Underlayment for Heated Floors


While not every floor heating project requires an underlayment, they are particularly useful for projects where there is concern about heat loss to the subfloor or when subfloor issues threaten to compromise the integrity of relatively fragile flooring types like tile, marble, or stone. WarmlyYours offers 2 different underlayment products: Prodeso Cable Installation Membrane and CeraZorb®.


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Which Radiant Heating Underlayment Option is Right for You?

Selecting the perfect floor heating underlayment will depend on information that is unique to your project like the type of subfloor you're installing over and the flooring type you'll put over the heating system.

The Prodeso Cable Installation Membrane is an uncoupling membrane that can only be used with the TempZone Floor Heating Cable. The membrane provides long lasting uncoupling and crack isolation benefits for tile, marble, and stone floors. The benefit of uncoupling is that it allows for a small degree of foundational movement (which occurs when a house “settles”) without causing the tiles in the floor to crack, break or “pop.” The idea behind crack isolation is that it stops cracks (up to a certain size) in the subfloor from “telegraphing” upwards into the floor which can cause extensive damage. An additional benefit of the membrane is that it can greatly decrease installation time as it allows an installer to complete most residential installations in a single day. Check out our design guide on Floor Heating with Prodeso Membrane and Tiles.

CeraZorb® is a synthetic “insulating” underlayment that has a higher degree of thermal resistance (R-value of 1.5) than cork. CeraZorb® is also the recommended underlayment for heating on top of a concrete slab and is often paired with our TempZone and Environ electric floor heating elements.

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Underlayment Solutions

CeraZorb® Synthetic Cork Underlayment


Description

CeraZorb is lightweight, synthetic cork underlayment system that is specifically designed for setting tile and stone and is an excellent insulation choice under our TempZone™ and Environ electric floor heating elements.

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Features
  • Heat and cold resistant, and will not rot, support mold and mildew, or absorb moisture.
  • Stable and durable, remaining unchanged after repeated impact loads.
  • Can be set under tile and stone, over any acceptable sub floor.

Available Sizes
  • 2’ x 2’ sheets (12-pack) for a total coverage of 48 sq. ft.
  • 4’ x 4’ sheets (20-pack) for a total coverage of 320 sq. ft.

Prodeso Installation Membrane


Description

Prodeso Cable Installation Membrane is an uncoupling membrane that is designed to be used with TempZone electric floor heating cable. The unique design of the membrane allows for greatly accelerated installations of floor heating.

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Features
  • Energy-efficient, radiant heat installation membrane.
  • Unique design allows quick and easy installation – in and out in one day.
  • Flexibility to adjust to any room size and requires no waiting.

Available Sizes
  • 3’ x 16’ roll for a total coverage of 54 sq. ft.
  • 3’ x 49’ roll for a total coverage of 162 sq. ft.

Frequently Asked Questions


How many square feet of floor heating can be connected to one thermostat?

One thermostat can control multiple heating mats/cables as long as all the elements are using less than 15 amps. For TempZone™ Flex Roll systems for example that would be maximum of 120 sq.ft. for 120V systems and 240 sq.ft. for 240V.

How can I make my basement warmer?

A floor heating system can work as a supplemental heating source and make the basement warmer. If more heat needs to be added to the room, you can experiment with setting the floor heating thermostat to higher temperatures.

Should I add insulation before installing electric floor heating and how will that affect the system's performance?

When installing electric floor heating over a concrete slab, an insulating underlayment like CeraZorb is highly recommended to ensure efficient operation, faster heating times and warmer floor temperatures.

Will electric floor heating help with moisture issues like mold and mildew?

Yes, the drying effects of electric radiant floor heating will reduce the humidity coming from the slab, which is the largest source of moisture.

Can electric floor heating be installed under a vanity?

Electric radiant floor heating should not be installed under permanent fixtures that may trap heat. However, if the vanity or cabinets are "floating" or are on legs, then a floor heating system may be installed under it.

How much does it cost to heat a bathroom floor with electric floor heating?

A typical bathroom floor can be heated for about a quarter a day with electric radiant floor heating.

How are hydronic and electric floor heating systems different?

While both hydronic (heated water) and electric floor heating systems perform a similar function by providing radiant heat from beneath your floor, they do differ in some pretty crucial ways. Typically, using hot water instead of electricity will result in lower operational costs but significantly higher investment and maintenance costs. This usually means that hydronic heating systems are reserved for new construction projects (where it is easier to incorporate the boilers and pumps needed to operate the system) and electric floor heating is often used for remodeling projects in bathrooms, kitchens, etc. To learn more about the differences between these systems, check out this post

Is a floor heating underlayment always required?

No, an underlayment isn’t always necessary. 

However, there are some situations in which the use of an underlayment would be required, such as heating over a cement slab (where an insulating underlayment would most likely be required). When heating over a cement slab, our recommendation is to use CeraZorb as your underlayment. 

How do I figure out how much underlayment I’ll need for my floor heating project?

The best way is to use our Radiant Floor Heating Quote Builder tool. It’s a great way to get an estimation by simply providing project information like room size and subfloor type. 

Which floor heating underlayment is best for a high-moisture installation like a bathroom?

Typically, an uncoupling membrane like Prodeso will be best for this application because it can be paired with accessories to effectively waterproof the subfloor. 

However, if you have a cement subfloor, then CeraZorb synthetic cork is a good choice because of its high 1.5 R-value and moisture resistance. 

How are insulating underlayments different from uncoupling membranes?

Insulating underlayments and uncoupling membranes share some key characteristics like providing crack isolation benefits. But they are separated by their primary functions.

Insulating underlayments, like CeraZorb, provide a thermal break between a subfloor and the heating elements, which can help prevent “heat sink” and increase energy efficiency. This can be particularly beneficial if you are trying to heat a room above a cement slab or above an unheated garage. 

Uncoupling membranes, like the Prodeso membrane, are great for protecting relatively fragile floor coverings like tile from foundational movement. They also allow for faster installation times than many other types of floor heating. 

How much does it cost to run an electric floor heating system?

The answer to this question will depend on a whole host of variables related to electric floor heating, including, but not limited to, the run time (for supplemental heating, we usually recommend between 4-8 hours per day), the electric radiant floor heating system you're using, the total square footage, and your local electrical cost. Typically, the cost is just a few cents a day. 

To figure out how much electric floor heating might cost to run for you, make sure to use our interactive Operating Cost Calculator. 

How does electric floor heating compare to central or forced air heating?

Typically, electric floor heating is used as a supplemental heat source but in some cases, it can be used as a primary heat source. Electric floor heating is more energy efficient, less prone to spreading dust and allergens, and easier to control from room to room. Air-based heating systems can be used for both heating and cooling and can be a good way to control air quality in the home with regular maintenance. 

For a more in-depth answer to this question, check out Your ‘Cheat Sheet’ for Radiant Heat vs. Forced Air

Do I have to replace my floor to install electric floor heating?

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 Radiant Panels, which are wall-mounted and use infrared technology to provide supplemental heating. 

How does electric floor heating work?

Electric floor heating works by having an electric heating cable installed underneath the flooring (embedded or floating, depending on the system and floor type), which is then wired to a special thermostat (either one specifically designed for electric radiant floor heating, like a WarmlyYours’ nSpiration Series control, or a third-party thermostat). When turned on, the heating cable emits heat upward through the flooring which is then radiated throughout the room, heating all solid surfaces. 

What voltage does WarmlyYours floor heating systems utilize?

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.

How do I work with my electrician to install WarmlyYours electric floor heating?

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.

What type of flooring can I install along with an electric floor heating system?

WarmlyYours’ TempZone™ product is most commonly installed under tile, stone, and marble flooring, but can also be installed under many other popular floor covering options such as hardwood, vinyl and linoleum. We also have our Environ system, which is an electric floor heating product as well and is specially designed for installation under carpet (in the U.S. only), laminate and floating wood. WarmlyYours can accommodate any flooring type with either of the electric radiant floor heating products that we offer. If your flooring type isn't listed here, just give us a call at (800) 875-5285 and we will be happy to discuss it with you.

What temperature will my heated floor reach?

The temperature of your floor can range anywhere between 75°F to 95°F. The floor's actual temperature will depend on a number of factors including the amount of heat loss that the room experiences as well as the room’s configuration. For instance, the warmth contained in a two story entry way would likely be less than that of a smaller, more enclosed area such as a bathroom. In a bathroom that is located on the second floor of your home or over another floor in your home that is typically heated, the temperature of your heated floor should easily reach a comfortable temperature of 85 degrees Fahrenheit, if the electric floor heating system is installed correctly. For the heat loss calculation for your specific room, you can access the Heat Loss Calculator or you can call us at (800) 875-5285 and a Customer Service Representative will make the calculation for you.

What is the total power/amperage that the electric floor heating system draws and does this system need a dedicated circuit?

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, the system will draw less than 3 or 4 amps. If you have a larger area over 120 square feet of heated space, then you may 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.

If I have extra cold lead wire, can I trim off what I don't need for my installation?

Yes. Unlike the heating cable for electric floor heating, the cold lead wires can be trimmed or lengthened with additional lead wire which can be purchased from WarmlyYours.

How do I know if I am installing my electric floor heating system properly?

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.

Is electric floor heating safe and what about EMF?

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

How can I determine what I need for my floor heating project and how can I find out what my floor heating system will cost?

You can use the Instant Quote Tool, which gives you many options for your floor heating coverage. Use this interactive tool to design your room online and receive an instant quotation with product recommendations, rough-in and installation kits, cost of your control, etc. Planning your floor heating project is made easy when using our Instant Quote Tool.

Send us your floor plan or fax it to (800) 408-1100 and we will send you a quote, product recommendation and a free custom installation plan for your project.

Can I use electric floor heating as a primary heat source?

Yes, in most cases, an electric floor heating system can be effective as a primary heat source. However, our TempZone™ and Environ™ systems are most commonly used as a secondary heat source, providing floor-to-ceiling radiant heat to any room in your home where you desire more warmth and comfort.

If you are considering electric floor heating for an addition to your home, such as a sunroom where you have no other source of heat, WarmlyYours offers an innovative online tool which calculates approximate heat loss. This tool can help you to determine if a WarmlyYours’ electric radiant floor heating system will provide your desired comfort temperature throughout the year. You can access the Heat Loss Calculator or you can call us at (800) 875-5285 and a Customer Service Representative will make the calculation for you.