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How to Calculate 'Heated Area'

How to Calculate 'Heated Area'

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Traditional electric radiant floor heating mats and cables, like those made dim drawingby 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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