There are numerous electric floor heating brands systems on the market which utilize the same or nearly the same technology for heating various floor types such as ceramic, porcelain and natural stone tile, engineered wood, laminate and others, using electrical conductor cable. These systems are usually available in a form of either cable on a spool, or in a form of a rolled fiberglass mat with heating cable attached to it at a particular spacing. Mat dimensions and cable spacing may vary my manufacturer and for comparison reasons, the total sq. ft coverage of the mat is used for calculation purposes.
With floor heating mats, the cable spacing is pre-determined, and therefore cannot be adjusted during the installation process. Depending on the power output, mats can come with 2”, 3” or 4” cable spacing. In other words, heating mats have a fixed Watts (or BTU) output per square foot.
Floor heating cable, on the other hand, can be spaced according to the areas’ heating needs. A HeatTech radiant floor heating system with cable spaced at 3” will output 12Watts per square foot, but when cable is spaced at 2”, the system will output ~15Watts per square foot.
When facing the choice between a system with 12W or 15W per sqft heat output, the following should considered:
1. A typical output of a residential hydronic radiant heating system is within 25-35 BTU per square foot, with 40 BTU being a rare occasion for older homes and buildings with poor insulation.
2. 12W per square foot equals approximately 41 BTU per square foot (optimal heat output with enough backup power).
3. 15W per square foot equals approximately 51 BTU per square foot (30-100% above typical heating needs).
The answer is rather simple - as seen above, 12W/sqft system is ideally suited not only for creating warm and comfortable floors, but for whole house heating applications as well. 15W/sqft systems often output more heat than needed and may increase operating costs up to 20% as well as provide unnecessary stress on the equipment due to frequent cycling.
For further and more detailed comparison of the 12W and 15W heating systems, click here.