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The Myths of Low Voltage versus Line Voltage Radiant Systems

Low-voltage vs. Line-voltage

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. Warmzone offers both low-voltage and line-voltage systems. Both can provide excellent results for floor heating and snow melting applications.

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 to be embedded. 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.

Floor heating cable being installed

Some low voltage systems on the market have some distinct advantages over line voltage. RoofHeat STEP and FloorHeat STEP are low voltage, but does not rely on heat cables to generate heat. Instead it is constructed of a unique polymer heating element 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 RoofHeat STEP 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.

While Warmzone carries both low-voltage and line-voltage systems, low voltage systems are NOT necessarily more efficient. Since these systems have a much lower output of heat per square foot; they can take 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, most 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. The ideal low-voltage system features a flexible polymer heating element, such as RoofHeat STEP.

Low-voltage roof heating element
RoofHeat STEP low-voltage polymer heating element.

Warmzone also backs up its line voltage cable with one of the best manufacturer warranty in the business.

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.

NOTE: IN 2012, WARMZONE UPGRADED TO THE ADVANCED LOW-VOLTAGE SYSTEM, FEATURING A FLEXIBLE POLYMER HEATING ELEMENT, WHICH IS SAFER, EASIER TO INSTALL, AND MORE EFFICIENT THAN PREVIOUS LOW-VOLTAGE SYSTEMS.

Project Spotlight – Runaway Truck Ramp in Connecticut

Two of the biggest reasons for installing a snowmelt system are safety and maintenance free snow removal. Safety was also the biggest concern for a dangerous stretch of road in Connecticut that has already claimed four lives. In an effort to prevent more accidents, the Connecticut Department of Transportation (CDOT) set out to build a runaway truck ramp. CDOT chose Warmzone’s ClearZone snowmelt system to optimize the ramp’s safety.

Using saw-cut technology for installing radiant heat

The truck ramp is located in a mountainous metropolitan area of Connecticut, which created a unique problem. Because of limited space, the ramp could only be 480 feet long and required three metal nets to slow vehicle speed in the event of brake failure. The ramp walls are two feet thick and five feet high and reinforced from within with steel to stop a car from breaking through the ramp.

The nets coupled with the thick high walls made traditional methods of snow removal virtually impossible. There was no place to put plowed snow, and the metal safety nets had to be removed each time snow removal was required. The safety of the ramp was severely compromised when snow or ice gathered, making removal critical. A snow melting system was the best option to keep the ramp safe and functioning properly all year-round.

Grooves cut for heat cable  Retrofitting a runaway truck ramp with radiant heat

    Views of grooves cut for radiant heat cable to be installed.

Projects of this scale usually require more installation expertise than that of a small snowmelt system, which is why Warmzone’s technical specialist, Dan Mignogna, traveled to Connecticut to assist with the installation. With over 32 years of experience as an electrician and an expert in radiant heating, Mignogna worked closely with the CDOT team to determine the proper system installation and wiring of the automatic snow sensors.

The easiest method for installing a snowmelt system is beneath new asphalt, pavers or concrete. For this project, the ClearZone cables needed to be installed into existing asphalt using concrete saw-cutting technology. The cables were embedded 3 inches into the asphalt and covered using sealant. Each row of CZ cable was spaced 6 inches apart. The entire project required 12,960 feet of ClearZone snow melting cable.

The CDOT runaway truck ramp is scheduled for completion in early September of 2008. Click on the link for more information about ClearZone snowmelt systems.

Long Term Solutions for Dangerous Roof Snow and Ice

Many of us are diligent about keeping our walkways and driveways free from snow and ice, but we often overlook the hazards of snow and ice build-up on our roofs. If you live an area plagued with heavy snowfall, the accumulation of snow and ice on your roof can cause major structural damage, especially if you own an older home; not to mention the increased risk of serious injury resulting from falling ice. Finding an inexpensive long term solution, such as a radiant heating roof de-icing system, is essential to the structural integrity of your home as well as the safety of you and your guests.

According to the Institute for Business and Home Safety, most roofs are able to withstand around 20-pounds per square foot. This means your roof should not exceed 4 feet of new snow, 2 feet of old snow, or one inch of ice. To find out exactly how much weight your roof was designed to withstand, refer to your building design plan.

An even bigger danger is the formation of ice dams on roofs, usually caused by a warm attic melting snow, causing water to run down and refreeze near the roof gutter. Ice builds up and blocks regular drainage, allowing water to seep down and damage the attic and walls. The heavy ice formations on the eaves caused by ice dams are the most significant safety risks for businesses and home owners.

Manual roof snow and ice removal is dangerous business and can increase the chances of damage to the roof. Most safety and disaster prevention organizations recommend hiring a professional contractor to do the removal, but this only provides a one time, short term solution to the problem.

A roof de-icing system, such as Warmzone’s low-voltage roof heating systems, mount discreetly under the shingles (or metal) of the eaves and/or valleys of your roof, preventing the formation of ice dams. The option to heat the entire roof is also available. Warmzone also offers self-regulating radiant heat cable installed in channels of aluminum panels for maximum heat transfer to heat roof eaves. The system eliminates dangerous ice forming and greatly reduces the risk of damage to your roof. You will be able to skip the cost of hiring a professional contractor to remove snow after each heavy storm.

Self-regulating heat cable systems are surprisingly simple to install, offer maintenance free snow and ice removal, and best of all, they are efficient and have low operating costs. Investing in a roof de-icing system also raises the value of your home and extend the life of your roof.

Other preventive measures should be taken before snow begins to fall, such as clearing debris from all drainage systems. During winter months, it is important to keep your window wells and walls free of snow. Simple maintenance and the installation of a roof de-icing system will go a long way towards protecting your home or business from natural disasters, and eliminate the possibility of injury caused by falling ice.


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 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.

Automated Radiant Heat Snow Removal; What More Could Grandma Want?

Several of the people in my area are over the age of 75 and live alone. Being in an area that receives heavy snow fall, I can’t help but wonder how they can manage snow removal. More often than not, the elderly are at the mercy of their family or neighbors’ hospitality. Many elderly feel as though they are burdens to others, and some even hire professionals to remove snow. Senior citizens especially would benefit immensely from an automatic heated driveway or walkway snow melting system.

Considering that 50 percent of people over the age of 75 will either die or be forced to enter institutional care because of injuries sustained from falls, any kinds of safety precautions are extremely important. Walkways that are frequently used, such as entryways and paths to trash cans, are the highest priority for snow melting. An electric snowmelt system would automatically remove snow and ice and ensure safety, as well as help the elderly to avoid the feeling of burdening friends and family.

The cost of healthcare continues to rise at unprecedented rates, bringing “prevention” to the forefront of personal care. Most businesses are installing heated walkways in areas where safety is the highest priority, such as disability ramps and steep walkways that receive heavy traffic. The cost of installing and running a snow melting system is much lower than the cost of medical bills or lawsuits resulting from someone slipping on a business premises.

Heated driveways and electric snow melting systems are environmentally friendly, unlike using salt and chemicals, which causes calcium chloride to damage nearby foliage and run into rivers and water supplies. The cost to operate a snow melting system is much less than the cost to use salt and chemicals after each snowfall or hire maintenance crews to remove snow.

Several snowmelt options are available. Radiant snowmelt systems can be installed to heat entire driveways and sidewalks, or radiant heating cable can be installed in specific areas such as a pair of 2-foot wide tire tracks on a driveway or heating the middle 3 feet of a sidewalk for more economical reasons. The heated driveway systems available on www.heatdrive.com offer automated operation which includes a sophisticated activation device that turns on the snow melting system when it senses precipitation and temperatures are below 39 degrees Fahrenheit. Snow sensors like these are necessary for the most energy-efficient snowmelt systems and prevent needless energy consumption.

Electric snow melting systems have come a long way since they were first introduced. A heated driveway was originally considered a luxury that only the rich could afford, but current radiant heat systems cost less per square foot, are easily installed and consume less energy. Snowmelt systems are available in electric or hydronic, but typically the electric systems are easier to install and require less maintenance. For more information on electric radiant heat and FREE estimate and options for your roof heating and ice melting project.

Warmzone Offers Powerblanket Concrete Curing Blankets

Cold weather is a common roadblock to pouring concrete  and completing construction projects. Despite the arrival of spring, the ground can remain frozen for a considerable time, further delaying projects and adding to construction costs. A heated, insulated concrete curing blanket from Warmzone is a simple, energy-efficient solution for pouring concrete and completing quality cement work in cold conditions.

Pouring concrete in cold weather is usually not a good idea. Even with the arrival of warmer temperatures, the ground can still remain frozen in many parts of the country. Typically, this means that construction projects involving concrete must wait until the ground thaws.

With the close of winter, most do-it-yourself types are eager to tackle projects that have been “on hold” during the cold season. However, in early spring, temperatures can still dip below 40 degrees Fahrenheit, and at that temperature freshly-poured concrete can freeze or not cure properly.

The Powerblanket® is an ideal solution to pouring concrete in cold weather. Electrically-heated Powerblankets are extremely durable, weatherproof concrete curing blankets for home and construction projects. From large outdoor projects to small indoor needs, versatile Powerblankets are available in a variety of sizes and designed to link together to fit the specific space requirements of your projects.

Powerblanket concrete curing mats and barrel warmers

Most people try to use blankets or straw to keep concrete from freezing in cold weather. However just keeping the concrete from freezing isn’t enough. “No amount of blankets or straw will thaw frozen ground — and the last thing you want to do is pour concrete on frozen ground,” noted Warmzone National Sales Manager, Bryan Morris.

While it may be possible able to trap in some heat, this insulation won’t keep the temperature at an ideal level for maximum curing efficiency. “To pour concrete you need to have the temperature between 65 – 85° Fahrenheit – both to lay a strong foundation and to save hours and hours of time. Powerblanket is a solution,” Morris added. The durable blankets are also energy efficient.

The colder the temperature that concrete gets exposed to, the longer it will take to set and reach its maximum strength. For example, concrete that is steady at 70°F will set in approximately six hours, but at 40°F it will take 14 hours. At 70°F your concrete will be almost three times as strong as it would be if temperatures maintained at 40°F.

Powerblankets can be used for other insulation and warming needs in cold water, including: engine warming, bucket heating, wall curing, ground thawing, equipment warming, frozen pipe thawing, curb and gutter thawing, etc. The curing blankets can also be used on cement walls and columns.

The rugged Powerblanket is safe to handle in inclement weather and is extremely durable. The insulated, vinyl covered blankets can be driven on, pulled over re-bar, dragged through mud and water, buried, and then rolled up or folded until it is needed again. Powerblankets can be a tremendous asset to contractors and do-it-yourselfers by preventing construction delays as well as enhancing the quality of cement work. The applications of the Powerblanket are virtually limitless.


About Warmzone
Warmzone’s mission is to match customer’s needs with the finest radiant heating systems available. As an intermediary between project requirements and a variety of system choices, Warmzone and warmzone.com offer non-biased, individualized solutions that factor the installation, durability, performance and operational investment as the key criteria of their customers.

Electric Radiant Heat

Electric radiant heating systems are very cost-effective solutions for smaller spaces (1-5 rooms) because they are easy to install and have a very low start-up cost. An electric thermostat is all that is required and costs only about $100-$200. Another advantage of electric radiant floor heating over a warm-water system is the floor build up or height. Floor build up can be from as little as 2mm. The electric cables are usually installed onto an insulation board or directly onto the subfloor or padding (under carpet or laminate), then the floor covering is placed directly over the heating system or thinset.

Electric radiant floor heating also benefits from faster installation times, with a typical installation only taking half day to a day depending on size to install. Also warm up times are generally a lot quicker than “wet” systems because the cables are installed directly below the finished flooring making it a direct acting heat source rather than a storage heater.

Electric radiant heat used to be supplied as one long continuous length of cable with the consumer having to weave the cable up and down the floor at a pre-determined spacing and making a return loop to complete the circuit. The main problem with this was the installation time taking quite a while, and also the risk of hot and cold spots due to uneven cable spacing, cables spaced close together give off more heat, and visa versa.

Recent designs in electric radiant heat cables have a built in return meaning that you only have one end to connect instead of having to close the circuit by bringing each end of the cable back to the thermostat. These are excellent electric radiant heat cables and make the installation much quicker. With the introduction of the built in return came the “cable mat” these have revolutionized the electric radiant heat cables due to the simplicity of the installation.

Electric radiant heat cable mats have taken the hard work out of the install by having the radiant heating cable already pre-spaced on to a nylon mesh and all you have to do is simply start at your thermostat location and roll it out over the floor until it’s all used up. These save time and offer less risk of having hot and cold spots.


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.

Which Radiant Floor Heating System is Best for Me

If you are looking to warm your floors with a radiant heat system, and have typed “radiant heat system” into a search engine, you might find yourself scratching your head at this point. There are dozens of products available to purchase, and there are even more companies telling you that their product is the best.

So which product is the best? Should you install a hydronic heating system that pumps specially treated hot water through PEX tubing under your floors, an electric cable heating system, or a low-voltage system with flexible polymer heating panels? The answer lies in the type of project you are doing. No single system is ideal for every project, but there is an ideal system for every project.

Hydronic Heating Systems
Hydronic floor heating is the oldest and most popular type of radiant floor heating. These systems are comprised of a boiler or hot water heater, pumps, manifolds, PEX tubing, thermostat, and advanced Rau Panels. Hydronic heating is the most complex of all radiant heat systems. These systems require trained professionals to design and perform the installation. Your best economies of scale are achieved for hydronic systems in large areas or entire homes because of their expensive components and installation costs. However, because hydronic systems can operate on natural gas, oil or propane etc., the operational costs can be a little lower than that of electric floor heating systems.

Hydronic floor heating system featuring RAU Panels

Hydronic systems can be installed under any type of flooring. Most hydronic systems require hot water tubing to be installed in a 2-4 inch bed of light concrete or specially made panels, and are best installed during the initial construction because of its weight load demands and adjustments to floor height. Recent low-mass products have been developed to avoid these challenges by fitting the tubing into pre-cut Rau Panels, making hydronic systems more convenient and possible for most major remodeling projects.

If you want to heat smaller areas like a bathroom or kitchen, a hydronic floor heating system may not be the best value for your project. The complexity and cost of installing the system, along with the long-term maintenance and up-keep required, is not worth the small amount you will save in operational costs. Electric floor heating systems are highly preferred over hydronic systems for small floor heating applications.

Electric Cable Heating
Electric cable heating systems, often called line- or high-voltage systems, are gaining popularity and are ideal for heating smaller areas (10-300 square feet) like bathrooms, kitchens, and sun rooms. These systems are comprised of a thermostat and a heating cable.  The most popular heat cable is Warmzone’s ComfortTile cable.

ComfortTile floor heating systems feature heat cable that is available on spools as well as cable that is pre-spaced on a flexible mesh with adhesive backing for easy “roll out” installation. The cable on the spool is oftentimes less expensive, and gives you the ability to space the cable how you want and customize a layout that will heat every square inch of your floor. The cable in mats allows for quick and easy installation.

Every available 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. However, on others, if the cable is embedded in mortar or concrete, any flooring can be installed on top of the concrete. When heating smaller areas, it is nearly impossible to beat the simplicity and price of an electric cable heating system.

Low-Voltage Heating Element
Finally, there are low-voltage radiant heat systems. These systems are ideal for mid-size to larger areas (300-3000 square feet) and are comprised of a control box, transformer, heating screen or cable, and thermostat. A unique advantage to a FloorHeat low-voltage system is the extremely low profile of the heating element. FloorHeat STEP is extremely thin and does not buildup floors during the installation. The floor heating system features a 12-inch wide, durable polymer heating element that is also self-regulating.

Illustration of FloorHeat installed under hardwood floor

It can be installed directly under any type of flooring including hardwood, tile, laminates, and carpet. Whereas most cable systems must be installed on top of the concrete board when installing tile, FloorHeat can be installed underneath it. These systems are easy to install and don’t require maintenance like a hydronic system. The self-regulating capability of FloorHeat means that when the ambient temperature rises, the electrical resistance increases and the consumption of electricity decreases. For this reason, the element cannot overheat, and the system is extremely energy efficient.

Radiant heat technology has made significant advances over the years and is an excellent way to supplement your existing heating system or be your sole source of heat. One good way to be assured that you’re being sold the best system for your project is to buy from a company that offers all of the available types of radiant heat.

Warmzone is one company that carries a wide variety of radiant systems and is dedicated to specifying the product that makes the most sense for each individual job. Without a bias towards one system, and unmatched customer services (including installation support and free installation training), Warmzone has become a consumer advocate in the radiant industry that can save you time and money.

Warmzone has already done the research and is committed to working with only the best products on the market. Because Warmzone is a leading nationwide wholesaler, you can receive the best pricing by purchasing direct. Receive a free estimate for your project by submitting a quote request or calling Warmzone at 1-888-488-WARM (9276).