Planning your SunTouch floor

You make different products, so which one is the best one 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.

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 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.

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.

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.

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.

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.

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.

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.

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.

Can I install the SunTouch in a shower floor?

Yes. Both SunTouch mats and WarmWire 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.

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.

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.

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.

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.

Please note: This FAQ document is designed to answer common questions. Refer to the product's installation manual or appropriate instructions and warnings regarding installation, use and maintenance.