There has been much debate over low voltage radiant systems versus line voltage radiant systems as radiant heat gains popularity in North America. The aim of this article is to dispel some of the myths surrounding the different kinds of systems.

Myth 1: Low voltage radiant systems are safer than line voltage.

Low voltage is low, so it makes sense that it’s safer, right? While this makes perfect sense initially, we have to take a closer look to find out the real answer. If your definition of safe is the chances of being hurt by voltage during installation, low voltage will give you a bit of a shock, but won’t cause lasting damage. The real question we should be asking is how durable is the cable against damage and how well is the cable insulated. Both line and low voltage snow melting systems are embedded in 4 inches of concrete, asphalt, or under pavers. When installed properly the embedded systems are not exposed and harmful. Some low voltage heating wires are NOT designed for embedment. These have only a thin layer of plastic and a heating element that is THHN/THWN wire. This wire is intended for interior use NOT in concrete, asphalt, or under pavers. Low voltage wires do not have ground fault protection, so electrical leakage can go undetected.

In contrast, line voltage obviously has higher voltage, which is why line voltage cables are built to withstand wear and tear, and are much more difficult to damage. If you do manage to damage a line voltage cable, don’t worry! Line voltage systems are equipped with ground fault protection (GFEP) breakers with a 30 milliamp trip. Which means the system will automatically shut off when it has reached beyond allowable leakage levels. What does this mean? Well for one you don’t need to worry about bodily harm, but you also don’t need to worry about potential fire hazard from a damaged cable. The bottom line: both line voltage and low voltage systems are safe to use.

Myth 2: Low voltage radiant systems cost less to run than a line voltage system.

It is true that low voltage radiant systems consume a lower amount of power, but this doesn’t mean it is less costly to run. Low voltage systems can actually be more expensive to operate because these systems generally produce 20 watts/sq ft (which is below ASHRAE standards). By producing less heat per square foot, it takes longer to heat the same area, thus increasing the cost and the time it takes to melt. Because of the decreased heat output, during heavier snow falls low voltage systems struggle to keep up with the snowfall, and have to remain on much longer. For this reason, ASHRAE has set forth watt standards for snow melting.

Line voltage systems are designed specifically for the environment in which they will be operating. These systems are made to produce the necessary watts (that meet ASHRAE standards) to melt snow in the most efficient time possible.

Some low voltage systems on the market have some distinct advantages over line voltage. Zmesh is low voltage, but does not rely on heat cables to generate heat. Instead it is constructed of a unique thin mesh that requires no embedding in thinset and can be installed directly under carpet pad, hardwood and even for use on your roof for snow and ice melting. The biggest advantage of Zmesh is that you can hammer nails into it without worry of damage!

Myth 3: Low voltage systems are easier to repair.

Both line voltage and low voltage cables are easy to repair. Simply remove the bad section of cable, add in a splice kit, cover it back over with whatever surface it’s in, and the system should operate as normal. You do not have to replace the entire cable or rip out the entire surface, only the area that is damaged. The location of the break can be identified by using devices such as the DEVItrace from Danfoss or a TDR, which uses radio frequencies and a “wand” to locate the damaged section of cable.

Myth 4: Low Voltage systems are more efficient.

Low voltage systems are NOT more efficient. Since these systems have a much lower output of heat per square foot; they take much longer to melt snow, especially during heavy snow storms and probably will not be able to keep up with the demand. Further increasing their inefficiencies, low voltage systems must have the electricity pass through a transformer and very thick power leads (2 gauge), which causes voltage to drop as it travels distance before reaching the heating element. Line voltage cables have the energy to go directly into heating, without the loss of power. Overall, both line and low voltage systems are more efficient than hydronic snow melting.

Myth 5: Low voltage systems offer a better warranty.

Some low voltage warranties are very deceiving. They boast of a 25 year warranty period, but when examined closer it is found that the 25 year warranty only covers the heating wire. As discussed earlier these heating wires are actually THHN or THWN, which can be purchased relatively cheaply at any hardware store.

Warmzone’s line voltage cable manufacturer’s warranty (Danfoss) covers up five times the cost of the original system which is intended to cover the cost and time involved in making repairs, not just the actual heating element itself.

Myth 6: Both systems provide sufficient heat.

Low voltage systems in most snow melting applications do not meet the ASHRAE standards. The minimum watts per square foot ASHRAE requires in North America is 32 watts per square foot. Popular low voltage systems on average are designed to produce approximately 20 watts per square foot and with extremely tight spacing will max out at 30, still below the standards ASHRAE has set forth.

Line voltage systems are designed specifically for the environment in which they will be operating. These systems are made to produce the necessary watts (that meet ASHRAE standards) to melt snow in the most efficient time possible.

Myth 7: Both systems are UL Approved.

Most low voltage snow melting systems are not UL listed. Warmzone’s line voltage systems are UL tested and approved.

SYSTEM WEAKNESSES

• THHN/THWN wire was not designed for concrete embedding. The outer jacket is soft and easily cut which will shorten its life.
• Low heat output – Does not satisfy ASHRAE requirements.
• Bulky and costly controls (transformer and control box are 100 lbs per 200 square foot zone).
• Warranty - only covers THHN/THWN wire. Control box is 1 year, transformer is 5 years.
• Slow to install - the transformer and control box are complicated and time consuming to install.
• Noise – transformers emit noise and location of them must be considered.
• Price – low-voltage systems are typically double the price of a comparable line –voltage system.

As radiant heating systems have gained popularity, a lot of fly-by-night manufacturers are trying to cash in on the recent boom. This sparked ASHRAE to come out with standards for radiant snow melting systems to prevent abuse from manufacturers. Most low voltage radiant snow melting systems don’t meet the ASHRAE standards for quality and efficiency. Unfortunately, not all consumers are aware of standards in the radiant industry and purchase faulty products unwittingly and end up with negativity towards radiant heating in general. Rest assured there are plenty of efficient radiant systems that will run smoothly for decades without needing any maintenance. Make sure to do thorough research before purchasing any products, which means checking for proper safety certifications and standards, and you won't regret it.  

When replacing a home heating system, there are a lot of questions that people have in regards to new home heating systems.  Here is a questions that was recently asked.

Q: My 1,200 square foot home used to be heated by a furnace from 1949 that ran at 25,000 BTU. Recently I changed the system to a newer, 7,000 BTU system. I thought this newer heater would be more efficient, but I find that it takes much longer to heat the house than the older system did. Is there something wrong with my furnace or do I need one that has a higher BTU?

A: It’s a good idea to replace old heating systems with newer, more efficient models. These new models can work just as well or better than old systems, but they do work differently. Where old furnaces could be turned on and heat the house within a matter of minutes, new heating systems can take longer. If you want your home to be warm at a certain time, set the heat to go on about 45 minutes prior to that.

Another important factor is whether your home is “weather-tight.” Make sure all doors and windows are properly sealed. If not, you may be losing heat at the same rate your heating system is producing it. Check with a heating contractor who can tell you whether the new unit is sized correctly for your home’s square footage.

Radiant heaters, as opposed to warm air systems (such as a forced air unit heaters), deliver the source of heat to the floor level, not the ceiling. And since warm air rises, heating the floors proves to be the most efficient means of heating living areas.

Radiant heaters or radiant energy is the oldest form of heating used to provide comfort and is the basis for all heating systems. Radiant energy is totally pure radiation and is absorbed by an object without physical contact with the heat source or by heating the surrounding air, as is the case with convective, forced air systems.

Under floor heaters were first used by the Romans. Initially the preserve of the rich, under floor heating became increasingly commonplace in public buildings and villas, particularly in the colder regions of the Roman Empire. The Roman system was based on hypocausts, comprising ducts that underlay the floor (itself built on raised brick piles) and flues that were built into walls. Hot air or steam from fires circulated up through this system, warming the floor and walls, with heat passing into the rooms.

More specifically, the floor was laid out as series of concrete slabs acting as radiant heaters supported by columns of layered tiles, with a furnace at the bottom of one exterior wall. By placing the fire here, the draught would take the radiant heat under the floor, and up through the walls to radiant heater chimneys located in the corners of the room.

Today we recognize the brilliance of the Romans and Koreans as early adopters of radiant heating, as the technology is still a desired method for delivering comfortable and efficient heat in our homes. Now we have radiant heaters using electric resistance cables that are constructed of highly rated materials and feature manufacturer warranties of up to 25 years.

About Warmzone
Warmzone provides consumers with energy-efficient, radiant heating solutions for homes and businesses. Based in Salt Lake City, Utah, Warmzone's electricians and radiant heat experts will help you determine the best radiant heating solution, ranging from electric heated floors to large commercial snow and ice melt projects. Send us a plan or drawings and we'll be happy to provide you with a FREE estimate and options for your roof heating and ice melting project.

If you’re in the market for a new home heating solution, you may be wondering what kinds of home heating choices are there? A majority of homeowners are probably most familiar with forced air unit heaters and might not realize that there are other options for heating a home – other options that are more efficient and even more comfortable. One such option are radiant heaters, which, as opposed to warm air systems, delivers the source of heat to the floor level, not the ceiling.

Radiant heaters or radiant energy is the oldest form of heating used to provide comfort and is the basis for all heating systems. Radiant energy is totally pure radiation and is absorbed by an object without physical contact with the heat source or by heating the surrounding air, as is the case with convective, forced air systems. Believe it or not, under-the-floor heaters were first used by the Romans. While under floor heating was initially reserved for the rich, it eventually became increasingly commonplace in public buildings and villas. This form of radiant heating was used particularly in the colder regions of the Roman Empire. The Roman system was based on hypocausts, comprising ducts that underlay the floor (itself built on raised brick piles) and flues that were built into walls. Hot air or steam from fires circulated up through this system, warming the floor and walls, with heat passing into the rooms.
Radiant Heaters Tip: Health experts agree that radiant heaters can help in eliminating dust mites that live in our homes, and since dust mites love a warm moist environment, towel heaters aid in maintaining a consistent room temperature and keep it moisture free. 

For homeowners or renovators, it’s worth taking a look at several kinds of radiant heaters for residences or businesses. Today we’ll discuss the electric cable heating system kind of radiant heaters.

Electric cable heating systems, often called line- or high-voltage systems, are gaining popularity and are ideal for heating smaller areas like bathrooms, kitchens, and sun rooms. These systems are comprised of a thermostat and a heating cable. On some radiant heater systems, the cable will be shipped to you as a large spool of cable. These systems are oftentimes less expensive, and give you the ability to space the cable how you want and customize a layout that will heat every square inch of your floor. Other systems have the cable attached to a plastic mesh or tape to create a mat to maintain its proper spacing.

Every available radiant heater cable system is equally effective, so when determining which system to purchase, you should look at the warranty of the product, along with the ease of installation. Some cables must be embedded in a separate layer of concrete or mortar, whereas other systems can simply be installed in the thinset.

Most cable systems can only be installed under tile; on others, if the cable is embedded in mortar or concrete, any flooring can be installed on top of the concrete.

Radiant Heaters Tip: When heating smaller areas with a radiant heater, it is nearly impossible to beat the simplicity and price of an electric cable heating system. 

Radiant Heaters Tip: When heating smaller areas, it is nearly impossible to beat the simplicity and price of an electric cable radiant heating system.