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How to Calculate 'Heated Area'

How to Calculate 'Heated Area'

dim drawingTraditional electric radiant floor heating mats and cables, like those made by SunTouch, Nuheat and Schluter-Systems, are resistance heating systems. This means that the wire in each size of the heating elements is individually designed to ensure it puts out the optimal amount of heat, and cutting the element shorter or splicing more material on to make it longer will cause the element to heat improperly and could potentially lower the lifespan of the system. This makes it especially important to ensure that you order the mat(s) or cable(s) that fit your area best. But don’t worry, we’re here to help!

The best way to determine what size mat or cable you need is to create a dimensioned drawing of the room, including wall-to-wall measurements, dimensions or built-in fixtures such as vanities and kitchen islands, and the location of any vents or drains. For bathrooms, also include a measurement from the wall behind the toilet to the flange or base of the toilet. Below is an example of a complete drawing.

From here, the process for determining which mat or cable you need depends on the product being installed.

 


SunTouch Mats

  • Start by calculating the square footage of the open area(s) (anything not covered by built-in fixtures or obstructed by vents or drains). This will give you what is commonly referred to as the “tiled area” of the room.

NOTE : SunTouch mats are safe (UL listed) for installation in showers, but it is recommended to use a separate

mat or cable in the shower, so calculate the main area and the shower separately when heating a bathroom.

  • While the mats can be installed close to toe-kicks, tubs, cabinets and showers, they should be 2-4 inches away from walls. To make sure you will have an adequate border, multiply the total tiled area by 0.9 to figure out the total heated area.
    • For bathrooms, subtract from the tiled area a section around the toilet flange large enough to keep the heating elements 6 inches away from the wax ring (usually 2-4 sq ft).
  • Finally, select the mat (or mats) that cover a square footage closest to your heated area. Remember, you can connect up to three mats to one thermostat so long as the combined amperage is less than 15.

WarmWire Cable

  • Start by calculating the square footage of the open area(s) (anything not covered by built-in fixtures or obstructed by vents or drains). This will give you what is commonly referred to as the “tiled area” of the room.

NOTE : WarmWire cables are safe (UL listed) for installation in showers, but it is recommended to use a separate mat or cable in the shower, so calculate the main area and the shower separately when heating a bathroom.

  • While the cables can be installed close to toe-kicks, tubs, cabinets and showers, they should be 2-4 inches away from walls. To make sure you will have an adequate border, multiply the total tiled area by 0.9 to figure out the total heated area.
    • For bathrooms, subtract from the tiled area a section around the toilet flange large enough to keep the heating elements 6 inches away from the wax ring (usually 2-4 sq ft).
  • Finally, select the cable (or cables) that cover a square footage closest to your heated area. Remember, you can connect up to three cables to one thermostat so long as the combined amperage is less than 15.

Nuheat Standard Mats

  • Look at the dimensions of the open area(s) in the room (anything not covered by built-in fixtures or obstructed by vents or drains). This is what is commonly referred to as the “tiled area” of the room. Select a mat or assortment of mats from the Nuheat Standard Mat section that best fit the tiled area without getting closer than 6 inches to the toilet flange and 2 inches from walls with baseboards.

 

NOTE : Nuheat mats cannot be cut or shaped, so if there is not a mat that fits the area, choose the next size down.


Nuheat Cable

  • Start by calculating the square footage of the open area(s) (anything not covered by built-in fixtures or obstructed by vents or drains). This will give you what is commonly referred to as the “tiled area” of the room.

NOTE : Nuheat cables are safe (UL listed) for installation in showers, but it is recommended to use a separate mat or cable in the shower, so calculate the main area and the shower separately when heating a bathroom.

  • While the cables can be installed close to toe-kicks, tubs, cabinets and showers, they should be 2-4 inches away from walls. To make sure you will have an adequate border, multiply the total tiled area by 0.9 to figure out the total heated area.3
    • For bathrooms, subtract from the tiled area a section around the toilet flange large enough to keep the heating elements 6 inches away from the wax ring (usually 2-4 sq ft).
  • Finally, select the cable (or cables) that cover a square footage closest to your heated area. Remember, you can connect up to three cables to one thermostat so long as the combined amperage is less than 15.

DITRA-HEAT

  • Start by calculating the total square footage of the room, including under built-in fixtures such as cabinets, kitchen islands and vanities. While you will not be heating this entire area, you will need to cover it with the DITRA-HEAT membrane, so keep this number handy.
  • Next calculate the square footage of the open area(s) (anything not covered by built-in fixtures or obstructed by vents or drains). This will give you what is commonly referred to as the “tiled area” of the room.

NOTE : DITRA-HEAT cables are safe (UL listed) for installation in showers, but it is recommended to use a separate mat or cable in the shower, so calculate the main area and the shower separately when heating a bathroom.

  • While the cables can be installed close to toe-kicks, tubs, cabinets and showers, they should be 3-4 inches away from walls. To make sure you will have an adequate border, multiply the total tiled area by 0.9 to figure out the total heated area.
    • For bathrooms, subtract from the tiled area a section around the toilet flange large enough to keep the heating elements 6 inches away from the wax ring (usually 2-4 sq ft).
  • Finally, select the cable (or cables) that cover a square footage closest to your heated area. Remember, you can connect up to three cables to one thermostat so long as the combined amperage is less than 15.
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Comments

  • Kevin
    Author: Kevin Posted: March 6, 2017

    If I measure and draw out my floor space. Can you figure out what I would need for my project? I am finishing off my basement and the tile areas I am thinking about heating.

    • Jacquelyn Sutterman
      Author: Jacquelyn Sutterman Posted: March 6, 2017

      Hi Kevin,

      Thanks so much for reaching out.
      Please do send us that drawing of your floor space & our quoting department will get back to you with a plan in 24 hours or less!

      Warm Regards,

      The Warm Your Floor Team

  • Ken K.
    Author: Ken K. Posted: March 11, 2017

    I am planning on installing your WarmWire in a bathroom in the basement that has a slab. If it is about 30 sq ft that I need to cover, how much wire do I need to cover it and utilize the programmable thermostat?

    Thanks,
    Ken

    • Jacquelyn Sutterman
      Author: Jacquelyn Sutterman Posted: March 13, 2017

      Hi Ken,

      The old WarmWire cables were spaced at 2.5" for standard heating or 2.0" if you wanted a little extra heat when going over a slab subfloor. Current WarmWire cable is spaced at 3.0" for standard heat and 2.5" for extra heat.

      If you are interested in standard heat, you will need a 30 sq ft cable. We recommend using a SunStat Command programmable thermostat to control your floor. If you'd like to use the closer spacing for more heat you'll need the 35 sq ft cable, which covers 29 sq ft at 2.5" spacing.

      Warm Regards,
      The Warm Your Floor Team

  • Bill L.
    Author: Bill L. Posted: March 14, 2017

    I would like to email the plans for the remodeled bathroom for an idea how much parts would be. Also, do folks typically run the warmer all the time? I am in Michigan the floor will be above a heated room. Using the warmer for tile comfort only the room has heat.

    Thanks, Bill

    • Jacquelyn Sutterman
      Author: Jacquelyn Sutterman Posted: March 14, 2017

      Hi Bill,

      You can email your plans to quote@warmyourfloor.com to get a formal quote on the materials that would be needed for your project. Simply include the drawing, your contact information, and your preferred product line if you have one.

      Most people use a programmable thermostat and set the system to run when they know people will be home and likely using the room. Occasionally customers will purchase non-programmable thermostats and leave them running continuously, but this leads to unnecessary energy costs. For this reason, the programmable option is always recommended.

      Warm Regards,
      The Warm Your Floor Team