Underlayments for Floor Heating Frequently Asked Questions

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.

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.

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.

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.

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. 

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.

One thermostat can control multiple heating mats/cables as long as all the heating elements are using less than 15 amps:

TempZone™ will cover aprx. 120 sq. ft. for 120V systems and 240 sq. ft. for 240V systems on one thermostat.

Environ™ will cover aprx. 150 sq. ft. for 120V systems and 300 sq. ft. for 240V systems on one thermostat.

Slab Heat will cover aprx. 90 sq. ft. for 120V systems and 180 sq. ft. for 240V systems on one thermostat.

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. 

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 ThermalSheet as your underlayment. 

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 WarmlyYours ThermalSheet, provide a thermal break between a subfloor and the heating elements, which can help prevent the concrete from acting as a “heat sink” and increase energy efficiency. ThermalSheet has a 1.5 R-value, and it offers crack isolation of up to ¼”. 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.

Cork flooring can be used with floor heating if the r-value is under 1. You will need to find the r-value of the flooring you choose and let your account manager know during the design stage. Cork flooring should have a low r-value to minimize trapped heat.

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 ThermalSheet synthetic cork is a good choice because of its high 1.5 R-value and moisture resistance. 

A Warmly Yours indoor floor heating system should not be installed with a GFCI breaker because GFCI protection is built into the thermostat and power module.  And while it's not always required, we strongly recommend a dedicated circuit for each thermostat and power module to limit the occurrence of ground fault nuisance tripping caused by multiple GFCI devices on a circuit. The amperage of a breaker would depend on the amp draw of the heating system. For example, a TempZone Flex Roll (which provides approximately 15 watts of energy output per square foot) that is providing 15 square feet of heating coverage will draw only 225 watts ( 1.9 Amps), so a 15 Amp circuit would suffice.  Always size breakers according to your local Electrical Code requirements. 

An area where large furniture will cover the floor should have enough clearance underneath to allow air to circulate. Any areas where floor heat may be trapped (rugs, box bottom furniture), let your sales rep know so we can design an installation plan around these areas.