Month: October 2012

By Steven Bench

I received a telephone call this morning from a prospective customer wanting to
understand the difference between Heat Trace, Heat Tape, and GutterMelt. After
explaining the differences to him it occurred to me that perhaps others are confused so I
decided to write this article.

Heat Trace and Heat Tape are generic terms for a family of electric heating cables that
are designed to keep pipes from freezing, maintain the temperature of the contents of
pipes and melt snow and ice off of roofs and in drains, rain gutters and downspouts.
Some of the products in this family are designed to be installed inside of pipes and others
are designed to be wrapped around the outside of pipes, valves, and instrumentation.
Obviously the Heat Trace and Heat Tape products designed for rain gutters, downspouts
and on roofs are designed to be exposed to the elements including the rays from the sun.

Within the family of electric heating cables referred to as “Heat Trace” or “Heat Tape”
are Constant Wattage cables and Self Regulating cables. As you might have already
concluded Constant Wattage cables always put out approximately the same watts per
linear foot regardless of the temperature of their surroundings. The wattage output
per linear foot of Self Regulating cables on the other hand, varies dramatically as the
temperature surrounding the cable changes. As a matter of fact the wattage output of a
length of Self Regulating cable may vary as the temperature surrounding the cable varies
along its length.

The various brands of Constant Wattage Heat Trace or Heat Tape cables come in many
different quality levels and price points and are generally fixed in length. Design
longevity, temperature tolerance, and wattage output all dramatically affect quality and
price. Within the Constant Wattage segment of Heat Trace or Heat Tape, prices range
from less than a dollar to several dollars per foot, and life expectancy ranges from a year
or two to 10 or more years. The wattage output of Constant Wattage cables varies from a
few watts per foot up to 50 plus watts per foot.

Self Regulating cables are generally cut to length in the field products and like Constant
Wattage cables they are available in many different quality levels and price points. Like
Constant Wattage cables, the quality and price of Self Regulating Heat Trace or Heat
is dictated by the design longevity, temperature tolerance, and wattage output. These
cables generally have wattage outputs ranging from 3 to 24 plus watts per foot in a
certain medium (air, ice, water, etc.) and at a certain temperature.

Given that multiple outputs and many different types of cables are available on the
market much is to be gained to contacting an expert in the field when determining which
cable will best satisfy the objectives of your project.

By Steven D. Bench, Heatizon Systems

California’s Building Energy Standards, Title 24, Part 6 allows for the use of electrical radiant floor warming and electrical radiant space heating products whenever said products meet the definition of “supplemental heating.”

So what exactly is “supplemental heating?” According to the Building Energy Standards for the state of California “supplemental heating” is heating which is: (a) not the primary space conditioning system (defined as that system used in energy compliance analysis); and, (b) installed in an area that is also directly served by the primary space conditioning system. Of course common sense and the Building Energy Standards require that the primary space conditioning system have sufficient capacity to condition the entire building or home.

In other words, anytime the primary space conditioning system does not have sufficient capacity to condition the entire building or home, and/or the primary space conditioning system does not directly serve the space where the electrical radiant floor-warming or electrical radiant space heating product is to be installed, then said products are not considered “supplemental heating” and they must be included in the energy performance analysis to comply with the Building Energy Standards. As a result, the energy use of electrical floor warming and space heating products installed in areas such as bathrooms, that do not have supply vents from the primary space conditioning system, must be included in the energy performance standards compliance analysis.

The fact is that electric resistance space conditioning is difficult to justify as the primary space heater in California. The reason for this is that California uses source energy as the measurement for efficiency. As a result, even though electric products generally have energy efficiencies of 99 percent or greater, the efficiency of electric radiant floor warming and space heating products are reduced by the inefficiency of generating and delivering the electricity to the point of consumption.

The good news is Californians can enjoy the comfort and cleanliness of electric radiant floor warming and space heating anytime they have a primary system that has sufficient capacity to condition the entire space and the space is directly served by the primary system.