow proper wiring procedures.

It is a good idea to over wrap the wire nuts with electrical tape to further secure the wires into the wires nuts before pushing the control back into the electrical box.

Test the System

After the controls are installed and connected, energize the system briefly to test operation of all components.

Refer to the installation sheets provided with the SunStat for proper setting.

Without floor insulation, the mat will not heat the floor. When the SunStat calls for heat to the mat, the mat will begin to feel warm to the touch within 1 to 2 minutes or so. If this does not

occur, re check the SunStat settings, wiring connections, and power supply.

Apply the Warning Label

Apply the Radiant Heating Warning Label (included with this manual) to the control or nearby location.

Part 5: Install the Insulation

REMEMBER: Proper insulating and sealing of the floor cavity is necessary for the performance of SunTouch UnderFloor mats.

Install R-13 to R-19 fiberglass insulation below the mat. Gently press the insulation up to the mat for best results and secure in place with rods, staples, or other method.

A gap between the insulation and mat is acceptable but will not give the best heating results.

Make sure to insulate at the end of all heated joist cavities. Install insulation vertically in these areas to seal the ends of the heated joist areas or, 6″ after the mat “stops” in a joist space, push the insulation up tight against the subfloor and staple to the subfloor.

This ensures that no heated air can escape from the heated joist space. If this is not done, much heat will “escape” horizontally through band joists, rim joists, exterior walls, and open ends of joist spaces, and the floor will not warm as it should.

Seal openings around pipes, waste lines, ducts, joist blocking, and all other gaps with silicone caulking or urethane foam.

Wiring Diagram

Typical Electric Wiring Diagram with FloorStat Control (120 V)
Dedicated 120-V, 20-amp (maximum) circuit (must be GFCI protected unless a GFCI SunStat is
used)

All electrical work must be done by a qualified licensed electrician in accordance with local building and electrical codes, and the National Electrical Code (NEC), especially Article 424, Part IX of the NEC, ANSI/NFPA70 and Section 62 of CEC Part 1.

Typical Electric Wiring Diagram with FloorStat Control (240 V)

Dedicated 240-V, 20-amp (maximum) circuit (must be GFCI protected unless a GFCI SunStat is used).

All electrical work must be done by a qualified licensed electrician in accordance with local building and electrical codes, and

the National Electrical Code (NEC), especially Article 424, Part IX of the NEC, ANSI/NFPA70 and Section 62 of CEC Part 1.

Typical Electric Wiring Diagram with SunStat Control and Contactor(s) (240 V)

Dedicated 240-V. contactor circuit is GFCI Class A or B protected.

All electrical work must be done by a qualified licensed electrician in accordance with local building and electrical codes, and

the National Electrical Code (NEC), especially Article 424, Part IX of the NEC, ANSI/NFPA70 and Section 62 of CEC Part 1.

How to Connect the LoudMouth Monitor to the Mat Power Leads

Illustrations showing how to connect the LoudMouth monitor to two mats (left) ,and how to connect the LoudMouth to three mats (right). The LoudMouth can monitor no more than three mats simultaneously.

Do NOT leave the power leads connected in “series” like this when making final wiring connections; the mats will not heat sufficiently. When making final wiring connections, mats must be wired in parallel.

Part 7: Troubleshooting Guide

If problems arise with the SunTouch UnderFloor mat or its related electrical components, please consult this trouble shooting guide.
If not qualified to perform electrical work, it is highly recommended that a qualified, licensed electrician be hired.

Any electrical troubleshooting work should be performed with the power removed from the circuit, unless otherwise noted.
Although this troubleshooting guide is provided to assist with problems experienced with a SunTouch floor warming system, results are never guar anteed. SunTouch does not assume any liability or responsibility for dam age or injury that may occur from using this guide.

Problem Possible Cause Solution Mat resistance measurement is outside the range printed on the nameplate label. An analog ohmmeter (using a moving needle) was used to take the reading. Obtain a digital ohmmeter able to read 0 to 20,000 ohms and re measure the resistance. If measurement shows an open or short circuit, the heating wire has been damaged. Record resistance between all wires and contact the manufacturer. If measurement is just a little low or high, room temperature has affected the resistance. Make the room temperature 75° – 85°F, or contact the manufacturer. The resistance measurement could be from more than one mat wired in series, or wired in parallel. Either will provide false resistance readings. Make sure resistance measurements are for only one mat at a time. When connecting more than one mat to the control, multiple mats must be wired in parallel (i.e., black to black, white to white). The ohmmeter may be set to the wrong scale. For instance, the 200 K ohms scale measures up to 200,000 ohms. The ohmmeter should typically be set to the 200 ohms scale, with the exception of mats having a rating above 200 ohms on their nameplate label. If the resistance reading is outside the range printed on the nameplate label, contact the manufacturer. Floor is not getting warm. Mat has been damaged. Measure mat resistance. Check for both “open circuit” and “short circuit” as detailed earlier in this manual. If damaged, record resistances between all wires and contact the manufacturer. GFCI has tripped, indicated by a light on the control. Light may be labeled “GFI”, may be below the words “Stand by”, or on the button labeled “Test”. Check for loose wire connections. Reset the GFCI on the control or circuit breaker. If it trips again, check for a short circuit in the mat as detailed earlier in this manual. If mat is damaged, record resistance between all wires and contact the manufacturer. If mat is not damaged, replace the GFCI control. Also see “GFCI conflicts” below. Incorrect voltage supplied, or mismatched electrical components used. Measure “line” voltage, then measure “load” voltage. Both 120-V mats and controls have black and white leads. 240 V mats have black and blue leads, and 240-V controls have black and red leads. Concrete slab floor. Surface temperatures rise slowly in a slab. If, after 5 to 8 hours of heating, the floor is not warmer to the touch, check for mat damage (see “Mat has been damaged” above). Measure “load” voltage/amperage to mat. Floor heats continuously. Mats are wired in “series” or “daisy chained” (end-to-end). Multiple mats must be connected in “parallel” (or black-to black, white-to-white). Sensor is loose or broken. If control has a digital display, it may indicate “LO”. SunTouch controls have a floor sensor. Pull the sensor wires loose from the control and reinsert them. If this does not solve the problem, measure resistance across the sensor wires. For a SunTouch control the resistance should be between 17,000 ohms (at 55°F) and 8,000 ohms (at 85°F). See sensor wire resistance values in this Manual Incorrect wiring. The control was “bypassed” when it was wired to the power supply. Make sure wiring connections are correct. Consult the wiring diagram on the back of the control, the instructions that came with the control, or the wiring diagram in this manual. Defective control. Return control to dealer for replacement. Floor temperature shows “HI” or may show temperature over 100°F. Floor sensor is not wired properly, or is located incorrectly. Make sure only one floor sensor is connected to the control. Also see “Sensor is loose or broken” above. Control is not working correctly. If a programmable control, the programming may be incorrect. Carefully read and follow control programming instructions. Incorrect voltage supplied, or mismatched components used. Test voltage, verify parts. See “Incorrect voltage supplied” above. Floor sensor is not wired properly, or is not working properly. Make sure only one floor sensor is connected to the control. Also see “Sensor is loose or broken” above. Loose connection(s) on line side and/or load side of control. Remove and reinstall the wire nuts at each connection. Make sure the wire nuts are tight. Check all connections back to the breaker. Defective control. Return control to dealer for replacement. Control is not working at all. No power is supplied. Check circuit breaker. Measure voltage at the control. Check all connections between breaker and control. Floor sensor is not wired properly, or is not working properly. Make sure only one floor sensor is connected to the control. Also see “Sensor is loose or broken” above. Defective control. Return control to dealer for replacement. GFCI conflicts and false-trips. More than one GFCI on the circuit. GFCI units will sometimes trip when there is nothing wrong with the equipment on the circuit, but when there is more than one GFCI. Reroute power to avoid having more than one GFCI on the circuit. An electric motor or a ballasted light source is sharing the circuit with the mat. Electric motors and other electrical devices can cause a GFCI to false-trip. Run a dedicated circuit to the floor warming system.

www.suntouch.com

Click here for SunTouch VIDEO Library

SunTouch vs. Product A – SunTouch vs. Product B

SunTouch Floor Heating Mat Links

SunTouch Mats Spec and installation – SunTouch Mat Specification – Underfloor Spec and Installation

SunTouch Floor Heating Spool Links

SunTouch WarmWire Installation Guidelines – SunTouch WarmWire Strap – WarmWire Installation Guidelines – WarmWire Order Instruction and Information

Heating Controls Links

Programmable SunStat Spec – Owner’s Manual Programmable -SB – Owner Manual Non Programmable

– SunStat Non Programmable Spec – SunStat Relays Control – LoudMouth Operating Instruction

Misc SunTouch Links

Want more information on Underfloor Heating Staple Gun? Feel free to contact us.